Network entity ids (#4252)

Robust.Client/Console/Commands/AddCompCommand.cs

@@ -22,7 +22,8 @@ namespace Robust.Client.Console.Commands
                 return;
             }
 
-            var entity = EntityUid.Parse(args[0]);
+            var netEntity = NetEntity.Parse(args[0]);
+            var entity = _entityManager.GetEntity(netEntity);
             var componentName = args[1];
 
             var component = (Component) _componentFactory.GetComponent(componentName);
@@ -49,7 +50,8 @@ namespace Robust.Client.Console.Commands
                 return;
             }
 
-            var entityUid = EntityUid.Parse(args[0]);
+            var netEntity = NetEntity.Parse(args[0]);
+            var entityUid = _entityManager.GetEntity(netEntity);
             var componentName = args[1];
 
             var registration = _componentFactory.GetRegistration(componentName);

Robust.Client/Console/Commands/Debug.cs

@@ -296,6 +296,7 @@ namespace Robust.Client.Console.Commands
 
     internal sealed class SnapGridGetCell : LocalizedCommands
     {
+        [Dependency] private readonly IEntityManager _entManager = default!;
         [Dependency] private readonly IMapManager _map = default!;
 
         public override string Command => "sggcell";
@@ -310,7 +311,7 @@ namespace Robust.Client.Console.Commands
 
             string indices = args[1];
 
-            if (!EntityUid.TryParse(args[0], out var gridUid))
+            if (!NetEntity.TryParse(args[0], out var gridNet))
             {
                 shell.WriteError($"{args[0]} is not a valid entity UID.");
                 return;
@@ -322,7 +323,7 @@ namespace Robust.Client.Console.Commands
                 return;
             }
 
-            if (_map.TryGetGrid(gridUid, out var grid))
+            if (_map.TryGetGrid(_entManager.GetEntity(gridNet), out var grid))
             {
                 foreach (var entity in grid.GetAnchoredEntities(new Vector2i(
                              int.Parse(indices.Split(',')[0], CultureInfo.InvariantCulture),
@@ -430,6 +431,7 @@ namespace Robust.Client.Console.Commands
 
     internal sealed class GridTileCount : LocalizedCommands
     {
+        [Dependency] private readonly IEntityManager _entManager = default!;
         [Dependency] private readonly IMapManager _map = default!;
 
         public override string Command => "gridtc";
@@ -442,7 +444,8 @@ namespace Robust.Client.Console.Commands
                 return;
             }
 
-            if (!EntityUid.TryParse(args[0], out var gridUid))
+            if (!NetEntity.TryParse(args[0], out var gridUidNet) ||
+                !_entManager.TryGetEntity(gridUidNet, out var gridUid))
             {
                 shell.WriteLine($"{args[0]} is not a valid entity UID.");
                 return;

Robust.Client/GameObjects/ClientEntityManager.Network.cs

@@ -0,0 +1,53 @@
+using System;
+using System.Collections.Generic;
+using Robust.Shared.GameObjects;
+using Robust.Shared.Map;
+using Robust.Shared.Utility;
+
+namespace Robust.Client.GameObjects;
+
+public sealed partial class ClientEntityManager
+{
+    protected override NetEntity GenerateNetEntity() => new(NextNetworkId++ | NetEntity.ClientEntity);
+
+    /// <summary>
+    /// If the client fails to resolve a NetEntity then during component state handling or the likes we
+    /// flag that comp state as requiring re-running if that NetEntity comes in.
+    /// </summary>
+    /// <returns></returns>
+    internal readonly Dictionary<NetEntity, List<(Type type, EntityUid Owner)>> PendingNetEntityStates = new();
+
+    public override bool IsClientSide(EntityUid uid, MetaDataComponent? metadata = null)
+    {
+        // Can't log false because some content code relies on invalid UIDs.
+        if (!MetaQuery.Resolve(uid, ref metadata, false))
+            return false;
+
+        return metadata.NetEntity.IsClientSide();
+    }
+
+    public override EntityUid EnsureEntity<T>(NetEntity nEntity, EntityUid callerEntity)
+    {
+        if (!nEntity.Valid)
+        {
+            return EntityUid.Invalid;
+        }
+
+        if (NetEntityLookup.TryGetValue(nEntity, out var entity))
+        {
+            return entity;
+        }
+
+        // Flag the callerEntity to have their state potentially re-run later.
+        var pending = PendingNetEntityStates.GetOrNew(nEntity);
+        pending.Add((typeof(T), callerEntity));
+
+        return entity;
+    }
+
+    public override EntityCoordinates EnsureCoordinates<T>(NetCoordinates netCoordinates, EntityUid callerEntity)
+    {
+        var entity = EnsureEntity<T>(netCoordinates.NetEntity, callerEntity);
+        return new EntityCoordinates(entity, netCoordinates.Position);
+    }
+}

Robust.Client/GameObjects/ClientEntityManager.cs

@@ -16,7 +16,7 @@ namespace Robust.Client.GameObjects
     /// <summary>
     /// Manager for entities -- controls things like template loading and instantiation
     /// </summary>
-    public sealed class ClientEntityManager : EntityManager, IClientEntityManagerInternal
+    public sealed partial class ClientEntityManager : EntityManager, IClientEntityManagerInternal
     {
         [Dependency] private readonly IPlayerManager _playerManager = default!;
         [Dependency] private readonly IClientNetManager _networkManager = default!;
@@ -25,8 +25,6 @@ namespace Robust.Client.GameObjects
         [Dependency] private readonly IBaseClient _client = default!;
         [Dependency] private readonly IReplayRecordingManager _replayRecording = default!;
 
-        protected override int NextEntityUid { get; set; } = EntityUid.ClientUid + 1;
-
         public override void Initialize()
         {
             SetupNetworking();
@@ -37,13 +35,16 @@ namespace Robust.Client.GameObjects
 
         public override void FlushEntities()
         {
+            // Server doesn't network deletions on client shutdown so we need to
+            // manually clear these out or risk stale data getting used.
+            PendingNetEntityStates.Clear();
             using var _ = _gameTiming.StartStateApplicationArea();
             base.FlushEntities();
         }
 
-        EntityUid IClientEntityManagerInternal.CreateEntity(string? prototypeName, EntityUid uid)
+        EntityUid IClientEntityManagerInternal.CreateEntity(string? prototypeName)
         {
-            return base.CreateEntity(prototypeName, uid);
+            return base.CreateEntity(prototypeName);
         }
 
         void IClientEntityManagerInternal.InitializeEntity(EntityUid entity, MetaDataComponent? meta)
@@ -66,7 +67,7 @@ namespace Robust.Client.GameObjects
 
         public override void QueueDeleteEntity(EntityUid uid)
         {
-            if (uid.IsClientSide())
+            if (IsClientSide(uid))
             {
                 base.QueueDeleteEntity(uid);
                 return;

Robust.Client/GameObjects/EntitySystems/AnimationPlayerSystem.cs

@@ -128,7 +128,7 @@ namespace Robust.Client.GameObjects
                     return;
                 }
 
-                if (component.Owner.IsClientSide() || !animatedComp.NetSyncEnabled)
+                if (IsClientSide(component.Owner) || !animatedComp.NetSyncEnabled)
                     continue;
 
                 var reg = _compFact.GetRegistration(animatedComp);

Robust.Client/GameObjects/EntitySystems/AudioSystem.cs

@@ -81,9 +81,13 @@ public sealed class AudioSystem : SharedAudioSystem
     #region Event Handlers
     private void PlayAudioEntityHandler(PlayAudioEntityMessage ev)
     {
-        var stream = EntityManager.EntityExists(ev.EntityUid)
-            ? (PlayingStream?) Play(ev.FileName, ev.EntityUid, ev.FallbackCoordinates, ev.AudioParams, false)
-            : (PlayingStream?) Play(ev.FileName, ev.Coordinates, ev.FallbackCoordinates, ev.AudioParams, false);
+        var uid = GetEntity(ev.NetEntity);
+        var coords = GetCoordinates(ev.Coordinates);
+        var fallback = GetCoordinates(ev.FallbackCoordinates);
+
+        var stream = EntityManager.EntityExists(uid)
+            ? (PlayingStream?) Play(ev.FileName, uid, fallback, ev.AudioParams, false)
+            : (PlayingStream?) Play(ev.FileName, coords, fallback, ev.AudioParams, false);
 
         if (stream != null)
             stream.NetIdentifier = ev.Identifier;
@@ -98,7 +102,10 @@ public sealed class AudioSystem : SharedAudioSystem
 
     private void PlayAudioPositionalHandler(PlayAudioPositionalMessage ev)
     {
-        var stream = (PlayingStream?) Play(ev.FileName, ev.Coordinates, ev.FallbackCoordinates, ev.AudioParams, false);
+        var coords = GetCoordinates(ev.Coordinates);
+        var fallback = GetCoordinates(ev.FallbackCoordinates);
+
+        var stream = (PlayingStream?) Play(ev.FileName, coords, fallback, ev.AudioParams, false);
         if (stream != null)
             stream.NetIdentifier = ev.Identifier;
     }
@@ -383,8 +390,8 @@ public sealed class AudioSystem : SharedAudioSystem
             _replayRecording.RecordReplayMessage(new PlayAudioEntityMessage
             {
                 FileName = filename,
-                EntityUid = entity,
-                FallbackCoordinates = fallbackCoordinates ?? default,
+                NetEntity = GetNetEntity(entity),
+                FallbackCoordinates = GetNetCoordinates(fallbackCoordinates) ?? default,
                 AudioParams = audioParams ?? AudioParams.Default
             });
         }
@@ -437,8 +444,8 @@ public sealed class AudioSystem : SharedAudioSystem
             _replayRecording.RecordReplayMessage(new PlayAudioPositionalMessage
             {
                 FileName = filename,
-                Coordinates = coordinates,
-                FallbackCoordinates = fallbackCoordinates,
+                Coordinates = GetNetCoordinates(coordinates),
+                FallbackCoordinates = GetNetCoordinates(fallbackCoordinates),
                 AudioParams = audioParams ?? AudioParams.Default
             });
         }

Robust.Client/GameObjects/EntitySystems/ContainerSystem.cs

@@ -1,3 +1,4 @@
+using System;
 using Robust.Shared.Collections;
 using Robust.Shared.Containers;
 using Robust.Shared.GameObjects;
@@ -5,13 +6,11 @@ using Robust.Shared.GameStates;
 using Robust.Shared.IoC;
 using Robust.Shared.Map;
 using Robust.Shared.Network;
-using Robust.Shared.Serialization;
 using Robust.Shared.Utility;
-using System;
 using System.Collections.Generic;
 using System.Diagnostics.CodeAnalysis;
 using System.Linq;
-using Robust.Shared.Physics.Components;
+using Robust.Shared.Serialization;
 using static Robust.Shared.Containers.ContainerManagerComponent;
 
 namespace Robust.Client.GameObjects
@@ -23,14 +22,20 @@ namespace Robust.Client.GameObjects
         [Dependency] private readonly IDynamicTypeFactoryInternal _dynFactory = default!;
         [Dependency] private readonly PointLightSystem _lightSys = default!;
 
+        private EntityQuery<PointLightComponent> _pointLightQuery;
+        private EntityQuery<SpriteComponent> _spriteQuery;
+
         private readonly HashSet<EntityUid> _updateQueue = new();
 
-        public readonly Dictionary<EntityUid, IContainer> ExpectedEntities = new();
+        public readonly Dictionary<NetEntity, BaseContainer> ExpectedEntities = new();
 
         public override void Initialize()
         {
             base.Initialize();
 
+            _pointLightQuery = GetEntityQuery<PointLightComponent>();
+            _spriteQuery = GetEntityQuery<SpriteComponent>();
+
             EntityManager.EntityInitialized += HandleEntityInitialized;
             SubscribeLocalEvent<ContainerManagerComponent, ComponentHandleState>(HandleComponentState);
 
@@ -43,20 +48,18 @@ namespace Robust.Client.GameObjects
             base.Shutdown();
         }
 
-        protected override void ValidateMissingEntity(EntityUid uid, IContainer cont, EntityUid missing)
+        protected override void ValidateMissingEntity(EntityUid uid, BaseContainer cont, EntityUid missing)
         {
-            DebugTools.Assert(ExpectedEntities.TryGetValue(missing, out var expectedContainer) && expectedContainer == cont && cont.ExpectedEntities.Contains(missing));
+            var netEntity = GetNetEntity(missing);
+            DebugTools.Assert(ExpectedEntities.TryGetValue(netEntity, out var expectedContainer) && expectedContainer == cont && cont.ExpectedEntities.Contains(netEntity));
         }
 
         private void HandleEntityInitialized(EntityUid uid)
         {
-            if (!RemoveExpectedEntity(uid, out var container))
+            if (!RemoveExpectedEntity(GetNetEntity(uid), out var container))
                 return;
 
-            if (container.Deleted)
-                return;
-
-            container.Insert(uid);
+            container.Insert(uid, EntityManager, transform: TransformQuery.GetComponent(uid), meta: MetaQuery.GetComponent(uid));
         }
 
         private void HandleComponentState(EntityUid uid, ContainerManagerComponent component, ref ComponentHandleState args)
@@ -64,23 +67,24 @@ namespace Robust.Client.GameObjects
             if (args.Current is not ContainerManagerComponentState cast)
                 return;
 
-            var metaQuery = GetEntityQuery<MetaDataComponent>();
-            var xformQuery = GetEntityQuery<TransformComponent>();
-            var xform = xformQuery.GetComponent(uid);
+            var xform = TransformQuery.GetComponent(uid);
 
             // Delete now-gone containers.
             var toDelete = new ValueList<string>();
             foreach (var (id, container) in component.Containers)
             {
                 if (cast.Containers.ContainsKey(id))
+                {
+                    DebugTools.Assert(cast.Containers[id].ContainerType == container.GetType().Name);
                     continue;
+                }
 
                 foreach (var entity in container.ContainedEntities.ToArray())
                 {
                     container.Remove(entity,
                         EntityManager,
-                        xformQuery.GetComponent(entity),
-                        metaQuery.GetComponent(entity),
+                        TransformQuery.GetComponent(entity),
+                        MetaQuery.GetComponent(entity),
                         force: true,
                         reparent: false);
 
@@ -98,26 +102,32 @@ namespace Robust.Client.GameObjects
 
             // Add new containers and update existing contents.
 
-            foreach (var (containerType, id, showEnts, occludesLight, entityUids) in cast.Containers.Values)
+            foreach (var (id, data) in cast.Containers)
             {
                 if (!component.Containers.TryGetValue(id, out var container))
                 {
-                    container = ContainerFactory(component, containerType, id);
+                    var type = _serializer.FindSerializedType(typeof(BaseContainer), data.ContainerType);
+                    container = _dynFactory.CreateInstanceUnchecked<BaseContainer>(type!, inject:false);
+                    container.Init(id, uid, component);
                     component.Containers.Add(id, container);
                 }
 
-                // sync show flag
-                container.ShowContents = showEnts;
-                container.OccludesLight = occludesLight;
+                DebugTools.Assert(container.ID == id);
+                container.ShowContents = data.ShowContents;
+                container.OccludesLight = data.OccludesLight;
 
                 // Remove gone entities.
                 var toRemove = new ValueList<EntityUid>();
+
+                DebugTools.Assert(!container.Contains(EntityUid.Invalid));
+
+                var stateNetEnts = data.ContainedEntities;
+                var stateEnts = GetEntityArray(stateNetEnts); // No need to ensure entities.
+
                 foreach (var entity in container.ContainedEntities)
                 {
-                    if (!entityUids.Contains(entity))
-                    {
+                    if (!stateEnts.Contains(entity))
                         toRemove.Add(entity);
-                    }
                 }
 
                 foreach (var entity in toRemove)
@@ -125,8 +135,8 @@ namespace Robust.Client.GameObjects
                     container.Remove(
                         entity,
                         EntityManager,
-                        xformQuery.GetComponent(entity),
-                        metaQuery.GetComponent(entity),
+                        TransformQuery.GetComponent(entity),
+                        MetaQuery.GetComponent(entity),
                         force: true,
                         reparent: false);
 
@@ -134,13 +144,11 @@ namespace Robust.Client.GameObjects
                 }
 
                 // Remove entities that were expected, but have been removed from the container.
-                var removedExpected = new ValueList<EntityUid>();
-                foreach (var entityUid in container.ExpectedEntities)
+                var removedExpected = new ValueList<NetEntity>();
+                foreach (var netEntity in container.ExpectedEntities)
                 {
-                    if (!entityUids.Contains(entityUid))
-                    {
-                        removedExpected.Add(entityUid);
-                    }
+                    if (!stateNetEnts.Contains(netEntity))
+                        removedExpected.Add(netEntity);
                 }
 
                 foreach (var entityUid in removedExpected)
@@ -149,14 +157,20 @@ namespace Robust.Client.GameObjects
                 }
 
                 // Add new entities.
-                foreach (var entity in entityUids)
+                for (var i = 0; i < stateNetEnts.Length; i++)
                 {
-                    if (!EntityManager.TryGetComponent(entity, out MetaDataComponent? meta))
+                    var entity = stateEnts[i];
+                    var netEnt = stateNetEnts[i];
+                    if (!entity.IsValid())
                     {
-                        AddExpectedEntity(entity, container);
+                        DebugTools.Assert(netEnt.IsValid());
+                        AddExpectedEntity(netEnt, container);
                         continue;
                     }
 
+                    var meta = MetaData(entity);
+                    DebugTools.Assert(meta.NetEntity == netEnt);
+
                     // If an entity is currently in the shadow realm, it means we probably left PVS and are now getting
                     // back into range. We do not want to directly insert this entity, as IF the container and entity
                     // transform states did not get sent simultaneously, the entity's transform will be modified by the
@@ -166,18 +180,18 @@ namespace Robust.Client.GameObjects
                     // containers/players.
                     if ((meta.Flags & MetaDataFlags.Detached) != 0)
                     {
-                        AddExpectedEntity(entity, container);
+                        AddExpectedEntity(netEnt, container);
                         continue;
                     }
 
                     if (container.Contains(entity))
                         continue;
 
-                    RemoveExpectedEntity(entity, out _);
+                    RemoveExpectedEntity(netEnt, out _);
                     container.Insert(entity, EntityManager,
-                        xformQuery.GetComponent(entity),
+                        TransformQuery.GetComponent(entity),
                         xform,
-                        metaQuery.GetComponent(entity),
+                        MetaQuery.GetComponent(entity),
                         force: true);
 
                     DebugTools.Assert(container.Contains(entity));
@@ -198,7 +212,7 @@ namespace Robust.Client.GameObjects
             if (message.OldParent != null && message.OldParent.Value.IsValid())
                 return;
 
-            if (!RemoveExpectedEntity(message.Entity, out var container))
+            if (!RemoveExpectedEntity(GetNetEntity(message.Entity), out var container))
                 return;
 
             if (xform.ParentUid != container.Owner)
@@ -208,84 +222,69 @@ namespace Robust.Client.GameObjects
                 return;
             }
 
-            if (container.Deleted)
-                return;
-
             container.Insert(message.Entity, EntityManager);
         }
 
-        private IContainer ContainerFactory(ContainerManagerComponent component, string containerType, string id)
+        public void AddExpectedEntity(NetEntity netEntity, BaseContainer container)
         {
-            var type = _serializer.FindSerializedType(typeof(IContainer), containerType);
-            if (type is null) throw new ArgumentException($"Container of type {containerType} for id {id} cannot be found.");
+#if DEBUG
+            var uid = GetEntity(netEntity);
 
-            var newContainer = _dynFactory.CreateInstanceUnchecked<BaseContainer>(type);
-            newContainer.ID = id;
-            newContainer.Manager = component;
-            return newContainer;
-        }
+            if (TryComp<MetaDataComponent>(uid, out var meta))
+            {
+                DebugTools.Assert((meta.Flags & ( MetaDataFlags.Detached | MetaDataFlags.InContainer) ) == MetaDataFlags.Detached,
+                    $"Adding entity {ToPrettyString(uid)} to list of expected entities for container {container.ID} in {ToPrettyString(container.Owner)}, despite it already being in a container.");
+            }
+#endif
 
-        public void AddExpectedEntity(EntityUid uid, IContainer container)
-        {
-            DebugTools.Assert(!TryComp(uid, out MetaDataComponent? meta) ||
-                (meta.Flags & ( MetaDataFlags.Detached | MetaDataFlags.InContainer) ) == MetaDataFlags.Detached,
-                $"Adding entity {ToPrettyString(uid)} to list of expected entities for container {container.ID} in {ToPrettyString(container.Owner)}, despite it already being in a container.");
-
-            if (!ExpectedEntities.TryAdd(uid, container))
+            if (!ExpectedEntities.TryAdd(netEntity, container))
             {
                 // It is possible that we were expecting this entity in one container, but it has now moved to another
                 // container, and this entity's state is just being applied before the old container is getting updated.
-                var oldContainer = ExpectedEntities[uid];
-                ExpectedEntities[uid] = container;
-                DebugTools.Assert(oldContainer.ExpectedEntities.Contains(uid),
-                    $"Entity {ToPrettyString(uid)} is expected, but not expected in the given container? Container: {oldContainer.ID} in {ToPrettyString(oldContainer.Owner)}");
-                oldContainer.ExpectedEntities.Remove(uid);
+                var oldContainer = ExpectedEntities[netEntity];
+                ExpectedEntities[netEntity] = container;
+                DebugTools.Assert(oldContainer.ExpectedEntities.Contains(netEntity),
+                    $"Entity {netEntity} is expected, but not expected in the given container? Container: {oldContainer.ID} in {ToPrettyString(oldContainer.Owner)}");
+                oldContainer.ExpectedEntities.Remove(netEntity);
             }
 
-            DebugTools.Assert(!container.ExpectedEntities.Contains(uid),
-                $"Contained entity {ToPrettyString(uid)} was not yet expected by the system, but was already expected by the container: {container.ID} in {ToPrettyString(container.Owner)}");
-            container.ExpectedEntities.Add(uid);
+            DebugTools.Assert(!container.ExpectedEntities.Contains(netEntity),
+                $"Contained entity {netEntity} was not yet expected by the system, but was already expected by the container: {container.ID} in {ToPrettyString(container.Owner)}");
+            container.ExpectedEntities.Add(netEntity);
         }
 
-        public bool RemoveExpectedEntity(EntityUid uid, [NotNullWhen(true)] out IContainer? container)
+        public bool RemoveExpectedEntity(NetEntity netEntity, [NotNullWhen(true)] out BaseContainer? container)
         {
-            if (!ExpectedEntities.Remove(uid, out container))
+            if (!ExpectedEntities.Remove(netEntity, out container))
                 return false;
 
-            DebugTools.Assert(container.ExpectedEntities.Contains(uid),
-                $"While removing expected contained entity {ToPrettyString(uid)}, the entity was missing from the container expected set. Container: {container.ID} in {ToPrettyString(container.Owner)}");
-            container.ExpectedEntities.Remove(uid);
+            DebugTools.Assert(container.ExpectedEntities.Contains(netEntity),
+                $"While removing expected contained entity {ToPrettyString(netEntity)}, the entity was missing from the container expected set. Container: {container.ID} in {ToPrettyString(container.Owner)}");
+            container.ExpectedEntities.Remove(netEntity);
             return true;
         }
 
         public override void FrameUpdate(float frameTime)
         {
             base.FrameUpdate(frameTime);
-            var pointQuery = EntityManager.GetEntityQuery<PointLightComponent>();
-            var spriteQuery = EntityManager.GetEntityQuery<SpriteComponent>();
-            var xformQuery = EntityManager.GetEntityQuery<TransformComponent>();
 
             foreach (var toUpdate in _updateQueue)
             {
                 if (Deleted(toUpdate))
                     continue;
 
-                UpdateEntityRecursively(toUpdate, xformQuery, pointQuery, spriteQuery);
+                UpdateEntityRecursively(toUpdate);
             }
 
             _updateQueue.Clear();
         }
 
-        private void UpdateEntityRecursively(
-            EntityUid entity,
-            EntityQuery<TransformComponent> xformQuery,
-            EntityQuery<PointLightComponent> pointQuery,
-            EntityQuery<SpriteComponent> spriteQuery)
+        private void UpdateEntityRecursively(EntityUid entity)
         {
             // Recursively go up parents and containers to see whether both sprites and lights need to be occluded
             // Could maybe optimise this more by checking nearest parent that has sprite / light and whether it's container
             // occluded but this probably isn't a big perf issue.
-            var xform = xformQuery.GetComponent(entity);
+            var xform = TransformQuery.GetComponent(entity);
             var parent = xform.ParentUid;
             var child = entity;
             var spriteOccluded = false;
@@ -293,7 +292,7 @@ namespace Robust.Client.GameObjects
 
             while (parent.IsValid() && (!spriteOccluded || !lightOccluded))
             {
-                var parentXform = xformQuery.GetComponent(parent);
+                var parentXform = TransformQuery.GetComponent(parent);
                 if (TryComp<ContainerManagerComponent>(parent, out var manager) && manager.TryGetContainer(child, out var container))
                 {
                     spriteOccluded = spriteOccluded || !container.ShowContents;
@@ -308,24 +307,21 @@ namespace Robust.Client.GameObjects
             // This is the CBT bit.
             // The issue is we need to go through the children and re-check whether they are or are not contained.
             // if they are contained then the occlusion values may need updating for all those children
-            UpdateEntity(entity, xform, xformQuery, pointQuery, spriteQuery, spriteOccluded, lightOccluded);
+            UpdateEntity(entity, xform, spriteOccluded, lightOccluded);
         }
 
         private void UpdateEntity(
             EntityUid entity,
             TransformComponent xform,
-            EntityQuery<TransformComponent> xformQuery,
-            EntityQuery<PointLightComponent> pointQuery,
-            EntityQuery<SpriteComponent> spriteQuery,
             bool spriteOccluded,
             bool lightOccluded)
         {
-            if (spriteQuery.TryGetComponent(entity, out var sprite))
+            if (_spriteQuery.TryGetComponent(entity, out var sprite))
             {
                 sprite.ContainerOccluded = spriteOccluded;
             }
 
-            if (pointQuery.TryGetComponent(entity, out var light))
+            if (_pointLightQuery.TryGetComponent(entity, out var light))
                 _lightSys.SetContainerOccluded(entity, lightOccluded, light);
 
             var childEnumerator = xform.ChildEnumerator;
@@ -346,14 +342,14 @@ namespace Robust.Client.GameObjects
                         childLightOccluded = childLightOccluded || container.OccludesLight;
                     }
 
-                    UpdateEntity(child.Value, xformQuery.GetComponent(child.Value), xformQuery, pointQuery, spriteQuery, childSpriteOccluded, childLightOccluded);
+                    UpdateEntity(child.Value, TransformQuery.GetComponent(child.Value), childSpriteOccluded, childLightOccluded);
                 }
             }
             else
             {
                 while (childEnumerator.MoveNext(out var child))
                 {
-                    UpdateEntity(child.Value, xformQuery.GetComponent(child.Value), xformQuery, pointQuery, spriteQuery, spriteOccluded, lightOccluded);
+                    UpdateEntity(child.Value, TransformQuery.GetComponent(child.Value), spriteOccluded, lightOccluded);
                 }
             }
         }

Robust.Client/GameObjects/EntitySystems/InputSystem.cs

@@ -52,7 +52,7 @@ namespace Robust.Client.GameObjects
         /// <param name="message">Arguments for this event.</param>
         /// <param name="replay">if true, current cmd state will not be checked or updated - use this for "replaying" an
         /// old input that was saved or buffered until further processing could be done</param>
-        public bool HandleInputCommand(ICommonSession? session, BoundKeyFunction function, FullInputCmdMessage message, bool replay = false)
+        public bool HandleInputCommand(ICommonSession? session, BoundKeyFunction function, IFullInputCmdMessage message, bool replay = false)
         {
             #if DEBUG
 
@@ -78,14 +78,27 @@ namespace Robust.Client.GameObjects
                     continue;
 
                 // local handlers can block sending over the network.
-                if (handler.HandleCmdMessage(session, message))
+                if (handler.HandleCmdMessage(EntityManager, session, message))
                 {
                     return true;
                 }
             }
 
             // send it off to the server
-            DispatchInputCommand(message);
+            var clientMsg = (ClientFullInputCmdMessage)message;
+            var fullMsg = new FullInputCmdMessage(
+                clientMsg.Tick,
+                clientMsg.SubTick,
+                (int)clientMsg.InputSequence,
+                clientMsg.InputFunctionId,
+                clientMsg.State,
+                GetNetCoordinates(clientMsg.Coordinates),
+                clientMsg.ScreenCoordinates)
+            {
+                Uid = GetNetEntity(clientMsg.Uid)
+            };
+
+            DispatchInputCommand(clientMsg, fullMsg);
             return false;
         }
 
@@ -93,7 +106,7 @@ namespace Robust.Client.GameObjects
         /// Handle a predicted input command.
         /// </summary>
         /// <param name="inputCmd">Input command to handle as predicted.</param>
-        public void PredictInputCommand(FullInputCmdMessage inputCmd)
+        public void PredictInputCommand(IFullInputCmdMessage inputCmd)
         {
             DebugTools.AssertNotNull(_playerManager.LocalPlayer);
 
@@ -103,15 +116,16 @@ namespace Robust.Client.GameObjects
             var session = _playerManager.LocalPlayer!.Session;
             foreach (var handler in BindRegistry.GetHandlers(keyFunc))
             {
-                if (handler.HandleCmdMessage(session, inputCmd)) break;
+                if (handler.HandleCmdMessage(EntityManager, session, inputCmd))
+                    break;
             }
             Predicted = false;
 
         }
 
-        private void DispatchInputCommand(FullInputCmdMessage message)
+        private void DispatchInputCommand(ClientFullInputCmdMessage clientMsg, FullInputCmdMessage message)
         {
-            _stateManager.InputCommandDispatched(message);
+            _stateManager.InputCommandDispatched(clientMsg, message);
             EntityManager.EntityNetManager?.SendSystemNetworkMessage(message, message.InputSequence);
         }
 
@@ -152,7 +166,7 @@ namespace Robust.Client.GameObjects
             var funcId = _inputManager.NetworkBindMap.KeyFunctionID(keyFunction);
 
             var message = new FullInputCmdMessage(_timing.CurTick, _timing.TickFraction, funcId, state,
-                coords, new ScreenCoordinates(0, 0, default), EntityUid.Invalid);
+                GetNetCoordinates(coords), new ScreenCoordinates(0, 0, default), NetEntity.Invalid);
 
             HandleInputCommand(localPlayer.Session, keyFunction, message);
         }

Robust.Client/GameObjects/EntitySystems/UserInterfaceSystem.cs

@@ -43,7 +43,8 @@ namespace Robust.Client.GameObjects
 
         private void MessageReceived(BoundUIWrapMessage ev)
         {
-            var uid = ev.Entity;
+            var uid = GetEntity(ev.Entity);
+
             if (!TryComp<ClientUserInterfaceComponent>(uid, out var cmp))
                 return;
 
@@ -53,7 +54,7 @@ namespace Robust.Client.GameObjects
             if(_playerManager.LocalPlayer != null)
                 message.Session = _playerManager.LocalPlayer.Session;
 
-            message.Entity = uid;
+            message.Entity = GetNetEntity(uid);
             message.UiKey = uiKey;
 
             // Raise as object so the correct type is used.
@@ -125,7 +126,7 @@ namespace Robust.Client.GameObjects
 
         internal void SendUiMessage(BoundUserInterface bui, BoundUserInterfaceMessage msg)
         {
-            RaiseNetworkEvent(new BoundUIWrapMessage(bui.Owner, msg, bui.UiKey));
+            RaiseNetworkEvent(new BoundUIWrapMessage(GetNetEntity(bui.Owner), msg, bui.UiKey));
         }
     }
 }

Robust.Client/GameObjects/IClientEntityManagerInternal.cs

@@ -6,7 +6,7 @@ namespace Robust.Client.GameObjects
     {
         // These methods are used by the Game State Manager.
 
-        EntityUid CreateEntity(string? prototypeName, EntityUid uid = default);
+        EntityUid CreateEntity(string? prototypeName);
 
         void InitializeEntity(EntityUid entity, MetaDataComponent? meta = null);
 

Robust.Client/GameStates/ClientDirtySystem.cs

@@ -15,7 +15,7 @@ public sealed class ClientDirtySystem : EntitySystem
 {
     [Dependency] private readonly IClientGameTiming _timing = default!;
     [Dependency] private readonly IComponentFactory _compFact = default!;
-    
+
     // Entities that have removed networked components
     // could pool the ushort sets, but predicted component changes are rare... soo...
     internal readonly Dictionary<EntityUid, HashSet<ushort>> RemovedComponents = new();
@@ -40,11 +40,11 @@ public sealed class ClientDirtySystem : EntitySystem
 
     private void OnTerminate(ref EntityTerminatingEvent ev)
     {
-        if (!_timing.InPrediction || ev.Entity.IsClientSide())
+        if (!_timing.InPrediction || IsClientSide(ev.Entity))
             return;
 
         // Client-side entity deletion is not supported and will cause errors.
-        Logger.Error($"Predicting the deletion of a networked entity: {ToPrettyString(ev.Entity)}. Trace: {Environment.StackTrace}");
+        Log.Error($"Predicting the deletion of a networked entity: {ToPrettyString(ev.Entity)}. Trace: {Environment.StackTrace}");
     }
 
     private void OnCompRemoved(RemovedComponentEventArgs args)
@@ -52,8 +52,9 @@ public sealed class ClientDirtySystem : EntitySystem
         if (args.Terminating)
             return;
 
+        var uid = args.BaseArgs.Owner;
         var comp = args.BaseArgs.Component;
-        if (!_timing.InPrediction || comp.Owner.IsClientSide() || !comp.NetSyncEnabled)
+        if (!_timing.InPrediction || !comp.NetSyncEnabled || IsClientSide(uid))
             return;
 
         // Was this component added during prediction? If yes, then there is no need to re-add it when resetting.
@@ -62,7 +63,7 @@ public sealed class ClientDirtySystem : EntitySystem
 
         var netId = _compFact.GetRegistration(comp).NetID;
         if (netId != null)
-            RemovedComponents.GetOrNew(comp.Owner).Add(netId.Value);
+            RemovedComponents.GetOrNew(uid).Add(netId.Value);
     }
 
     public void Reset()
@@ -73,7 +74,7 @@ public sealed class ClientDirtySystem : EntitySystem
 
     private void OnEntityDirty(EntityUid e)
     {
-        if (_timing.InPrediction && !e.IsClientSide())
+        if (_timing.InPrediction && !IsClientSide(e))
             DirtyEntities.Add(e);
     }
 }

Robust.Client/GameStates/ClientGameStateManager.cs

@@ -47,8 +47,10 @@ namespace Robust.Client.GameStates
                 = new();
 
         // Game state dictionaries that get used every tick.
-        private readonly Dictionary<EntityUid, (bool EnteringPvs, GameTick LastApplied, EntityState? curState, EntityState?nextState)> _toApply = new();
-        private readonly Dictionary<EntityUid, EntityState> _toCreate = new();
+        private readonly Dictionary<EntityUid, (bool EnteringPvs, GameTick LastApplied, EntityState? curState, EntityState? nextState)> _toApply = new();
+        private readonly Dictionary<NetEntity, EntityState> _toCreate = new();
+        private readonly Dictionary<ushort, (IComponent Component, ComponentState? curState, ComponentState? nextState)> _compStateWork = new();
+        private readonly Dictionary<EntityUid, HashSet<Type>> _pendingReapplyNetStates = new();
 
         private uint _metaCompNetId;
 
@@ -157,7 +159,7 @@ namespace Robust.Client.GameStates
             }
         }
 
-        public void InputCommandDispatched(FullInputCmdMessage message)
+        public void InputCommandDispatched(ClientFullInputCmdMessage clientMessage, FullInputCmdMessage message)
         {
             if (!IsPredictionEnabled)
             {
@@ -201,7 +203,7 @@ namespace Robust.Client.GameStates
         public void UpdateFullRep(GameState state, bool cloneDelta = false)
             => _processor.UpdateFullRep(state, cloneDelta);
 
-        public Dictionary<EntityUid, Dictionary<ushort, ComponentState>> GetFullRep()
+        public Dictionary<NetEntity, Dictionary<ushort, ComponentState>> GetFullRep()
             => _processor.GetFullRep();
 
         private void HandlePvsLeaveMessage(MsgStateLeavePvs message)
@@ -210,7 +212,7 @@ namespace Robust.Client.GameStates
             PvsLeave?.Invoke(message);
         }
 
-        public void QueuePvsDetach(List<EntityUid> entities, GameTick tick)
+        public void QueuePvsDetach(List<NetEntity> entities, GameTick tick)
         {
             _processor.AddLeavePvsMessage(entities, tick);
             if (_replayRecording.IsRecording)
@@ -298,7 +300,7 @@ namespace Robust.Client.GameStates
                     _processor.UpdateFullRep(curState);
                 }
 
-                IEnumerable<EntityUid> createdEntities;
+                IEnumerable<NetEntity> createdEntities;
                 using (_prof.Group("ApplyGameState"))
                 {
                     if (_timing.LastProcessedTick < targetProcessedTick && nextState != null)
@@ -323,7 +325,7 @@ namespace Robust.Client.GameStates
                     catch (MissingMetadataException e)
                     {
                         // Something has gone wrong. Probably a missing meta-data component. Perhaps a full server state will fix it.
-                        RequestFullState(e.Uid);
+                        RequestFullState(e.NetEntity);
                         throw;
                     }
 #endif
@@ -392,10 +394,10 @@ namespace Robust.Client.GameStates
             }
         }
 
-        public void RequestFullState(EntityUid? missingEntity = null)
+        public void RequestFullState(NetEntity? missingEntity = null)
         {
             _sawmill.Info("Requesting full server state");
-            _network.ClientSendMessage(new MsgStateRequestFull { Tick = _timing.LastRealTick , MissingEntity = missingEntity ?? EntityUid.Invalid });
+            _network.ClientSendMessage(new MsgStateRequestFull { Tick = _timing.LastRealTick , MissingEntity = missingEntity ?? NetEntity.Invalid });
             _processor.RequestFullState();
         }
 
@@ -472,7 +474,7 @@ namespace Robust.Client.GameStates
 
             var countReset = 0;
             var system = _entitySystemManager.GetEntitySystem<ClientDirtySystem>();
-            var query = _entityManager.GetEntityQuery<MetaDataComponent>();
+            var metaQuery = _entityManager.GetEntityQuery<MetaDataComponent>();
             RemQueue<Component> toRemove = new();
 
             // This is terrible, and I hate it.
@@ -486,7 +488,8 @@ namespace Robust.Client.GameStates
                 if (_sawmill.Level <= LogLevel.Debug)
                     _sawmill.Debug($"Entity {entity} was made dirty.");
 
-                if (!_processor.TryGetLastServerStates(entity, out var last))
+                if (!metaQuery.TryGetComponent(entity, out var meta) ||
+                    !_processor.TryGetLastServerStates(meta.NetEntity, out var last))
                 {
                     // Entity was probably deleted on the server so do nothing.
                     continue;
@@ -564,7 +567,6 @@ namespace Robust.Client.GameStates
                     }
                 }
 
-                var meta = query.GetComponent(entity);
                 DebugTools.Assert(meta.EntityLastModifiedTick > _timing.LastRealTick);
                 meta.EntityLastModifiedTick = _timing.LastRealTick;
             }
@@ -588,15 +590,16 @@ namespace Robust.Client.GameStates
         ///     initial server state for any newly created entity. It does this by simply using the standard <see
         ///     cref="IEntityManager.GetComponentState(IEventBus, IComponent)"/>.
         /// </remarks>
-        private void MergeImplicitData(IEnumerable<EntityUid> createdEntities)
+        private void MergeImplicitData(IEnumerable<NetEntity> createdEntities)
         {
-            var outputData = new Dictionary<EntityUid, Dictionary<ushort, ComponentState>>();
+            var outputData = new Dictionary<NetEntity, Dictionary<ushort, ComponentState>>();
             var bus = _entityManager.EventBus;
 
-            foreach (var createdEntity in createdEntities)
+            foreach (var netEntity in createdEntities)
             {
+                var createdEntity = _entityManager.GetEntity(netEntity);
                 var compData = new Dictionary<ushort, ComponentState>();
-                outputData.Add(createdEntity, compData);
+                outputData.Add(netEntity, compData);
 
                 foreach (var (netId, component) in _entityManager.GetNetComponents(createdEntity))
                 {
@@ -617,7 +620,7 @@ namespace Robust.Client.GameStates
             _network.ClientSendMessage(new MsgStateAck() { Sequence = sequence });
         }
 
-        public IEnumerable<EntityUid> ApplyGameState(GameState curState, GameState? nextState)
+        public IEnumerable<NetEntity> ApplyGameState(GameState curState, GameState? nextState)
         {
             using var _ = _timing.StartStateApplicationArea();
 
@@ -637,7 +640,7 @@ namespace Robust.Client.GameStates
                 _config.TickProcessMessages();
             }
 
-            (IEnumerable<EntityUid> Created, List<EntityUid> Detached) output;
+            (IEnumerable<NetEntity> Created, List<NetEntity> Detached) output;
             using (_prof.Group("Entity"))
             {
                 output = ApplyEntityStates(curState, nextState);
@@ -656,7 +659,7 @@ namespace Robust.Client.GameStates
             return output.Created;
         }
 
-        private (IEnumerable<EntityUid> Created, List<EntityUid> Detached) ApplyEntityStates(GameState curState, GameState? nextState)
+        private (IEnumerable<NetEntity> Created, List<NetEntity> Detached) ApplyEntityStates(GameState curState, GameState? nextState)
         {
             var metas = _entities.GetEntityQuery<MetaDataComponent>();
             var xforms = _entities.GetEntityQuery<TransformComponent>();
@@ -665,6 +668,7 @@ namespace Robust.Client.GameStates
             var enteringPvs = 0;
             _toApply.Clear();
             _toCreate.Clear();
+            _pendingReapplyNetStates.Clear();
             var curSpan = curState.EntityStates.Span;
 
             // Create new entities
@@ -675,21 +679,40 @@ namespace Robust.Client.GameStates
 
                 foreach (var es in curSpan)
                 {
-                    if (metas.HasComponent(es.Uid))
+                    if (_entityManager.TryGetEntity(es.NetEntity, out var nUid))
+                    {
+                        DebugTools.Assert(_entityManager.EntityExists(nUid));
                         continue;
+                    }
 
                     count++;
-                    var uid = es.Uid;
                     var metaState = (MetaDataComponentState?)es.ComponentChanges.Value?.FirstOrDefault(c => c.NetID == _metaCompNetId).State;
                     if (metaState == null)
-                        throw new MissingMetadataException(uid);
+                        throw new MissingMetadataException(es.NetEntity);
 
-                    _entities.CreateEntity(metaState.PrototypeId, uid);
-                    _toCreate.Add(uid, es);
+                    var uid = _entities.CreateEntity(metaState.PrototypeId);
+                    _toCreate.Add(es.NetEntity, es);
                     _toApply.Add(uid, (false, GameTick.Zero, es, null));
 
                     var newMeta = metas.GetComponent(uid);
+
+                    // Client creates a client-side net entity for the newly created entity.
+                    // We need to clear this mapping before assigning the real net id.
+                    // TODO NetEntity Jank: prevent the client from creating this in the first place.
+                    _entityManager.ClearNetEntity(newMeta.NetEntity);
+
+                    _entityManager.SetNetEntity(uid, es.NetEntity, newMeta);
                     newMeta.LastStateApplied = curState.ToSequence;
+
+                    // Check if there's any component states awaiting this entity.
+                    if (_entityManager.PendingNetEntityStates.TryGetValue(es.NetEntity, out var value))
+                    {
+                        foreach (var (type, owner) in value)
+                        {
+                            var pending = _pendingReapplyNetStates.GetOrNew(owner);
+                            pending.Add(type);
+                        }
+                    }
                 }
 
                 _prof.WriteValue("Count", ProfData.Int32(count));
@@ -697,7 +720,9 @@ namespace Robust.Client.GameStates
 
             foreach (var es in curSpan)
             {
-                if (!metas.TryGetComponent(es.Uid, out var meta) || _toCreate.ContainsKey(es.Uid))
+                var uid = _entityManager.GetEntity(es.NetEntity);
+
+                if (!metas.TryGetComponent(uid, out var meta) || _toCreate.ContainsKey(es.NetEntity))
                 {
                     continue;
                 }
@@ -714,7 +739,7 @@ namespace Robust.Client.GameStates
                     continue;
                 }
 
-                _toApply.Add(es.Uid, (isEnteringPvs, meta.LastStateApplied, es, null));
+                _toApply.Add(uid, (isEnteringPvs, meta.LastStateApplied, es, null));
                 meta.LastStateApplied = curState.ToSequence;
             }
 
@@ -728,22 +753,31 @@ namespace Robust.Client.GameStates
             {
                 foreach (var es in nextState.EntityStates.Span)
                 {
-                    var uid = es.Uid;
-
-                    if (!metas.TryGetComponent(uid, out var meta))
+                    if (!_entityManager.TryGetEntity(es.NetEntity, out var uid))
                         continue;
 
+                    DebugTools.Assert(metas.HasComponent(uid));
+
                     // Does the next state actually have any future information about this entity that could be used for interpolation?
                     if (es.EntityLastModified != nextState.ToSequence)
                         continue;
 
-                    if (_toApply.TryGetValue(uid, out var state))
-                        _toApply[uid] = (state.EnteringPvs, state.LastApplied, state.curState, es);
+                    if (_toApply.TryGetValue(uid.Value, out var state))
+                        _toApply[uid.Value] = (state.EnteringPvs, state.LastApplied, state.curState, es);
                     else
-                        _toApply[uid] = (false, GameTick.Zero, null, es);
+                        _toApply[uid.Value] = (false, GameTick.Zero, null, es);
                 }
             }
 
+            // Check pending states and see if we need to force any entities to re-run component states.
+            foreach (var uid in _pendingReapplyNetStates.Keys)
+            {
+                if (_toApply.ContainsKey(uid))
+                    continue;
+
+                _toApply[uid] = (false, GameTick.Zero, null, null);
+            }
+
             var queuedBroadphaseUpdates = new List<(EntityUid, TransformComponent)>(enteringPvs);
 
             // Apply entity states.
@@ -766,6 +800,7 @@ namespace Robust.Client.GameStates
                     if (!_toApply.TryGetValue(xform.ParentUid, out var parent) || !parent.EnteringPvs)
                         queuedBroadphaseUpdates.Add((entity, xform));
                 }
+
                 _prof.WriteValue("Count", ProfData.Int32(_toApply.Count));
             }
 
@@ -829,37 +864,37 @@ namespace Robust.Client.GameStates
 
             // Construct hashset for set.Contains() checks.
             var entityStates = state.EntityStates.Span;
-            var stateEnts = new HashSet<EntityUid>(entityStates.Length);
+            var stateEnts = new HashSet<NetEntity>();
             foreach (var entState in entityStates)
             {
-                stateEnts.Add(entState.Uid);
+                stateEnts.Add(entState.NetEntity);
             }
 
-            var metas = _entities.GetEntityQuery<MetaDataComponent>();
             var xforms = _entities.GetEntityQuery<TransformComponent>();
             var xformSys = _entitySystemManager.GetEntitySystem<SharedTransformSystem>();
 
-            var currentEnts = _entities.GetEntities();
             var toDelete = new List<EntityUid>(Math.Max(64, _entities.EntityCount - stateEnts.Count));
-            foreach (var ent in currentEnts)
+
+            // Client side entities won't need the transform, but that should always be a tiny minority of entities
+            var metaQuery = _entityManager.AllEntityQueryEnumerator<MetaDataComponent, TransformComponent>();
+
+            while (metaQuery.MoveNext(out var ent, out var metadata, out var xform))
             {
-                if (ent.IsClientSide())
+                var netEnt = metadata.NetEntity;
+                if (metadata.NetEntity.IsClientSide())
                 {
                     if (deleteClientEntities)
                         toDelete.Add(ent);
                     continue;
                 }
 
-                if (stateEnts.Contains(ent) && metas.TryGetComponent(ent, out var meta))
+                if (stateEnts.Contains(netEnt))
                 {
-                    if (resetAllEntities || meta.LastStateApplied > state.ToSequence)
-                        meta.LastStateApplied = GameTick.Zero; // TODO track last-state-applied for individual components? Is it even worth it?
+                    if (resetAllEntities || metadata.LastStateApplied > state.ToSequence)
+                        metadata.LastStateApplied = GameTick.Zero; // TODO track last-state-applied for individual components? Is it even worth it?
                     continue;
                 }
 
-                if (!xforms.TryGetComponent(ent, out var xform))
-                    continue;
-
                 // This entity is going to get deleted, but maybe some if its children won't be, so lets detach them to
                 // null. First we will detach the parent in order to reduce the number of broadphase/lookup updates.
                 xformSys.DetachParentToNull(ent, xform);
@@ -872,7 +907,7 @@ namespace Robust.Client.GameStates
 
                     if (deleteClientChildren
                         && !deleteClientEntities // don't add duplicates
-                        && child.Value.IsClientSide())
+                        && _entities.IsClientSide(child.Value))
                     {
                         toDelete.Add(child.Value);
                     }
@@ -887,7 +922,7 @@ namespace Robust.Client.GameStates
         }
 
         private void ProcessDeletions(
-            ReadOnlySpan<EntityUid> delSpan,
+            ReadOnlySpan<NetEntity> delSpan,
             EntityQuery<TransformComponent> xforms,
             EntityQuery<MetaDataComponent> metas,
             SharedTransformSystem xformSys)
@@ -904,13 +939,19 @@ namespace Robust.Client.GameStates
 
             using var _ = _prof.Group("Deletion");
 
-            foreach (var id in delSpan)
+            foreach (var netEntity in delSpan)
             {
+                // Don't worry about this for later.
+                _entityManager.PendingNetEntityStates.Remove(netEntity);
+
+                if (!_entityManager.TryGetEntity(netEntity, out var id))
+                    continue;
+
                 if (!xforms.TryGetComponent(id, out var xform))
                     continue; // Already deleted? or never sent to us?
 
                 // First, a single recursive map change
-                xformSys.DetachParentToNull(id, xform);
+                xformSys.DetachParentToNull(id.Value, xform);
 
                 // Then detach all children.
                 var childEnumerator = xform.ChildEnumerator;
@@ -920,12 +961,12 @@ namespace Robust.Client.GameStates
                 }
 
                 // Finally, delete the entity.
-                _entities.DeleteEntity(id);
+                _entities.DeleteEntity(id.Value);
             }
             _prof.WriteValue("Count", ProfData.Int32(delSpan.Length));
         }
 
-        public void DetachImmediate(List<EntityUid> entities)
+        public void DetachImmediate(List<NetEntity> entities)
         {
             var metas = _entities.GetEntityQuery<MetaDataComponent>();
             var xforms = _entities.GetEntityQuery<TransformComponent>();
@@ -935,7 +976,7 @@ namespace Robust.Client.GameStates
             Detach(GameTick.MaxValue, null, entities, metas, xforms, xformSys, containerSys, lookupSys);
         }
 
-        private List<EntityUid> ProcessPvsDeparture(
+        private List<NetEntity> ProcessPvsDeparture(
             GameTick toTick,
             EntityQuery<MetaDataComponent> metas,
             EntityQuery<TransformComponent> xforms,
@@ -944,7 +985,7 @@ namespace Robust.Client.GameStates
             EntityLookupSystem lookupSys)
         {
             var toDetach = _processor.GetEntitiesToDetach(toTick, _pvsDetachBudget);
-            var detached = new List<EntityUid>();
+            var detached = new List<NetEntity>();
 
             if (toDetach.Count == 0)
                 return detached;
@@ -966,16 +1007,18 @@ namespace Robust.Client.GameStates
 
         private void Detach(GameTick maxTick,
             GameTick? lastStateApplied,
-            List<EntityUid> entities,
+            List<NetEntity> entities,
             EntityQuery<MetaDataComponent> metas,
             EntityQuery<TransformComponent> xforms,
             SharedTransformSystem xformSys,
             ContainerSystem containerSys,
             EntityLookupSystem lookupSys,
-            List<EntityUid>? detached = null)
+            List<NetEntity>? detached = null)
         {
-            foreach (var ent in entities)
+            foreach (var netEntity in entities)
             {
+                var ent = _entityManager.GetEntity(netEntity);
+
                 if (!metas.TryGetComponent(ent, out var meta))
                     continue;
 
@@ -1000,7 +1043,7 @@ namespace Robust.Client.GameStates
 
                     // In some cursed scenarios an entity inside of a container can leave PVS without the container itself leaving PVS.
                     // In those situations, we need to add the entity back to the list of expected entities after detaching.
-                    IContainer? container = null;
+                    BaseContainer? container = null;
                     if ((meta.Flags & MetaDataFlags.InContainer) != 0 &&
                         metas.TryGetComponent(xform.ParentUid, out var containerMeta) &&
                         (containerMeta.Flags & MetaDataFlags.Detached) == 0 &&
@@ -1014,35 +1057,38 @@ namespace Robust.Client.GameStates
                     DebugTools.Assert((meta.Flags & MetaDataFlags.InContainer) == 0);
 
                     if (container != null)
-                        containerSys.AddExpectedEntity(ent, container);
+                        containerSys.AddExpectedEntity(netEntity, container);
                 }
 
-                detached?.Add(ent);
+                detached?.Add(netEntity);
             }
         }
 
-        private void InitializeAndStart(Dictionary<EntityUid, EntityState> toCreate)
+        private void InitializeAndStart(Dictionary<NetEntity, EntityState> toCreate)
         {
+            var metaQuery = _entityManager.GetEntityQuery<MetaDataComponent>();
+
 #if EXCEPTION_TOLERANCE
-            HashSet<EntityUid> brokenEnts = new HashSet<EntityUid>();
+            var brokenEnts = new List<EntityUid>();
 #endif
             using (_prof.Group("Initialize Entity"))
             {
-                foreach (var entity in toCreate.Keys)
+                foreach (var netEntity in toCreate.Keys)
                 {
+                    var entity = _entityManager.GetEntity(netEntity);
 #if EXCEPTION_TOLERANCE
                     try
                     {
 #endif
-                    _entities.InitializeEntity(entity);
+                    _entities.InitializeEntity(entity, metaQuery.GetComponent(entity));
 #if EXCEPTION_TOLERANCE
                     }
                     catch (Exception e)
                     {
-                        _sawmill.Error($"Server entity threw in Init: ent={_entityManager.ToPrettyString(entity)}");
+                        _sawmill.Error($"Server entity threw in Init: ent={_entities.ToPrettyString(entity)}");
                         _runtimeLog.LogException(e, $"{nameof(ClientGameStateManager)}.{nameof(InitializeAndStart)}");
                         brokenEnts.Add(entity);
-                        toCreate.Remove(entity);
+                        toCreate.Remove(netEntity);
                     }
 #endif
                 }
@@ -1050,8 +1096,9 @@ namespace Robust.Client.GameStates
 
             using (_prof.Group("Start Entity"))
             {
-                foreach (var entity in toCreate.Keys)
+                foreach (var netEntity in toCreate.Keys)
                 {
+                    var entity = _entityManager.GetEntity(netEntity);
 #if EXCEPTION_TOLERANCE
                     try
                     {
@@ -1064,7 +1111,7 @@ namespace Robust.Client.GameStates
                         _sawmill.Error($"Server entity threw in Start: ent={_entityManager.ToPrettyString(entity)}");
                         _runtimeLog.LogException(e, $"{nameof(ClientGameStateManager)}.{nameof(InitializeAndStart)}");
                         brokenEnts.Add(entity);
-                        toCreate.Remove(entity);
+                        toCreate.Remove(netEntity);
                     }
 #endif
                 }
@@ -1081,8 +1128,9 @@ namespace Robust.Client.GameStates
         private void HandleEntityState(EntityUid uid, IEventBus bus, EntityState? curState,
             EntityState? nextState, GameTick lastApplied, GameTick toTick, bool enteringPvs)
         {
-            var size = (curState?.ComponentChanges.Span.Length ?? 0) + (nextState?.ComponentChanges.Span.Length ?? 0);
-            var compStateWork = new Dictionary<ushort, (IComponent Component, ComponentState? curState, ComponentState? nextState)>(size);
+            _compStateWork.Clear();
+            var meta = _entityManager.GetComponent<MetaDataComponent>(uid);
+            var netEntity = meta.NetEntity;
 
             // First remove any deleted components
             if (curState?.NetComponents != null)
@@ -1107,7 +1155,7 @@ namespace Robust.Client.GameStates
                 //
                 // as to why we need to reset: because in the process of detaching to null-space, we will have dirtied
                 // the entity. most notably, all entities will have been ejected from their containers.
-                foreach (var (id, state) in _processor.GetLastServerStates(uid))
+                foreach (var (id, state) in _processor.GetLastServerStates(netEntity))
                 {
                     if (!_entityManager.TryGetComponent(uid, id, out var comp))
                     {
@@ -1117,7 +1165,7 @@ namespace Robust.Client.GameStates
                         _entityManager.AddComponent(uid, newComp, true);
                     }
 
-                    compStateWork[id] = (comp, state, null);
+                    _compStateWork[id] = (comp, state, null);
                 }
             }
             else if (curState != null)
@@ -1134,7 +1182,7 @@ namespace Robust.Client.GameStates
                     else if (compChange.LastModifiedTick <= lastApplied && lastApplied != GameTick.Zero)
                         continue;
 
-                    compStateWork[compChange.NetID] = (comp, compChange.State, null);
+                    _compStateWork[compChange.NetID] = (comp, compChange.State, null);
                 }
             }
 
@@ -1152,14 +1200,38 @@ namespace Robust.Client.GameStates
                         continue;
                     }
 
-                    if (compStateWork.TryGetValue(compState.NetID, out var state))
-                        compStateWork[compState.NetID] = (comp, state.curState, compState.State);
+                    if (_compStateWork.TryGetValue(compState.NetID, out var state))
+                        _compStateWork[compState.NetID] = (comp, state.curState, compState.State);
                     else
-                        compStateWork[compState.NetID] = (comp, null, compState.State);
+                        _compStateWork[compState.NetID] = (comp, null, compState.State);
                 }
             }
 
-            foreach (var (comp, cur, next) in compStateWork.Values)
+            // If we have a NetEntity we reference come in then apply their state.
+            if (_pendingReapplyNetStates.TryGetValue(uid, out var reapplyTypes))
+            {
+                var lastState = _processor.GetLastServerStates(netEntity);
+
+                foreach (var type in reapplyTypes)
+                {
+                    var compRef = _compFactory.GetRegistration(type);
+                    var netId = compRef.NetID;
+
+                    if (netId == null)
+                        continue;
+
+                    if (_compStateWork.ContainsKey(netId.Value) ||
+                        !_entityManager.TryGetComponent(uid, type, out var comp) ||
+                        !lastState.TryGetValue(netId.Value, out var lastCompState))
+                    {
+                        continue;
+                    }
+
+                    _compStateWork[netId.Value] = (comp, lastCompState, null);
+                }
+            }
+
+            foreach (var (comp, cur, next) in _compStateWork.Values)
             {
                 try
                 {
@@ -1180,6 +1252,7 @@ namespace Robust.Client.GameStates
         }
 
         #region Debug Commands
+
         private bool TryParseUid(IConsoleShell shell, string[] args, out EntityUid uid, [NotNullWhen(true)] out MetaDataComponent? meta)
         {
             if (args.Length != 1)
@@ -1238,7 +1311,7 @@ namespace Robust.Client.GameStates
             var xform = _entities.GetComponent<TransformComponent>(uid);
             if (xform.ParentUid.IsValid())
             {
-                IContainer? container = null;
+                BaseContainer? container = null;
                 if ((meta.Flags & MetaDataFlags.InContainer) != 0 &&
                     _entities.TryGetComponent(xform.ParentUid, out MetaDataComponent? containerMeta) &&
                     (containerMeta.Flags & MetaDataFlags.Detached) == 0)
@@ -1249,7 +1322,7 @@ namespace Robust.Client.GameStates
                 _entities.EntitySysManager.GetEntitySystem<TransformSystem>().DetachParentToNull(uid, xform);
 
                 if (container != null)
-                    containerSys.AddExpectedEntity(uid, container);
+                    containerSys.AddExpectedEntity(_entities.GetNetEntity(uid), container);
             }
         }
 
@@ -1266,18 +1339,21 @@ namespace Robust.Client.GameStates
 
             // If this is not a client-side entity, it also needs to be removed from the full-server state dictionary to
             // avoid errors. This has to be done recursively for all children.
-            void _recursiveRemoveState(TransformComponent xform, EntityQuery<TransformComponent> query)
+            void _recursiveRemoveState(NetEntity netEntity, TransformComponent xform, EntityQuery<MetaDataComponent> metaQuery, EntityQuery<TransformComponent> xformQuery)
             {
-                _processor._lastStateFullRep.Remove(xform.Owner);
+                _processor._lastStateFullRep.Remove(netEntity);
                 foreach (var child in xform.ChildEntities)
                 {
-                    if (query.TryGetComponent(child, out var childXform))
-                        _recursiveRemoveState(childXform, query);
+                    if (xformQuery.TryGetComponent(child, out var childXform) &&
+                        metaQuery.TryGetComponent(child, out var childMeta))
+                    {
+                        _recursiveRemoveState(childMeta.NetEntity, childXform, metaQuery, xformQuery);
+                    }
                 }
             }
 
-            if (!uid.IsClientSide() && _entities.TryGetComponent(uid, out TransformComponent? xform))
-                _recursiveRemoveState(xform, _entities.GetEntityQuery<TransformComponent>());
+            if (!_entities.IsClientSide(uid) && _entities.TryGetComponent(uid, out TransformComponent? xform))
+                _recursiveRemoveState(meta.NetEntity, xform, _entities.GetEntityQuery<MetaDataComponent>(), _entities.GetEntityQuery<TransformComponent>());
 
             // Set ApplyingState to true to avoid logging errors about predicting the deletion of networked entities.
             using (_timing.StartStateApplicationArea())
@@ -1311,7 +1387,7 @@ namespace Robust.Client.GameStates
 
             meta.Flags &= ~MetaDataFlags.Detached;
 
-            if (!_processor.TryGetLastServerStates(uid, out var lastState))
+            if (!_processor.TryGetLastServerStates(meta.NetEntity, out var lastState))
                 return;
 
             foreach (var (id, state) in lastState)
@@ -1352,9 +1428,9 @@ namespace Robust.Client.GameStates
     public sealed class GameStateAppliedArgs : EventArgs
     {
         public GameState AppliedState { get; }
-        public readonly List<EntityUid> Detached;
+        public readonly List<NetEntity> Detached;
 
-        public GameStateAppliedArgs(GameState appliedState, List<EntityUid> detached)
+        public GameStateAppliedArgs(GameState appliedState, List<NetEntity> detached)
         {
             AppliedState = appliedState;
             Detached = detached;
@@ -1363,12 +1439,12 @@ namespace Robust.Client.GameStates
 
     public sealed class MissingMetadataException : Exception
     {
-        public readonly EntityUid Uid;
+        public readonly NetEntity NetEntity;
 
-        public MissingMetadataException(EntityUid uid)
-            : base($"Server state is missing the metadata component for a new entity: {uid}.")
+        public MissingMetadataException(NetEntity netEntity)
+            : base($"Server state is missing the metadata component for a new entity: {netEntity}.")
         {
-            Uid = uid;
+            NetEntity = netEntity;
         }
     }
 }

Robust.Client/GameStates/GameStateProcessor.cs

@@ -20,7 +20,7 @@ namespace Robust.Client.GameStates
 
         private readonly List<GameState> _stateBuffer = new();
 
-        private readonly Dictionary<GameTick, List<EntityUid>> _pvsDetachMessages = new();
+        private readonly Dictionary<GameTick, List<NetEntity>> _pvsDetachMessages = new();
 
         private ISawmill _logger = default!;
         private ISawmill _stateLogger = default!;
@@ -44,7 +44,7 @@ namespace Robust.Client.GameStates
         /// <summary>
         /// This dictionary stores the full most recently received server state of any entity. This is used whenever predicted entities get reset.
         /// </summary>
-        internal readonly Dictionary<EntityUid, Dictionary<ushort, ComponentState>> _lastStateFullRep
+        internal readonly Dictionary<NetEntity, Dictionary<ushort, ComponentState>> _lastStateFullRep
             = new();
 
         /// <inheritdoc />
@@ -178,10 +178,10 @@ namespace Robust.Client.GameStates
 
             foreach (var entityState in state.EntityStates.Span)
             {
-                if (!_lastStateFullRep.TryGetValue(entityState.Uid, out var compData))
+                if (!_lastStateFullRep.TryGetValue(entityState.NetEntity, out var compData))
                 {
                     compData = new Dictionary<ushort, ComponentState>();
-                    _lastStateFullRep.Add(entityState.Uid, compData);
+                    _lastStateFullRep.Add(entityState.NetEntity, compData);
                 }
 
                 foreach (var change in entityState.ComponentChanges.Span)
@@ -263,7 +263,7 @@ namespace Robust.Client.GameStates
             return false;
         }
 
-        internal void AddLeavePvsMessage(List<EntityUid> entities, GameTick tick)
+        internal void AddLeavePvsMessage(List<NetEntity> entities, GameTick tick)
         {
             // Late message may still need to be processed,
             DebugTools.Assert(entities.Count > 0);
@@ -272,9 +272,9 @@ namespace Robust.Client.GameStates
 
         public void ClearDetachQueue() => _pvsDetachMessages.Clear();
 
-        public List<(GameTick Tick, List<EntityUid> Entities)> GetEntitiesToDetach(GameTick toTick, int budget)
+        public List<(GameTick Tick, List<NetEntity> Entities)> GetEntitiesToDetach(GameTick toTick, int budget)
         {
-            var result = new List<(GameTick Tick, List<EntityUid> Entities)>();
+            var result = new List<(GameTick Tick, List<NetEntity> Entities)>();
             foreach (var (tick, entities) in _pvsDetachMessages)
             {
                 if (tick > toTick)
@@ -353,11 +353,11 @@ namespace Robust.Client.GameStates
             LastFullStateRequested = _timing.LastRealTick;
         }
 
-        public void MergeImplicitData(Dictionary<EntityUid, Dictionary<ushort, ComponentState>> implicitData)
+        public void MergeImplicitData(Dictionary<NetEntity, Dictionary<ushort, ComponentState>> implicitData)
         {
-            foreach (var (uid, implicitEntState) in implicitData)
+            foreach (var (netEntity, implicitEntState) in implicitData)
             {
-                var fullRep = _lastStateFullRep[uid];
+                var fullRep = _lastStateFullRep[netEntity];
 
                 foreach (var (netId, implicitCompState) in implicitEntState)
                 {
@@ -374,7 +374,7 @@ namespace Robust.Client.GameStates
                     // state from the entity prototype.
                     if (implicitCompState is not IComponentDeltaState implicitDelta || !implicitDelta.FullState)
                     {
-                        _logger.Error($"Server sent delta state and client failed to construct an implicit full state for entity {uid}");
+                        _logger.Error($"Server sent delta state and client failed to construct an implicit full state for entity {netEntity}");
                         continue;
                     }
 
@@ -385,17 +385,17 @@ namespace Robust.Client.GameStates
             }
         }
 
-        public Dictionary<ushort, ComponentState> GetLastServerStates(EntityUid entity)
+        public Dictionary<ushort, ComponentState> GetLastServerStates(NetEntity netEntity)
         {
-            return _lastStateFullRep[entity];
+            return _lastStateFullRep[netEntity];
         }
 
-        public Dictionary<EntityUid, Dictionary<ushort, ComponentState>> GetFullRep()
+        public Dictionary<NetEntity, Dictionary<ushort, ComponentState>> GetFullRep()
         {
             return _lastStateFullRep;
         }
 
-        public bool TryGetLastServerStates(EntityUid entity,
+        public bool TryGetLastServerStates(NetEntity entity,
             [NotNullWhen(true)] out Dictionary<ushort, ComponentState>? dictionary)
         {
             return _lastStateFullRep.TryGetValue(entity, out dictionary);

Robust.Client/GameStates/IClientGameStateManager.cs

@@ -75,7 +75,7 @@ namespace Robust.Client.GameStates
         /// <summary>
         ///     Applies a given set of game states.
         /// </summary>
-        IEnumerable<EntityUid> ApplyGameState(GameState curState, GameState? nextState);
+        IEnumerable<NetEntity> ApplyGameState(GameState curState, GameState? nextState);
 
         /// <summary>
         ///     Resets any entities that have changed while predicting future ticks.
@@ -86,12 +86,12 @@ namespace Robust.Client.GameStates
         ///     An input command has been dispatched.
         /// </summary>
         /// <param name="message">Message being dispatched.</param>
-        void InputCommandDispatched(FullInputCmdMessage message);
+        void InputCommandDispatched(ClientFullInputCmdMessage clientMsg, FullInputCmdMessage message);
 
         /// <summary>
         ///     Requests a full state from the server. This should override even implicit entity data.
         /// </summary>
-        void RequestFullState(EntityUid? missingEntity = null);
+        void RequestFullState(NetEntity? missingEntity = null);
 
         uint SystemMessageDispatched<T>(T message) where T : EntityEventArgs;
 
@@ -105,7 +105,7 @@ namespace Robust.Client.GameStates
         /// <summary>
         /// Returns the full collection of cached game states that are used to reset predicted entities.
         /// </summary>
-        Dictionary<EntityUid, Dictionary<ushort, ComponentState>> GetFullRep();
+        Dictionary<NetEntity, Dictionary<ushort, ComponentState>> GetFullRep();
 
         /// <summary>
         /// This will perform some setup in order to reset the game to an earlier state. To fully reset the state
@@ -144,12 +144,12 @@ namespace Robust.Client.GameStates
         /// Queue a collection of entities that are to be detached to null-space & marked as PVS-detached.
         /// This store and modify the list given to it.
         /// </summary>
-        void QueuePvsDetach(List<EntityUid> entities, GameTick tick);
+        void QueuePvsDetach(List<NetEntity> entities, GameTick tick);
 
         /// <summary>
         /// Immediately detach several entities.
         /// </summary>
-        void DetachImmediate(List<EntityUid> entities);
+        void DetachImmediate(List<NetEntity> entities);
 
         /// <summary>
         /// Clears the PVS detach queue.

Robust.Client/GameStates/IGameStateProcessor.cs

@@ -83,13 +83,13 @@ namespace Robust.Client.GameStates
         ///     The data to merge.
         ///     It's a dictionary of entity ID -> (component net ID -> ComponentState)
         /// </param>
-        void MergeImplicitData(Dictionary<EntityUid, Dictionary<ushort, ComponentState>> data);
+        void MergeImplicitData(Dictionary<NetEntity, Dictionary<ushort, ComponentState>> data);
 
         /// <summary>
         ///     Get the last state data from the server for an entity.
         /// </summary>
         /// <returns>Dictionary (net ID -> ComponentState)</returns>
-        Dictionary<ushort, ComponentState> GetLastServerStates(EntityUid entity);
+        Dictionary<ushort, ComponentState> GetLastServerStates(NetEntity entity);
 
         /// <summary>
         ///     Calculate the number of applicable states in the game state buffer from a given tick.
@@ -98,7 +98,7 @@ namespace Robust.Client.GameStates
         /// <param name="fromTick">The tick to calculate from.</param>
         int CalculateBufferSize(GameTick fromTick);
 
-        bool TryGetLastServerStates(EntityUid entity,
+        bool TryGetLastServerStates(NetEntity entity,
             [NotNullWhen(true)] out Dictionary<ushort, ComponentState>? dictionary);
     }
 }

Robust.Client/GameStates/NetEntityOverlay.cs

@@ -35,7 +35,7 @@ namespace Robust.Client.GameStates
 
         private readonly Font _font;
         private readonly int _lineHeight;
-        private readonly Dictionary<EntityUid, NetEntData> _netEnts = new();
+        private readonly Dictionary<NetEntity, NetEntData> _netEnts = new();
 
         public NetEntityOverlay()
         {
@@ -77,12 +77,12 @@ namespace Robust.Client.GameStates
 
             foreach (var entityState in gameState.EntityStates.Span)
             {
-                if (!_netEnts.TryGetValue(entityState.Uid, out var netEnt))
+                if (!_netEnts.TryGetValue(entityState.NetEntity, out var netEnt))
                 {
                     if (_netEnts.Count >= _maxEnts)
                         continue;
 
-                    _netEnts[entityState.Uid] = netEnt = new();
+                    _netEnts[entityState.NetEntity] = netEnt = new();
                 }
 
                 if (!netEnt.InPVS && netEnt.LastUpdate < gameState.ToSequence)
@@ -119,11 +119,13 @@ namespace Robust.Client.GameStates
             var screenHandle = args.ScreenHandle;
 
             int i = 0;
-            foreach (var (uid, netEnt) in _netEnts)
+            foreach (var (nent, netEnt) in _netEnts)
             {
+                var uid = _entityManager.GetEntity(nent);
+
                 if (!_entityManager.EntityExists(uid))
                 {
-                    _netEnts.Remove(uid);
+                    _netEnts.Remove(nent);
                     continue;
                 }
 

Robust.Client/GameStates/NetGraphOverlay.cs

@@ -26,6 +26,7 @@ namespace Robust.Client.GameStates
         [Dependency] private readonly IClientNetManager _netManager = default!;
         [Dependency] private readonly IClientGameStateManager _gameStateManager = default!;
         [Dependency] private readonly IComponentFactory _componentFactory = default!;
+        [Dependency] private readonly IEntityManager _entManager = default!;
 
         private const int HistorySize = 60 * 5; // number of ticks to keep in history.
         private const int TargetPayloadBps = 56000 / 8; // Target Payload size in Bytes per second. A mind-numbing fifty-six thousand bits per second, who would ever need more?
@@ -73,7 +74,7 @@ namespace Robust.Client.GameStates
             _history.Add((toSeq, sz, lag, buffer));
 
             // not watching an ent
-            if(!WatchEntId.IsValid() || WatchEntId.IsClientSide())
+            if(!WatchEntId.IsValid() || _entManager.IsClientSide(WatchEntId))
                 return;
 
             string? entStateString = null;
@@ -86,7 +87,9 @@ namespace Robust.Client.GameStates
                 var sb = new StringBuilder();
                 foreach (var entState in entStates.Span)
                 {
-                    if (entState.Uid != WatchEntId)
+                    var uid = _entManager.GetEntity(entState.NetEntity);
+
+                    if (uid != WatchEntId)
                         continue;
 
                     if (!entState.ComponentChanges.HasContents)
@@ -115,7 +118,9 @@ namespace Robust.Client.GameStates
 
             foreach (var ent in args.Detached)
             {
-                if (ent != WatchEntId)
+                var uid = _entManager.GetEntity(ent);
+
+                if (uid != WatchEntId)
                     continue;
 
                 conShell.WriteLine($"watchEnt: Left PVS at tick {args.AppliedState.ToSequence}, eid={WatchEntId}" + "\n");
@@ -126,7 +131,9 @@ namespace Robust.Client.GameStates
             {
                 foreach (var entDelete in entDeletes.Span)
                 {
-                    if (entDelete == WatchEntId)
+                    var uid = _entManager.GetEntity(entDelete);
+
+                    if (uid == WatchEntId)
                         entDelString = "\n  Deleted";
                 }
             }
@@ -294,30 +301,33 @@ namespace Robust.Client.GameStates
 
         private sealed class NetWatchEntCommand : LocalizedCommands
         {
+            [Dependency] private readonly IEntityManager _entManager = default!;
+            [Dependency] private readonly IOverlayManager _overlayManager = default!;
+            [Dependency] private readonly IPlayerManager _playerManager = default!;
+
             public override string Command => "net_watchent";
 
             public override void Execute(IConsoleShell shell, string argStr, string[] args)
             {
-                EntityUid eValue;
+                EntityUid? entity;
+
                 if (args.Length == 0)
                 {
-                    eValue = IoCManager.Resolve<IPlayerManager>().LocalPlayer?.ControlledEntity ?? EntityUid.Invalid;
+                    entity = _playerManager.LocalPlayer?.ControlledEntity ?? EntityUid.Invalid;
                 }
-                else if (!EntityUid.TryParse(args[0], out eValue))
+                else if (!NetEntity.TryParse(args[0], out var netEntity) || !_entManager.TryGetEntity(netEntity, out entity))
                 {
                     shell.WriteError("Invalid argument: Needs to be 0 or an entityId.");
                     return;
                 }
 
-                var overlayMan = IoCManager.Resolve<IOverlayManager>();
-
-                if (!overlayMan.TryGetOverlay(out NetGraphOverlay? overlay))
+                if (!_overlayManager.TryGetOverlay(out NetGraphOverlay? overlay))
                 {
-                    overlay = new();
-                    overlayMan.AddOverlay(overlay);
+                    overlay = new NetGraphOverlay();
+                    _overlayManager.AddOverlay(overlay);
                 }
 
-                overlay.WatchEntId = eValue;
+                overlay.WatchEntId = entity.Value;
             }
         }
     }

Robust.Client/Physics/GridFixtureSystem.cs

@@ -62,8 +62,9 @@ namespace Robust.Client.Physics
             Log.Info($"Received grid fixture debug data");
             if (!_enableDebug) return;
 
-            _nodes[ev.Grid] = ev.Nodes;
-            _connections[ev.Grid] = ev.Connections;
+            var grid = GetEntity(ev.Grid);
+            _nodes[grid] = ev.Nodes;
+            _connections[grid] = ev.Connections;
         }
 
         private sealed class GridSplitNodeOverlay : Overlay

Robust.Client/Physics/JointSystem.cs

@@ -20,7 +20,7 @@ namespace Robust.Client.Physics
         {
             if (args.Current is not JointComponentState jointState) return;
 
-            component.Relay = jointState.Relay;
+            component.Relay = EnsureEntity<JointComponent>(jointState.Relay, uid);
 
             // Initial state gets applied before the entity (& entity's transform) have been initialized.
             // So just let joint init code handle that.
@@ -29,7 +29,7 @@ namespace Robust.Client.Physics
                 component.Joints.Clear();
                 foreach (var (id, state) in jointState.Joints)
                 {
-                    component.Joints[id] = state.GetJoint();
+                    component.Joints[id] = state.GetJoint(EntityManager, uid);
                 }
                 return;
             }
@@ -62,8 +62,8 @@ namespace Robust.Client.Physics
                     continue;
                 }
 
-                var other = state.UidA == uid ? state.UidB : state.UidA;
-
+                var uidA = GetEntity(state.UidA);
+                var other = uidA == uid ? GetEntity(state.UidB) : uidA;
 
                 // Add new joint (if possible).
                 // Need to wait for BOTH joint components to come in first before we can add it. Yay dependencies!
@@ -82,11 +82,11 @@ namespace Robust.Client.Physics
                 // TODO: component state handling ordering.
                 if (Transform(uid).MapID == MapId.Nullspace)
                 {
-                    AddedJoints.Add(state.GetJoint());
+                    AddedJoints.Add(state.GetJoint(EntityManager, uid));
                     continue;
                 }
 
-                AddJoint(state.GetJoint());
+                AddJoint(state.GetJoint(EntityManager, uid));
             }
         }
     }

Robust.Client/Placement/PlacementManager.cs

@@ -225,7 +225,7 @@ namespace Robust.Client.Placement
                         }
                     }))
                 .Bind(EngineKeyFunctions.EditorPlaceObject, new PointerStateInputCmdHandler(
-                    (session, coords, uid) =>
+                    (session, netCoords, nent) =>
                     {
                         if (!IsActive)
                             return false;
@@ -239,15 +239,15 @@ namespace Robust.Client.Placement
 
                         if (Eraser)
                         {
-                            if (HandleDeletion(coords))
+                            if (HandleDeletion(netCoords))
                                 return true;
 
-                            if (uid == EntityUid.Invalid)
+                            if (nent == EntityUid.Invalid)
                             {
                                 return false;
                             }
 
-                            HandleDeletion(uid);
+                            HandleDeletion(nent);
                         }
                         else
                         {
@@ -428,7 +428,7 @@ namespace Robust.Client.Placement
 
             var msg = new MsgPlacement();
             msg.PlaceType = PlacementManagerMessage.RequestEntRemove;
-            msg.EntityUid = entity;
+            msg.EntityUid = EntityManager.GetNetEntity(entity);
             _networkManager.ClientSendMessage(msg);
         }
 
@@ -436,7 +436,7 @@ namespace Robust.Client.Placement
         {
             var msg = new MsgPlacement();
             msg.PlaceType = PlacementManagerMessage.RequestRectRemove;
-            msg.EntityCoordinates = new EntityCoordinates(StartPoint.EntityId, rect.BottomLeft);
+            msg.NetCoordinates = new NetCoordinates(EntityManager.GetNetEntity(StartPoint.EntityId), rect.BottomLeft);
             msg.RectSize = rect.Size;
             _networkManager.ClientSendMessage(msg);
         }
@@ -790,7 +790,7 @@ namespace Robust.Client.Placement
                 message.EntityTemplateName = CurrentPermission.EntityType;
 
             // world x and y
-            message.EntityCoordinates = coordinates;
+            message.NetCoordinates = EntityManager.GetNetCoordinates(coordinates);
 
             message.DirRcv = Direction;
 

Robust.Client/Player/PlayerManager.cs

@@ -6,6 +6,7 @@ using Robust.Shared.Enums;
 using Robust.Shared.GameObjects;
 using Robust.Shared.GameStates;
 using Robust.Shared.IoC;
+using Robust.Shared.Log;
 using Robust.Shared.Network;
 using Robust.Shared.Network.Messages;
 using Robust.Shared.Players;
@@ -24,6 +25,7 @@ namespace Robust.Client.Player
         [Dependency] private readonly IClientNetManager _network = default!;
         [Dependency] private readonly IBaseClient _client = default!;
         [Dependency] private readonly IEntityManager _entManager = default!;
+        [Dependency] private readonly ILogManager _logMan = default!;
 
         /// <summary>
         ///     Active sessions of connected clients to the server.
@@ -65,6 +67,8 @@ namespace Robust.Client.Player
             }
         }
         private LocalPlayer? _localPlayer;
+        private ISawmill _sawmill = default!;
+
         public event Action<LocalPlayerChangedEventArgs>? LocalPlayerChanged;
 
         /// <inheritdoc />
@@ -82,6 +86,7 @@ namespace Robust.Client.Player
         {
             _client.RunLevelChanged += OnRunLevelChanged;
 
+            _sawmill = _logMan.GetSawmill("player");
             _network.RegisterNetMessage<MsgPlayerListReq>();
             _network.RegisterNetMessage<MsgPlayerList>(HandlePlayerList);
         }
@@ -122,7 +127,13 @@ namespace Robust.Client.Player
 
             if (myState != null)
             {
-                UpdateAttachedEntity(myState.ControlledEntity);
+                var uid = _entManager.GetEntity(myState.ControlledEntity);
+                if (myState.ControlledEntity is {Valid: true} && !_entManager.EntityExists(uid))
+                {
+                    _sawmill.Error($"Received player state for local player with an unknown net entity!");
+                }
+
+                UpdateAttachedEntity(uid);
                 UpdateSessionStatus(myState.Status);
             }
 
@@ -181,11 +192,13 @@ namespace Robust.Client.Player
                 if (_sessions.TryGetValue(state.UserId, out var session))
                 {
                     var local = (PlayerSession) session;
+                    var controlled = _entManager.GetEntity(state.ControlledEntity);
+
                     // Exists, update data.
                     if (local.Name == state.Name
                         && local.Status == state.Status
                         && local.Ping == state.Ping
-                        && local.AttachedEntity == state.ControlledEntity)
+                        && local.AttachedEntity == controlled)
                     {
                         continue;
                     }
@@ -194,7 +207,7 @@ namespace Robust.Client.Player
                     local.Name = state.Name;
                     local.Status = state.Status;
                     local.Ping = state.Ping;
-                    local.AttachedEntity = state.ControlledEntity;
+                    local.AttachedEntity = controlled;
                 }
                 else
                 {
@@ -206,7 +219,7 @@ namespace Robust.Client.Player
                         Name = state.Name,
                         Status = state.Status,
                         Ping = state.Ping,
-                        AttachedEntity = state.ControlledEntity,
+                        AttachedEntity = _entManager.GetEntity(state.ControlledEntity),
                     };
                     _sessions.Add(state.UserId, newSession);
                     if (state.UserId == LocalPlayer!.UserId)

Robust.Client/Replays/Loading/ReplayLoadManager.Checkpoints.cs

@@ -83,8 +83,8 @@ public sealed partial class ReplayLoadManager
         }
 
         HashSet<ResPath> uploadedFiles = new();
-        var detached = new HashSet<EntityUid>();
-        var detachQueue = new Dictionary<GameTick, List<EntityUid>>();
+        var detached = new HashSet<NetEntity>();
+        var detachQueue = new Dictionary<GameTick, List<NetEntity>>();
 
         if (initMessages != null)
             UpdateMessages(initMessages, uploadedFiles, prototypes, cvars, detachQueue, ref timeBase, true);
@@ -92,11 +92,11 @@ public sealed partial class ReplayLoadManager
         ProcessQueue(GameTick.MaxValue, detachQueue, detached);
 
         var entSpan = state0.EntityStates.Value;
-        Dictionary<EntityUid, EntityState> entStates = new(entSpan.Count);
+        Dictionary<NetEntity, EntityState> entStates = new(entSpan.Count);
         foreach (var entState in entSpan)
         {
             var modifiedState = AddImplicitData(entState);
-            entStates.Add(entState.Uid, modifiedState);
+            entStates.Add(entState.NetEntity, modifiedState);
         }
 
         await callback(0, states.Count, LoadingState.ProcessingFiles, true);
@@ -112,11 +112,11 @@ public sealed partial class ReplayLoadManager
             default,
             entStates.Values.ToArray(),
             playerStates.Values.ToArray(),
-            Array.Empty<EntityUid>());
+            Array.Empty<NetEntity>());
         checkPoints.Add(new CheckpointState(state0, timeBase, cvars, 0, detached));
 
         DebugTools.Assert(state0.EntityDeletions.Value.Count == 0);
-        var empty = Array.Empty<EntityUid>();
+        var empty = Array.Empty<NetEntity>();
 
         TimeSpan GetTime(GameTick tick)
         {
@@ -176,8 +176,8 @@ public sealed partial class ReplayLoadManager
 
     private void ProcessQueue(
         GameTick curTick,
-        Dictionary<GameTick, List<EntityUid>> detachQueue,
-        HashSet<EntityUid> detached)
+        Dictionary<GameTick, List<NetEntity>> detachQueue,
+        HashSet<NetEntity> detached)
     {
         foreach (var (tick, ents) in detachQueue)
         {
@@ -192,7 +192,7 @@ public sealed partial class ReplayLoadManager
         HashSet<ResPath> uploadedFiles,
         Dictionary<Type, HashSet<string>> prototypes,
         Dictionary<string, object> cvars,
-        Dictionary<GameTick, List<EntityUid>> detachQueue,
+        Dictionary<GameTick, List<NetEntity>> detachQueue,
         ref (TimeSpan, GameTick) timeBase,
         bool ignoreDuplicates = false)
     {
@@ -301,8 +301,8 @@ public sealed partial class ReplayLoadManager
         _locMan.ReloadLocalizations();
     }
 
-    private void UpdateDeletions(NetListAsArray<EntityUid> entityDeletions,
-        Dictionary<EntityUid, EntityState> entStates, HashSet<EntityUid> detached)
+    private void UpdateDeletions(NetListAsArray<NetEntity> entityDeletions,
+        Dictionary<NetEntity, EntityState> entStates, HashSet<NetEntity> detached)
     {
         foreach (var ent in entityDeletions.Span)
         {
@@ -311,16 +311,16 @@ public sealed partial class ReplayLoadManager
         }
     }
 
-    private void UpdateEntityStates(ReadOnlySpan<EntityState> span, Dictionary<EntityUid, EntityState> entStates,
-        ref int spawnedTracker, ref int stateTracker, HashSet<EntityUid> detached)
+    private void UpdateEntityStates(ReadOnlySpan<EntityState> span, Dictionary<NetEntity, EntityState> entStates,
+        ref int spawnedTracker, ref int stateTracker, HashSet<NetEntity> detached)
     {
         foreach (var entState in span)
         {
-            detached.Remove(entState.Uid);
-            if (!entStates.TryGetValue(entState.Uid, out var oldEntState))
+            detached.Remove(entState.NetEntity);
+            if (!entStates.TryGetValue(entState.NetEntity, out var oldEntState))
             {
                 var modifiedState = AddImplicitData(entState);
-                entStates[entState.Uid] = modifiedState;
+                entStates[entState.NetEntity] = modifiedState;
                 spawnedTracker++;
 
 #if DEBUG
@@ -333,11 +333,11 @@ public sealed partial class ReplayLoadManager
             }
 
             stateTracker++;
-            DebugTools.Assert(oldEntState.Uid == entState.Uid);
-            entStates[entState.Uid] = MergeStates(entState, oldEntState.ComponentChanges.Value, oldEntState.NetComponents);
+            DebugTools.Assert(oldEntState.NetEntity == entState.NetEntity);
+            entStates[entState.NetEntity] = MergeStates(entState, oldEntState.ComponentChanges.Value, oldEntState.NetComponents);
 
 #if DEBUG
-            foreach (var state in entStates[entState.Uid].ComponentChanges.Span)
+            foreach (var state in entStates[entState.NetEntity].ComponentChanges.Span)
             {
                 DebugTools.Assert(state.State is not IComponentDeltaState delta || delta.FullState);
             }
@@ -388,7 +388,7 @@ public sealed partial class ReplayLoadManager
         }
 
         DebugTools.Assert(newState.NetComponents == null || newState.NetComponents.Count == combined.Count);
-        return new EntityState(newState.Uid, combined, newState.EntityLastModified, newState.NetComponents ?? oldNetComps);
+        return new EntityState(newState.NetEntity, combined, newState.EntityLastModified, newState.NetComponents ?? oldNetComps);
     }
 
     private void UpdatePlayerStates(ReadOnlySpan<PlayerState> span, Dictionary<NetUserId, PlayerState> playerStates)

Robust.Client/Replays/Loading/ReplayLoadManager.Implicit.cs

@@ -70,14 +70,14 @@ public sealed partial class ReplayLoadManager
         {
             // This shouldn't be possible, yet it has happened?
             // TODO this should probably also throw an exception.
-            _sawmill.Error($"Encountered blank entity state? Entity: {entState.Uid}. Last modified: {entState.EntityLastModified}. Attempting to continue.");
+            _sawmill.Error($"Encountered blank entity state? Entity: {entState.NetEntity}. Last modified: {entState.EntityLastModified}. Attempting to continue.");
             return null;
         }
 
         if (!_confMan.GetCVar(CVars.ReplayIgnoreErrors))
-            throw new MissingMetadataException(entState.Uid);
+            throw new MissingMetadataException(entState.NetEntity);
 
-        _sawmill.Error($"Missing metadata component. Entity: {entState.Uid}. Last modified: {entState.EntityLastModified}.");
+        _sawmill.Error($"Missing metadata component. Entity: {entState.NetEntity}. Last modified: {entState.EntityLastModified}.");
         return null;
     }
 }

Robust.Client/Replays/Loading/ReplayLoadManager.Start.cs

@@ -68,10 +68,18 @@ public sealed partial class ReplayLoadManager
             var metaState = (MetaDataComponentState?)ent.ComponentChanges.Value?
                 .FirstOrDefault(c => c.NetID == _metaId).State;
             if (metaState == null)
-                throw new MissingMetadataException(ent.Uid);
+                throw new MissingMetadataException(ent.NetEntity);
 
-            _entMan.CreateEntityUninitialized(metaState.PrototypeId, ent.Uid);
-            entities.Add(ent.Uid);
+            var uid = _entMan.CreateEntityUninitialized(metaState.PrototypeId);
+            entities.Add(uid);
+            var metaComp = _entMan.GetComponent<MetaDataComponent>(uid);
+
+            // Client creates a client-side net entity for the newly created entity.
+            // We need to clear this mapping before assigning the real net id.
+            // TODO NetEntity Jank: prevent the client from creating this in the first place.
+            _entMan.ClearNetEntity(metaComp.NetEntity);
+
+            _entMan.SetNetEntity(uid, ent.NetEntity, metaComp);
 
             if (i++ % 50 == 0)
             {

Robust.Client/Replays/Loading/ReplayLoadManager.cs

@@ -19,7 +19,7 @@ public sealed partial class ReplayLoadManager : IReplayLoadManager
 {
     [Dependency] private readonly ILogManager _logMan = default!;
     [Dependency] private readonly IBaseClient _client = default!;
-    [Dependency] private readonly IEntityManager _entMan = default!;
+    [Dependency] private readonly EntityManager _entMan = default!;
     [Dependency] private readonly IClientGameTiming _timing = default!;
     [Dependency] private readonly IClientNetManager _netMan = default!;
     [Dependency] private readonly IComponentFactory _factory = default!;

Robust.Client/Replays/Playback/ReplayPlaybackManager.Checkpoint.cs

@@ -82,19 +82,28 @@ internal sealed partial class ReplayPlaybackManager
         var metas = _entMan.GetEntityQuery<MetaDataComponent>();
         foreach (var es in checkpoint.DetachedStates)
         {
-            if (metas.TryGetComponent(es.Uid, out var meta) && !meta.EntityDeleted)
+            var uid = _entMan.GetEntity(es.NetEntity);
+            if (metas.TryGetComponent(uid, out var meta) && !meta.EntityDeleted)
                 continue;
-            ;
+
             var metaState = (MetaDataComponentState?)es.ComponentChanges.Value?
                 .FirstOrDefault(c => c.NetID == _metaId).State;
 
             if (metaState == null)
-                throw new MissingMetadataException(es.Uid);
+                throw new MissingMetadataException(es.NetEntity);
 
-            _entMan.CreateEntityUninitialized(metaState.PrototypeId, es.Uid);
-            meta = metas.GetComponent(es.Uid);
-            _entMan.InitializeEntity(es.Uid, meta);
-            _entMan.StartEntity(es.Uid);
+            _entMan.CreateEntityUninitialized(metaState.PrototypeId, uid);
+            meta = metas.GetComponent(uid);
+
+            // Client creates a client-side net entity for the newly created entity.
+            // We need to clear this mapping before assigning the real net id.
+            // TODO NetEntity Jank: prevent the client from creating this in the first place.
+            _entMan.ClearNetEntity(meta.NetEntity);
+
+            _entMan.SetNetEntity(uid, es.NetEntity, meta);
+
+            _entMan.InitializeEntity(uid, meta);
+            _entMan.StartEntity(uid);
             meta.LastStateApplied = checkpoint.Tick;
         }
     }

Robust.Client/Replays/Playback/ReplayPlaybackManager.Update.cs

@@ -50,7 +50,7 @@ internal sealed partial class ReplayPlaybackManager
         }
 
         _timing.CurTick += 1;
-        _entMan.TickUpdate(args.DeltaSeconds, noPredictions: true);
+        _cEntManager.TickUpdate(args.DeltaSeconds, noPredictions: true);
 
         if (!Playing || AutoPauseCountdown == null)
             return;
@@ -82,7 +82,7 @@ internal sealed partial class ReplayPlaybackManager
                 // Maybe track our own detach queue and use _gameState.DetachImmediate()?
                 // That way we don't have to clone this. Downside would be that all entities will be immediately
                 // detached. I.e., the detach budget cvar will simply be ignored.
-                var clone = new List<EntityUid>(leavePvs.Entities);
+                var clone = new List<NetEntity>(leavePvs.Entities);
 
                 _gameState.QueuePvsDetach(clone, leavePvs.Tick);
                 continue;

Robust.Client/Replays/Playback/ReplayPlaybackManager.cs

@@ -33,7 +33,8 @@ internal sealed partial class ReplayPlaybackManager : IReplayPlaybackManager
     [Dependency] private readonly IComponentFactory _factory = default!;
     [Dependency] private readonly IPrototypeManager _protoMan = default!;
     [Dependency] private readonly IGameController _controller = default!;
-    [Dependency] private readonly IClientEntityManager _entMan = default!;
+    [Dependency] private readonly IClientEntityManager _cEntManager = default!;
+    [Dependency] private readonly ClientEntityManager _entMan = default!;
     [Dependency] private readonly IConfigurationManager _confMan = default!;
     [Dependency] private readonly NetworkResourceManager _netResMan = default!;
     [Dependency] private readonly IClientGameStateManager _gameState = default!;

Robust.Client/Replays/ReplayRecordingManager.cs

@@ -95,12 +95,12 @@ internal sealed class ReplayRecordingManager : SharedReplayRecordingManager
     {
         var tick = _timing.LastRealTick;
         var players = _player.Sessions.Select(GetPlayerState).ToArray();
-        var deletions = Array.Empty<EntityUid>();
+        var deletions = Array.Empty<NetEntity>();
 
         var fullRep = _state.GetFullRep();
         var entStates = new EntityState[fullRep.Count];
         var i = 0;
-        foreach (var (uid, dict) in fullRep)
+        foreach (var (netEntity, dict) in fullRep)
         {
             var compData = new ComponentChange[dict.Count];
             var netComps = new HashSet<ushort>(dict.Keys);
@@ -110,7 +110,7 @@ internal sealed class ReplayRecordingManager : SharedReplayRecordingManager
                 compData[j++] = new ComponentChange(id, compState, tick);
             }
 
-            entStates[i++] = new EntityState(uid, compData, tick, netComps);
+            entStates[i++] = new EntityState(netEntity, compData, tick, netComps);
         }
 
         var state = new GameState(
@@ -121,16 +121,17 @@ internal sealed class ReplayRecordingManager : SharedReplayRecordingManager
             players,
             deletions);
 
-        var detached = new List<EntityUid>();
+        var detached = new List<NetEntity>();
         var query = _entMan.AllEntityQueryEnumerator<MetaDataComponent>();
         while (query.MoveNext(out var uid, out var comp))
         {
-            if (uid.IsClientSide())
+            if (_entMan.IsClientSide(uid))
                 continue;
 
-            DebugTools.Assert(fullRep.ContainsKey(uid));
+            var nent = comp.NetEntity;
+            DebugTools.Assert(fullRep.ContainsKey(nent));
             if ((comp.Flags & MetaDataFlags.Detached) != 0)
-                detached.Add(uid);
+                detached.Add(nent);
         }
 
         var detachMsg = detached.Count > 0 ? new ReplayMessage.LeavePvs(detached, tick) : null;
@@ -144,7 +145,7 @@ internal sealed class ReplayRecordingManager : SharedReplayRecordingManager
             UserId = session.UserId,
             Status = session.Status,
             Name = session.Name,
-            ControlledEntity = session.AttachedEntity,
+            ControlledEntity = _entMan.GetNetEntity(session.AttachedEntity),
         };
     }
 }

Robust.Client/ViewVariables/ClientViewVariablesManager.cs

@@ -218,7 +218,7 @@ namespace Robust.Client.ViewVariables
         {
             // TODO: more flexibility in allowing custom instances here.
             ViewVariablesInstance instance;
-            if (obj is EntityUid entity && _entityManager.EntityExists(entity))
+            if (obj is NetEntity netEntity && _entityManager.GetEntity(netEntity).IsValid())
             {
                 instance = new ViewVariablesInstanceEntity(this, _entityManager, _robustSerializer, Sawmill);
             }
@@ -269,7 +269,7 @@ namespace Robust.Client.ViewVariables
             var type = Type.GetType(blob.ObjectType);
             // TODO: more flexibility in allowing custom instances here.
             ViewVariablesInstance instance;
-            if (type != null && typeof(EntityUid).IsAssignableFrom(type))
+            if (type != null && typeof(NetEntity).IsAssignableFrom(type))
             {
                 instance = new ViewVariablesInstanceEntity(this, _entityManager, _robustSerializer, Sawmill);
             }

Robust.Client/ViewVariables/Instances/ViewVariablesInstanceEntity.cs

@@ -41,7 +41,8 @@ namespace Robust.Client.ViewVariables.Instances
         private const int TabServerComponents = 3;
 
         private TabContainer _tabs = default!;
-        private EntityUid _entity = default!;
+        private EntityUid _entity;
+        private NetEntity _netEntity = default!;
 
         private ViewVariablesAddWindow? _addComponentWindow;
         private bool _addComponentServer;
@@ -71,7 +72,8 @@ namespace Robust.Client.ViewVariables.Instances
 
         public override void Initialize(DefaultWindow window, object obj)
         {
-            _entity = (EntityUid) obj;
+            _netEntity = (NetEntity) obj;
+            _entity = _entityManager.GetEntity(_netEntity);
 
             var scrollContainer = new ScrollContainer();
             //scrollContainer.SetAnchorPreset(Control.LayoutPreset.Wide, true);
@@ -163,7 +165,7 @@ namespace Robust.Client.ViewVariables.Instances
 
             PopulateClientComponents();
 
-            if (!_entity.IsClientSide())
+            if (!_entityManager.IsClientSide(_entity))
             {
                 _serverVariables = new BoxContainer
                 {
@@ -268,12 +270,12 @@ namespace Robust.Client.ViewVariables.Instances
                 button.OnPressed += _ =>
                 {
                     ViewVariablesManager.OpenVV(
-                        new ViewVariablesComponentSelector(_entity, componentType.FullName));
+                        new ViewVariablesComponentSelector(_entityManager.GetNetEntity(_entity), componentType.FullName));
                 };
                 removeButton.OnPressed += _ =>
                 {
                     // We send a command to remove the component.
-                    IoCManager.Resolve<IClientConsoleHost>().RemoteExecuteCommand(null, $"rmcomp {_entity} {componentType.ComponentName}");
+                    IoCManager.Resolve<IClientConsoleHost>().RemoteExecuteCommand(null, $"rmcomp {_netEntity} {componentType.ComponentName}");
                     PopulateServerComponents();
                 };
                 button.AddChild(removeButton);
@@ -417,7 +419,7 @@ namespace Robust.Client.ViewVariables.Instances
             if (_addComponentServer)
             {
                 // Attempted to add a component to the server entity... We send a command.
-                IoCManager.Resolve<IClientConsoleHost>().RemoteExecuteCommand(null, $"addcomp {_entity} {eventArgs.Entry}");
+                IoCManager.Resolve<IClientConsoleHost>().RemoteExecuteCommand(null, $"addcomp {_netEntity} {eventArgs.Entry}");
                 PopulateServerComponents();
                 _addComponentWindow?.Populate(await GetValidServerComponentsForAdding());
                 return;
@@ -504,7 +506,7 @@ namespace Robust.Client.ViewVariables.Instances
                 try
                 {
                     _entitySession =
-                        await ViewVariablesManager.RequestSession(new ViewVariablesEntitySelector(_entity));
+                        await ViewVariablesManager.RequestSession(new ViewVariablesEntitySelector(_netEntity));
                 }
                 catch (SessionDenyException e)
                 {

Robust.Client/ViewVariables/ViewVariablesCommand.cs

@@ -63,20 +63,22 @@ namespace Robust.Client.ViewVariables
             }
 
             // Entity.
-            if (!EntityUid.TryParse(args[0], out var entity))
+            if (!NetEntity.TryParse(args[0], out var netEntity))
             {
                 shell.WriteLine("Invalid specifier format.");
                 return;
             }
 
+            var entity = _entities.GetEntity(netEntity);
+
             if (!_entities.EntityExists(entity))
             {
                 shell.WriteLine("That entity does not exist locally. Attempting to open remote view...");
-                _cvvm.OpenVV(new ViewVariablesEntitySelector(entity));
+                _cvvm.OpenVV(new ViewVariablesEntitySelector(netEntity));
                 return;
             }
 
-            _cvvm.OpenVV(entity);
+            _cvvm.OpenVV(netEntity);
         }
     }
 }

Robust.Server/Console/Commands/AddComponentCommand.cs

@@ -22,13 +22,13 @@ namespace Robust.Server.Console.Commands
                 return;
             }
 
-            if (!EntityUid.TryParse(args[0], out var uid))
+            if (!NetEntity.TryParse(args[0], out var uidNet))
             {
-                shell.WriteLine($"{uid} is not a valid entity uid.");
+                shell.WriteLine($"{args[0]} is not a valid entity.");
                 return;
             }
 
-            if (!_entityManager.EntityExists(uid))
+            if (!_entityManager.TryGetEntity(uidNet, out var uid) || !_entityManager.EntityExists(uid))
             {
                 shell.WriteLine($"No entity found with id {uid}.");
                 return;
@@ -44,17 +44,17 @@ namespace Robust.Server.Console.Commands
 
             if (_entityManager.HasComponent(uid, registration.Type))
             {
-                shell.WriteLine($"Entity {_entityManager.GetComponent<MetaDataComponent>(uid).EntityName} already has a {componentName} component.");
+                shell.WriteLine($"Entity {_entityManager.GetComponent<MetaDataComponent>(uid.Value).EntityName} already has a {componentName} component.");
             }
 
             var component = (Component) _componentFactory.GetComponent(registration.Type);
 
 #pragma warning disable CS0618
-            component.Owner = uid;
+            component.Owner = uid.Value;
 #pragma warning restore CS0618
-            _entityManager.AddComponent(uid, component);
+            _entityManager.AddComponent(uid.Value, component);
 
-            shell.WriteLine($"Added {componentName} component to entity {_entityManager.GetComponent<MetaDataComponent>(uid).EntityName}.");
+            shell.WriteLine($"Added {componentName} component to entity {_entityManager.GetComponent<MetaDataComponent>(uid.Value).EntityName}.");
         }
     }
 }

Robust.Server/Console/Commands/DeleteCommand.cs

@@ -19,19 +19,19 @@ namespace Robust.Server.Console.Commands
                 return;
             }
 
-            if (!EntityUid.TryParse(args[0], out var entity))
+            if (!NetEntity.TryParse(args[0], out var entityNet))
             {
                 shell.WriteLine("Invalid entity UID.");
                 return;
             }
 
-            if (!_entityManager.EntityExists(entity))
+            if (!_entityManager.TryGetEntity(entityNet, out var entity) || !_entityManager.EntityExists(entity))
             {
                 shell.WriteLine("That entity does not exist.");
                 return;
             }
 
-            _entityManager.DeleteEntity(entity);
+            _entityManager.DeleteEntity(entity.Value);
         }
     }
 }

Robust.Server/Console/Commands/MapCommands.cs

@@ -27,12 +27,14 @@ namespace Robust.Server.Console.Commands
                 return;
             }
 
-            if (!EntityUid.TryParse(args[0], out var uid))
+            if (!NetEntity.TryParse(args[0], out var uidNet))
             {
                 shell.WriteError("Not a valid entity ID.");
                 return;
             }
 
+            var uid = _ent.GetEntity(uidNet);
+
             // no saving default grid
             if (!_ent.EntityExists(uid))
             {

Robust.Server/Console/Commands/RemoveComponentCommand.cs

@@ -22,12 +22,14 @@ namespace Robust.Server.Console.Commands
                 return;
             }
 
-            if (!EntityUid.TryParse(args[0], out var uid))
+            if (!NetEntity.TryParse(args[0], out var netEntity))
             {
-                shell.WriteLine($"{uid} is not a valid entity uid.");
+                shell.WriteLine($"{netEntity} is not a valid entity uid.");
                 return;
             }
 
+            var uid = _entityManager.GetEntity(netEntity);
+
             if (!_entityManager.EntityExists(uid))
             {
                 shell.WriteLine($"No entity found with id {uid}.");

Robust.Server/Console/Commands/ScaleCommand.cs

@@ -24,7 +24,7 @@ public sealed class ScaleCommand : LocalizedCommands
             return;
         }
 
-        if (!EntityUid.TryParse(args[0], out var uid))
+        if (!NetEntity.TryParse(args[0], out var netEntity))
         {
             shell.WriteError($"Unable to find entity {args[0]}");
             return;
@@ -47,6 +47,7 @@ public sealed class ScaleCommand : LocalizedCommands
         var physics = _entityManager.System<SharedPhysicsSystem>();
         var appearance = _entityManager.System<AppearanceSystem>();
 
+        var uid = _entityManager.GetEntity(netEntity);
         _entityManager.EnsureComponent<ScaleVisualsComponent>(uid);
         var @event = new ScaleEntityEvent();
         _entityManager.EventBus.RaiseLocalEvent(uid, ref @event);

Robust.Server/Console/Commands/SpinCommand.cs

@@ -29,10 +29,12 @@ public sealed class SpinCommand : LocalizedCommands
         }
 
         // get the target
-        EntityUid target;
+        EntityUid? target;
+
         if (args.Length == 3)
         {
-            if (!EntityUid.TryParse(args[2], out target))
+            if (!NetEntity.TryParse(args[2], out var targetNet) ||
+                !_entities.TryGetEntity(targetNet, out target))
             {
                 shell.WriteError($"Unable to find entity {args[1]}");
                 return;
@@ -65,6 +67,6 @@ public sealed class SpinCommand : LocalizedCommands
 
         var physicsSystem = _entities.System<SharedPhysicsSystem>();
         physicsSystem.SetAngularDamping(physics, drag);
-        physicsSystem.SetAngularVelocity(target, speed, body: physics);
+        physicsSystem.SetAngularVelocity(target.Value, speed, body: physics);
     }
 }

Robust.Server/Console/Commands/ViewSubscriberCommand.cs

@@ -29,19 +29,19 @@ namespace Robust.Server.Console.Commands
                 return;
             }
 
-            if (!EntityUid.TryParse(args[0], out var uid))
+            if (!NetEntity.TryParse(args[0], out var uidNet))
             {
                 shell.WriteError($"Unable to parse {args[0]} as a {nameof(EntityUid)}");
                 return;
             }
 
-            if (!_entities.EntityExists(uid))
+            if (!_entities.TryGetEntity(uidNet, out var uid) || !_entities.EntityExists(uid))
             {
                 shell.WriteError($"Unable to find entity {uid}");
                 return;
             }
 
-            _entities.EntitySysManager.GetEntitySystem<ViewSubscriberSystem>().AddViewSubscriber(uid, playerSession);
+            _entities.EntitySysManager.GetEntitySystem<ViewSubscriberSystem>().AddViewSubscriber(uid.Value, playerSession);
         }
 
         public sealed class RemoveViewSubscriberCommand : LocalizedCommands
@@ -66,19 +66,19 @@ namespace Robust.Server.Console.Commands
                     return;
                 }
 
-                if (!EntityUid.TryParse(args[0], out var uid))
+                if (!NetEntity.TryParse(args[0], out var uidNet))
                 {
-                    shell.WriteError($"Unable to parse {args[0]} as a {nameof(EntityUid)}");
+                    shell.WriteError($"Unable to parse {args[0]} as a {nameof(NetEntity)}");
                     return;
                 }
 
-                if (!_entities.EntityExists(uid))
+                if (!_entities.TryGetEntity(uidNet, out var uid) || !_entities.EntityExists(uid))
                 {
                     shell.WriteError($"Unable to find entity {uid}");
                     return;
                 }
 
-                _entities.EntitySysManager.GetEntitySystem<ViewSubscriberSystem>().RemoveViewSubscriber(uid, playerSession);
+                _entities.EntitySysManager.GetEntitySystem<ViewSubscriberSystem>().RemoveViewSubscriber(uid.Value, playerSession);
             }
         }
     }

Robust.Server/Containers/ContainerSystem.cs

@@ -6,7 +6,7 @@ namespace Robust.Server.Containers
 {
     public sealed class ContainerSystem : SharedContainerSystem
     {
-        protected override void ValidateMissingEntity(EntityUid uid, IContainer cont, EntityUid missing)
+        protected override void ValidateMissingEntity(EntityUid uid, BaseContainer cont, EntityUid missing)
         {
             Log.Error($"Missing entity for container {ToPrettyString(uid)}. Missing uid: {missing}");
             //cont.InternalRemove(ent);

Robust.Server/GameObjects/EntitySystems/AudioSystem.cs

@@ -86,9 +86,9 @@ public sealed class AudioSystem : SharedAudioSystem
         var msg = new PlayAudioEntityMessage
         {
             FileName = filename,
-            Coordinates = transform.Coordinates,
-            FallbackCoordinates = fallbackCoordinates,
-            EntityUid = uid,
+            Coordinates = GetNetCoordinates(transform.Coordinates),
+            FallbackCoordinates = GetNetCoordinates(fallbackCoordinates),
+            NetEntity = GetNetEntity(uid),
             AudioParams = audioParams ?? AudioParams.Default,
             Identifier = id,
         };
@@ -108,8 +108,8 @@ public sealed class AudioSystem : SharedAudioSystem
         var msg = new PlayAudioPositionalMessage
         {
             FileName = filename,
-            Coordinates = coordinates,
-            FallbackCoordinates = fallbackCoordinates,
+            Coordinates = GetNetCoordinates(coordinates),
+            FallbackCoordinates = GetNetCoordinates(fallbackCoordinates),
             AudioParams = audioParams ?? AudioParams.Default,
             Identifier = id
         };

Robust.Server/GameObjects/EntitySystems/InputSystem.cs

@@ -61,7 +61,7 @@ namespace Robust.Server.GameObjects
             //Client Sanitization: unbound command, just ignore
             foreach (var handler in BindRegistry.GetHandlers(function))
             {
-                if (handler.HandleCmdMessage(session, msg)) return;
+                if (handler.HandleCmdMessage(EntityManager, session, msg)) return;
             }
         }
 

Robust.Server/GameObjects/EntitySystems/UserInterfaceSystem.cs

@@ -83,7 +83,7 @@ namespace Robust.Server.GameObjects
         /// </summary>
         private void OnMessageReceived(BoundUIWrapMessage msg, EntitySessionEventArgs args)
         {
-            var uid = msg.Entity;
+            var uid = GetEntity(msg.Entity);
             if (!TryComp(uid, out ServerUserInterfaceComponent? uiComp) || args.SenderSession is not IPlayerSession session)
                 return;
 
@@ -118,7 +118,7 @@ namespace Robust.Server.GameObjects
             // get the wrapped message and populate it with the sender & UI key information.
             var message = msg.Message;
             message.Session = args.SenderSession;
-            message.Entity = uid;
+            message.Entity = GetNetEntity(uid);
             message.UiKey = msg.UiKey;
 
             // Raise as object so the correct type is used.
@@ -321,9 +321,9 @@ namespace Robust.Server.GameObjects
         ///     The player session to send this new state to.
         ///     Set to null for sending it to every subscribed player session.
         /// </param>
-        public static void SetUiState(BoundUserInterface bui, BoundUserInterfaceState state, IPlayerSession? session = null, bool clearOverrides = true)
+        public void SetUiState(BoundUserInterface bui, BoundUserInterfaceState state, IPlayerSession? session = null, bool clearOverrides = true)
         {
-            var msg = new BoundUIWrapMessage(bui.Owner, new UpdateBoundStateMessage(state), bui.UiKey);
+            var msg = new BoundUIWrapMessage(GetNetEntity(bui.Owner), new UpdateBoundStateMessage(state), bui.UiKey);
             if (session == null)
             {
                 bui.LastStateMsg = msg;
@@ -385,7 +385,7 @@ namespace Robust.Server.GameObjects
             _openInterfaces.GetOrNew(session).Add(bui);
             RaiseLocalEvent(bui.Owner, new BoundUIOpenedEvent(bui.UiKey, bui.Owner, session));
 
-            RaiseNetworkEvent(new BoundUIWrapMessage(bui.Owner, new OpenBoundInterfaceMessage(), bui.UiKey), session.ConnectedClient);
+            RaiseNetworkEvent(new BoundUIWrapMessage(GetNetEntity(bui.Owner), new OpenBoundInterfaceMessage(), bui.UiKey), session.ConnectedClient);
 
             // Fun fact, clients needs to have BUIs open before they can receive the state.....
             if (bui.LastStateMsg != null)
@@ -414,7 +414,7 @@ namespace Robust.Server.GameObjects
             if (!bui._subscribedSessions.Remove(session))
                 return false;
 
-            RaiseNetworkEvent(new BoundUIWrapMessage(bui.Owner, new CloseBoundInterfaceMessage(), bui.UiKey), session.ConnectedClient);
+            RaiseNetworkEvent(new BoundUIWrapMessage(GetNetEntity(bui.Owner), new CloseBoundInterfaceMessage(), bui.UiKey), session.ConnectedClient);
             CloseShared(bui, session, activeUis);
             return true;
         }
@@ -492,7 +492,7 @@ namespace Robust.Server.GameObjects
         /// </summary>
         public void SendUiMessage(BoundUserInterface bui, BoundUserInterfaceMessage message)
         {
-            var msg = new BoundUIWrapMessage(bui.Owner, message, bui.UiKey);
+            var msg = new BoundUIWrapMessage(GetNetEntity(bui.Owner), message, bui.UiKey);
             foreach (var session in bui.SubscribedSessions)
             {
                 RaiseNetworkEvent(msg, session.ConnectedClient);
@@ -518,7 +518,7 @@ namespace Robust.Server.GameObjects
             if (!bui.SubscribedSessions.Contains(session))
                 return false;
 
-            RaiseNetworkEvent(new BoundUIWrapMessage(bui.Owner, message, bui.UiKey), session.ConnectedClient);
+            RaiseNetworkEvent(new BoundUIWrapMessage(GetNetEntity(bui.Owner), message, bui.UiKey), session.ConnectedClient);
             return true;
         }
 

Robust.Server/GameObjects/IServerEntityManagerInternal.cs

@@ -8,7 +8,7 @@ namespace Robust.Server.GameObjects
         // These methods are used by the map loader to do multi-stage entity construction during map load.
         // I would recommend you refer to the MapLoader for usage.
 
-        EntityUid AllocEntity(EntityPrototype? prototype, EntityUid uid = default);
+        EntityUid AllocEntity(EntityPrototype? prototype);
 
         void FinishEntityLoad(EntityUid entity, IEntityLoadContext? context = null);
 

Robust.Server/GameObjects/ServerEntityManager.cs

@@ -42,8 +42,6 @@ namespace Robust.Server.GameObjects
 
         private ISawmill _netEntSawmill = default!;
 
-        protected override int NextEntityUid { get; set; } = (int) EntityUid.FirstUid;
-
         public override void Initialize()
         {
             _netEntSawmill = LogManager.GetSawmill("net.ent");
@@ -54,9 +52,9 @@ namespace Robust.Server.GameObjects
             base.Initialize();
         }
 
-        EntityUid IServerEntityManagerInternal.AllocEntity(EntityPrototype? prototype, EntityUid uid)
+        EntityUid IServerEntityManagerInternal.AllocEntity(EntityPrototype? prototype)
         {
-            return AllocEntity(prototype, out _, uid);
+            return AllocEntity(prototype, out _);
         }
 
         void IServerEntityManagerInternal.FinishEntityLoad(EntityUid entity, IEntityLoadContext? context)
@@ -79,15 +77,15 @@ namespace Robust.Server.GameObjects
             StartEntity(entity);
         }
 
-        private protected override EntityUid CreateEntity(string? prototypeName, EntityUid uid = default, IEntityLoadContext? context = null)
+        private protected override EntityUid CreateEntity(string? prototypeName, IEntityLoadContext? context = null)
         {
             if (prototypeName == null)
-                return base.CreateEntity(prototypeName, uid, context);
+                return base.CreateEntity(prototypeName, context);
 
             if (!PrototypeManager.TryIndex<EntityPrototype>(prototypeName, out var prototype))
                 throw new EntityCreationException($"Attempted to spawn an entity with an invalid prototype: {prototypeName}");
 
-            var entity = base.CreateEntity(prototype, uid, context);
+            var entity = base.CreateEntity(prototype, context);
 
             // At this point in time, all data configure on the entity *should* be purely from the prototype.
             // As such, we can reset the modified ticks to Zero,

Robust.Server/GameStates/IServerGameStateManager.cs

@@ -24,6 +24,6 @@ namespace Robust.Server.GameStates
 
         Action<ICommonSession, GameTick>? ClientAck { get; set; }
 
-        Action<ICommonSession, GameTick, EntityUid?>? ClientRequestFull { get; set; }
+        Action<ICommonSession, GameTick, NetEntity?>? ClientRequestFull { get; set; }
     }
 }

Robust.Server/GameStates/PvsOverrideSystem.cs

@@ -18,7 +18,7 @@ public sealed class PvsOverrideSystem : EntitySystem
     /// <param name="recursive">If true, this will also recursively send any children of the given index.</param>
     public void AddGlobalOverride(EntityUid uid, bool removeExistingOverride = true, bool recursive = false)
     {
-        _pvs.EntityPVSCollection.AddGlobalOverride(uid, removeExistingOverride, recursive);
+        _pvs.EntityPVSCollection.AddGlobalOverride(GetNetEntity(uid), removeExistingOverride, recursive);
     }
 
     /// <summary>
@@ -28,7 +28,7 @@ public sealed class PvsOverrideSystem : EntitySystem
     /// <param name="removeExistingOverride">Whether or not to supersede existing overrides.</param>
     public void AddSessionOverride(EntityUid uid, ICommonSession session,bool removeExistingOverride = true)
     {
-        _pvs.EntityPVSCollection.UpdateIndex(uid, session, removeExistingOverride);
+        _pvs.EntityPVSCollection.UpdateIndex(GetNetEntity(uid), session, removeExistingOverride);
     }
 
     /// <summary>
@@ -39,6 +39,6 @@ public sealed class PvsOverrideSystem : EntitySystem
         if (!Resolve(uid, ref xform))
             return;
 
-        _pvs.EntityPVSCollection.UpdateIndex(uid, xform.Coordinates, true);
+        _pvs.EntityPVSCollection.UpdateIndex(GetNetEntity(uid), xform.Coordinates, true);
     }
 }

Robust.Server/GameStates/PvsSystem.Ack.cs

@@ -45,7 +45,7 @@ internal sealed partial class PvsSystem
             return;
 
         var ackedTick = sessionData.LastReceivedAck;
-        Dictionary<EntityUid, PvsEntityVisibility>? ackedData;
+        Dictionary<NetEntity, PvsEntityVisibility>? ackedData;
 
         if (sessionData.Overflow != null && sessionData.Overflow.Value.Tick <= ackedTick)
         {

Robust.Server/GameStates/PvsSystem.cs

@@ -24,14 +24,13 @@ namespace Robust.Server.GameStates;
 
 internal sealed partial class PvsSystem : EntitySystem
 {
+    [Shared.IoC.Dependency] private readonly IConfigurationManager _configManager = default!;
     [Shared.IoC.Dependency] private readonly IMapManagerInternal _mapManager = default!;
     [Shared.IoC.Dependency] private readonly IPlayerManager _playerManager = default!;
-    [Shared.IoC.Dependency] private readonly IConfigurationManager _configManager = default!;
-    [Shared.IoC.Dependency] private readonly SharedTransformSystem _transform = default!;
-    [Shared.IoC.Dependency] private readonly IServerNetConfigurationManager _netConfigManager = default!;
-    [Shared.IoC.Dependency] private readonly IServerGameStateManager _serverGameStateManager = default!;
     [Shared.IoC.Dependency] private readonly IParallelManager _parallelManager = default!;
-    [Shared.IoC.Dependency] private readonly IComponentFactory _factory = default!;
+    [Shared.IoC.Dependency] private readonly IServerGameStateManager _serverGameStateManager = default!;
+    [Shared.IoC.Dependency] private readonly IServerNetConfigurationManager _netConfigManager = default!;
+    [Shared.IoC.Dependency] private readonly SharedTransformSystem _transform = default!;
 
     public const float ChunkSize = 8;
 
@@ -63,31 +62,28 @@ internal sealed partial class PvsSystem : EntitySystem
 
     internal readonly Dictionary<ICommonSession, SessionPVSData> PlayerData = new();
 
-    private PVSCollection<EntityUid> _entityPvsCollection = default!;
-    public PVSCollection<EntityUid> EntityPVSCollection => _entityPvsCollection;
+    private PVSCollection<NetEntity> _entityPvsCollection = default!;
+    public PVSCollection<NetEntity> EntityPVSCollection => _entityPvsCollection;
 
     private readonly List<IPVSCollection> _pvsCollections = new();
 
-    private readonly ObjectPool<Dictionary<EntityUid, PvsEntityVisibility>> _visSetPool
-        = new DefaultObjectPool<Dictionary<EntityUid, PvsEntityVisibility>>(
-            new DictPolicy<EntityUid, PvsEntityVisibility>(), MaxVisPoolSize);
+    private readonly ObjectPool<Dictionary<NetEntity, PvsEntityVisibility>> _visSetPool
+        = new DefaultObjectPool<Dictionary<NetEntity, PvsEntityVisibility>>(
+            new DictPolicy<NetEntity, PvsEntityVisibility>(), MaxVisPoolSize);
 
-    private readonly ObjectPool<Stack<EntityUid>> _stackPool
-        = new DefaultObjectPool<Stack<EntityUid>>(
-            new StackPolicy<EntityUid>(), MaxVisPoolSize);
+    private readonly ObjectPool<Stack<NetEntity>> _stackPool
+        = new DefaultObjectPool<Stack<NetEntity>>(
+            new StackPolicy<NetEntity>(), MaxVisPoolSize);
 
-    private readonly ObjectPool<HashSet<EntityUid>> _uidSetPool
-        = new DefaultObjectPool<HashSet<EntityUid>>(new SetPolicy<EntityUid>(), MaxVisPoolSize);
-
-    private readonly ObjectPool<Dictionary<EntityUid, MetaDataComponent>> _chunkCachePool =
-        new DefaultObjectPool<Dictionary<EntityUid, MetaDataComponent>>(
-            new DictPolicy<EntityUid, MetaDataComponent>(), MaxVisPoolSize);
+    private readonly ObjectPool<Dictionary<NetEntity, MetaDataComponent>> _chunkCachePool =
+        new DefaultObjectPool<Dictionary<NetEntity, MetaDataComponent>>(
+            new DictPolicy<NetEntity, MetaDataComponent>(), MaxVisPoolSize);
 
     private readonly ObjectPool<HashSet<int>> _playerChunkPool =
         new DefaultObjectPool<HashSet<int>>(new SetPolicy<int>(), MaxVisPoolSize);
 
-    private readonly ObjectPool<RobustTree<EntityUid>> _treePool =
-        new DefaultObjectPool<RobustTree<EntityUid>>(new TreePolicy<EntityUid>(), MaxVisPoolSize);
+    private readonly ObjectPool<RobustTree<NetEntity>> _treePool =
+        new DefaultObjectPool<RobustTree<NetEntity>>(new TreePolicy<NetEntity>(), MaxVisPoolSize);
 
     private readonly ObjectPool<Dictionary<MapChunkLocation, int>> _mapChunkPool =
         new DefaultObjectPool<Dictionary<MapChunkLocation, int>>(
@@ -102,19 +98,25 @@ internal sealed partial class PvsSystem : EntitySystem
     private readonly List<(uint, IChunkIndexLocation)> _chunkList = new(64);
     internal readonly HashSet<ICommonSession> PendingAcks = new();
 
+    private readonly Dictionary<(uint visMask, IChunkIndexLocation location), (Dictionary<NetEntity, MetaDataComponent> metadata,
+        RobustTree<NetEntity> tree)?> _previousTrees = new();
+
+    private readonly HashSet<(uint visMask, IChunkIndexLocation location)> _reusedTrees = new();
+
     private EntityQuery<EyeComponent> _eyeQuery;
-    private EntityQuery<TransformComponent> _xformQuery;
     private EntityQuery<MetaDataComponent> _metaQuery;
+    private EntityQuery<TransformComponent> _xformQuery;
 
     public override void Initialize()
     {
         base.Initialize();
 
         _eyeQuery = GetEntityQuery<EyeComponent>();
+        _metaQuery = GetEntityQuery<MetaDataComponent>();
         _xformQuery = GetEntityQuery<TransformComponent>();
         _metaQuery = GetEntityQuery<MetaDataComponent>();
 
-        _entityPvsCollection = RegisterPVSCollection<EntityUid>();
+        _entityPvsCollection = RegisterPVSCollection<NetEntity>();
 
         SubscribeLocalEvent<MapChangedEvent>(ev =>
         {
@@ -159,7 +161,7 @@ internal sealed partial class PvsSystem : EntitySystem
     }
 
     // TODO rate limit this?
-    private void OnClientRequestFull(ICommonSession session, GameTick tick, EntityUid? missingEntity)
+    private void OnClientRequestFull(ICommonSession session, GameTick tick, NetEntity? missingEntity)
     {
         if (!PlayerData.TryGetValue(session, out var sessionData))
             return;
@@ -173,7 +175,8 @@ internal sealed partial class PvsSystem : EntitySystem
 
         if (missingEntity != null)
         {
-            sb.Append($" Apparently they received an entity without metadata: {ToPrettyString(missingEntity.Value)}.");
+            var entity = GetEntity(missingEntity)!;
+            sb.Append($" Apparently they received an entity without metadata: {ToPrettyString(entity.Value)}.");
 
             if (sessionData.LastSeenAt.TryGetValue(missingEntity.Value, out var lastSeenTick))
                 sb.Append($" Entity last sent: {lastSeenTick.Value}");
@@ -240,17 +243,17 @@ internal sealed partial class PvsSystem : EntitySystem
 
     #region PVSCollection Event Updates
 
-    private void OnEntityDeleted(EntityUid e)
+    private void OnEntityDeleted(EntityUid e, MetaDataComponent metadata)
     {
-        _entityPvsCollection.RemoveIndex(EntityManager.CurrentTick, e);
+        _entityPvsCollection.RemoveIndex(EntityManager.CurrentTick, metadata.NetEntity);
 
         var previousTick = _gameTiming.CurTick - 1;
 
         foreach (var sessionData in PlayerData.Values)
         {
-            sessionData.LastSeenAt.Remove(e);
+            sessionData.LastSeenAt.Remove(metadata.NetEntity);
             if (sessionData.SentEntities.TryGetValue(previousTick, out var ents))
-                ents.Remove(e);
+                ents.Remove(metadata.NetEntity);
         }
     }
 
@@ -278,7 +281,7 @@ internal sealed partial class PvsSystem : EntitySystem
         DebugTools.Assert(!_mapManager.IsMap(ev.Sender));
 
         var coordinates = _transform.GetMoverCoordinates(ev.Sender, ev.Component);
-        UpdateEntityRecursive(ev.Sender, ev.Component, coordinates, false, ev.ParentChanged);
+        UpdateEntityRecursive(ev.Sender, _metaQuery.GetComponent(ev.Sender), ev.Component, coordinates, false, ev.ParentChanged);
     }
 
     private void OnTransformStartup(EntityUid uid, TransformComponent component, ref TransformStartupEvent args)
@@ -295,10 +298,10 @@ internal sealed partial class PvsSystem : EntitySystem
         DebugTools.Assert(!_mapManager.IsMap(uid));
 
         var coordinates = _transform.GetMoverCoordinates(uid, component);
-        UpdateEntityRecursive(uid, component, coordinates, false, false);
+        UpdateEntityRecursive(uid, _metaQuery.GetComponent(uid), component, coordinates, false, false);
     }
 
-    private void UpdateEntityRecursive(EntityUid uid, TransformComponent xform, EntityCoordinates coordinates, bool mover, bool forceDirty)
+    private void UpdateEntityRecursive(EntityUid uid, MetaDataComponent metadata, TransformComponent xform, EntityCoordinates coordinates, bool mover, bool forceDirty)
     {
         if (mover && !xform.LocalPosition.Equals(Vector2.Zero))
         {
@@ -310,9 +313,9 @@ internal sealed partial class PvsSystem : EntitySystem
 
         var indices = PVSCollection<EntityUid>.GetChunkIndices(coordinates.Position);
         if (xform.GridUid != null)
-            _entityPvsCollection.UpdateIndex(uid, xform.GridUid.Value, indices, forceDirty: forceDirty);
+            _entityPvsCollection.UpdateIndex(metadata.NetEntity, xform.GridUid.Value, indices, forceDirty: forceDirty);
         else
-            _entityPvsCollection.UpdateIndex(uid, xform.MapID, indices, forceDirty: forceDirty);
+            _entityPvsCollection.UpdateIndex(metadata.NetEntity, xform.MapID, indices, forceDirty: forceDirty);
 
         var children = xform.ChildEnumerator;
 
@@ -322,7 +325,7 @@ internal sealed partial class PvsSystem : EntitySystem
         // directly.
         while (children.MoveNext(out var child))
         {
-            UpdateEntityRecursive(child.Value, _xformQuery.GetComponent(child.Value), coordinates, true, forceDirty);
+            UpdateEntityRecursive(child.Value, _metaQuery.GetComponent(child.Value), _xformQuery.GetComponent(child.Value), coordinates, true, forceDirty);
         }
     }
 
@@ -386,7 +389,7 @@ internal sealed partial class PvsSystem : EntitySystem
             pvsCollection.AddGrid(gridId);
         }
 
-        _entityPvsCollection.AddGlobalOverride(gridId, true, false);
+        _entityPvsCollection.AddGlobalOverride(_metaQuery.GetComponent(gridId).NetEntity, true, false);
     }
 
     private void OnMapDestroyed(MapChangedEvent e)
@@ -406,7 +409,7 @@ internal sealed partial class PvsSystem : EntitySystem
 
         if(e.Map == MapId.Nullspace) return;
         var uid = _mapManager.GetMapEntityId(e.Map);
-        _entityPvsCollection.AddGlobalOverride(uid, true, false);
+        _entityPvsCollection.AddGlobalOverride(_metaQuery.GetComponent(uid).NetEntity, true, false);
     }
 
     #endregion
@@ -533,14 +536,9 @@ internal sealed partial class PvsSystem : EntitySystem
         return (_chunkList, playerChunks, viewerEntities);
     }
 
-    private Dictionary<(uint visMask, IChunkIndexLocation location), (Dictionary<EntityUid, MetaDataComponent> metadata,
-        RobustTree<EntityUid> tree)?> _previousTrees = new();
-
-    private HashSet<(uint visMask, IChunkIndexLocation location)> _reusedTrees = new();
-
     public void RegisterNewPreviousChunkTrees(
         List<(uint, IChunkIndexLocation)> chunks,
-        (Dictionary<EntityUid, MetaDataComponent> metadata, RobustTree<EntityUid> tree)?[] trees,
+        (Dictionary<NetEntity, MetaDataComponent> metadata, RobustTree<NetEntity> tree)?[] trees,
         bool[] reuse)
     {
         // For any chunks able to re-used we'll chuck them in a dictionary for faster lookup.
@@ -584,9 +582,7 @@ internal sealed partial class PvsSystem : EntitySystem
     public bool TryCalculateChunk(
         IChunkIndexLocation chunkLocation,
         uint visMask,
-        EntityQuery<TransformComponent> transform,
-        EntityQuery<MetaDataComponent> metadata,
-        out (Dictionary<EntityUid, MetaDataComponent> mData, RobustTree<EntityUid> tree)? result)
+        out (Dictionary<NetEntity, MetaDataComponent> mData, RobustTree<NetEntity> tree)? result)
     {
         if (!_entityPvsCollection.IsDirty(chunkLocation) && _previousTrees.TryGetValue((visMask, chunkLocation), out var previousTree))
         {
@@ -613,11 +609,12 @@ internal sealed partial class PvsSystem : EntitySystem
         }
         var chunkSet = _chunkCachePool.Get();
         var tree = _treePool.Get();
-        foreach (var uid in chunk)
+        foreach (var netEntity in chunk)
         {
-            AddToChunkSetRecursively(in uid, visMask, tree, chunkSet, transform, metadata);
+            var uid = GetEntity(netEntity);
+            AddToChunkSetRecursively(in uid, in netEntity, visMask, tree, chunkSet);
 #if DEBUG
-            var xform = transform.GetComponent(uid);
+            var xform = _xformQuery.GetComponent(uid);
             if (chunkLocation is MapChunkLocation)
                 DebugTools.Assert(xform.GridUid == null || xform.GridUid == uid);
             else if (chunkLocation is GridChunkLocation)
@@ -649,51 +646,55 @@ internal sealed partial class PvsSystem : EntitySystem
         }
     }
 
-    private bool AddToChunkSetRecursively(in EntityUid uid, uint visMask, RobustTree<EntityUid> tree, Dictionary<EntityUid, MetaDataComponent> set, EntityQuery<TransformComponent> transform,
-        EntityQuery<MetaDataComponent> metadata)
+    private bool AddToChunkSetRecursively(in EntityUid uid, in NetEntity netEntity, uint visMask, RobustTree<NetEntity> tree, Dictionary<NetEntity, MetaDataComponent> set)
     {
-        if (set.ContainsKey(uid))
+        if (set.ContainsKey(netEntity))
             return true;
 
-        var mComp = metadata.GetComponent(uid);
+        var mComp = _metaQuery.GetComponent(uid);
 
         // TODO: Don't need to know about parents so no longer need to use bool for this method.
         // If the eye is missing ANY layer this entity or any of its parents belongs to, it is considered invisible.
         if ((visMask & mComp.VisibilityMask) != mComp.VisibilityMask)
             return false;
 
-        var xform = transform.GetComponent(uid);
+        var xform = _xformQuery.GetComponent(uid);
 
         // is this a map or grid?
         var isRoot = !xform.ParentUid.IsValid() || uid == xform.GridUid;
         if (isRoot)
         {
             DebugTools.Assert(_mapManager.IsGrid(uid) || _mapManager.IsMap(uid));
-            tree.Set(uid);
-            set.Add(uid, mComp);
+            tree.Set(netEntity);
+            set.Add(netEntity, mComp);
             return true;
         }
 
         DebugTools.Assert(!_mapManager.IsGrid(uid) && !_mapManager.IsMap(uid));
 
         var parent = xform.ParentUid;
-        if (!set.ContainsKey(parent) && //was the parent not yet added to toSend?
-            !AddToChunkSetRecursively(in parent, visMask, tree, set, transform, metadata)) //did we just fail to add the parent?
+        var parentNetEntity = _metaQuery.GetComponent(parent).NetEntity;
+
+        // TODO performance
+        // AddToChunkSetRecursively will result in a redundant set.ContainsKey() check.
+        // This can probably be avoided somehow
+        if (!set.ContainsKey(parentNetEntity) && //was the parent not yet added to toSend?
+            !AddToChunkSetRecursively(in parent, in parentNetEntity, visMask, tree, set)) //did we just fail to add the parent?
+        {
             return false; //we failed? suppose we dont get added either
+        }
 
         //i want it to crash here if it gets added double bc that shouldnt happen and will add alot of unneeded cycles
-        tree.Set(uid, parent);
-        set.Add(uid, mComp);
+        tree.Set(netEntity, parentNetEntity);
+        set.Add(netEntity, mComp);
         return true;
     }
 
-    internal (List<EntityState>? updates, List<EntityUid>? deletions, List<EntityUid>? leftPvs, GameTick fromTick)
+    internal (List<EntityState>? updates, List<NetEntity>? deletions, List<NetEntity>? leftPvs, GameTick fromTick)
         CalculateEntityStates(IPlayerSession session,
             GameTick fromTick,
             GameTick toTick,
-            EntityQuery<MetaDataComponent> mQuery,
-            EntityQuery<TransformComponent> tQuery,
-            (Dictionary<EntityUid, MetaDataComponent> metadata, RobustTree<EntityUid> tree)?[] chunks,
+            (Dictionary<NetEntity, MetaDataComponent> metadata, RobustTree<NetEntity> tree)?[] chunks,
             HashSet<int> visibleChunks,
             EntityUid[] viewers)
     {
@@ -712,7 +713,6 @@ internal sealed partial class PvsSystem : EntitySystem
             throw new Exception("Encountered non-empty object inside of _visSetPool. Was the same object returned to the pool more than once?");
 
         var deletions = _entityPvsCollection.GetDeletedIndices(fromTick);
-
         var entStateCount = 0;
 
         var stack = _stackPool.Get();
@@ -726,14 +726,15 @@ internal sealed partial class PvsSystem : EntitySystem
             // Each root nodes should simply be a map or a grid entity.
             DebugTools.Assert(cache.Value.tree.RootNodes.Count == 1,
                 $"Root node count is {cache.Value.tree.RootNodes.Count} instead of 1. Session: {session}");
-            var ent = cache.Value.tree.RootNodes.FirstOrDefault();
+            var nent = cache.Value.tree.RootNodes.FirstOrDefault();
+            var ent = GetEntity(nent);
             DebugTools.Assert(Exists(ent), $"Root node does not exist. Node {ent}. Session: {session}");
             DebugTools.Assert(HasComp<MapComponent>(ent) || HasComp<MapGridComponent>(ent));
 #endif
 
             foreach (var rootNode in cache.Value.tree.RootNodes)
             {
-                RecursivelyAddTreeNode(in rootNode, cache.Value.tree, lastAcked, lastSent, visibleEnts, lastSeen, cache.Value.metadata, stack, in fromTick,
+                RecursivelyAddTreeNode(in rootNode, cache.Value.tree, lastAcked, lastSent, visibleEnts, lastSeen, stack, in fromTick,
                         ref newEntityCount, ref enteredEntityCount, ref entStateCount,  in newEntityBudget, in enteredEntityBudget);
             }
         }
@@ -742,8 +743,9 @@ internal sealed partial class PvsSystem : EntitySystem
         var globalEnumerator = _entityPvsCollection.GlobalOverridesEnumerator;
         while (globalEnumerator.MoveNext())
         {
-            var uid = globalEnumerator.Current;
-            RecursivelyAddOverride(in uid, lastAcked, lastSent, visibleEnts, lastSeen, in mQuery, in tQuery, in fromTick,
+            var netEntity = globalEnumerator.Current;
+            var uid = GetEntity(netEntity);
+            RecursivelyAddOverride(in uid, lastAcked, lastSent, visibleEnts, lastSeen, in fromTick,
                 ref newEntityCount, ref enteredEntityCount, ref entStateCount, in newEntityBudget, in enteredEntityBudget);
         }
         globalEnumerator.Dispose();
@@ -752,8 +754,9 @@ internal sealed partial class PvsSystem : EntitySystem
         var globalRecursiveEnumerator = _entityPvsCollection.GlobalRecursiveOverridesEnumerator;
         while (globalRecursiveEnumerator.MoveNext())
         {
-            var uid = globalRecursiveEnumerator.Current;
-            RecursivelyAddOverride(in uid, lastAcked, lastSent, visibleEnts, lastSeen, in mQuery, in tQuery, in fromTick,
+            var netEntity = globalRecursiveEnumerator.Current;
+            var uid = GetEntity(netEntity);
+            RecursivelyAddOverride(in uid, lastAcked, lastSent, visibleEnts, lastSeen, in fromTick,
                 ref newEntityCount, ref enteredEntityCount, ref entStateCount, in newEntityBudget, in enteredEntityBudget, true);
         }
         globalRecursiveEnumerator.Dispose();
@@ -761,15 +764,16 @@ internal sealed partial class PvsSystem : EntitySystem
         var localEnumerator = _entityPvsCollection.GetElementsForSession(session);
         while (localEnumerator.MoveNext())
         {
-            var uid = localEnumerator.Current;
-            RecursivelyAddOverride(in uid, lastAcked, lastSent, visibleEnts, lastSeen, in mQuery, in tQuery, in fromTick,
+            var netEntity = localEnumerator.Current;
+            var uid = GetEntity(netEntity);
+            RecursivelyAddOverride(in uid, lastAcked, lastSent, visibleEnts, lastSeen,in fromTick,
                 ref newEntityCount, ref enteredEntityCount, ref entStateCount, in newEntityBudget, in enteredEntityBudget);
         }
         localEnumerator.Dispose();
 
         foreach (var viewerEntity in viewers)
         {
-            RecursivelyAddOverride(in viewerEntity, lastAcked, lastSent, visibleEnts, lastSeen, in mQuery, in tQuery, in fromTick,
+            RecursivelyAddOverride(in viewerEntity, lastAcked, lastSent, visibleEnts, lastSeen, in fromTick,
                 ref newEntityCount, ref enteredEntityCount, ref entStateCount, in newEntityBudget, in enteredEntityBudget);
         }
 
@@ -777,27 +781,32 @@ internal sealed partial class PvsSystem : EntitySystem
         RaiseLocalEvent(ref expandEvent);
         foreach (var entityUid in expandEvent.Entities)
         {
-            RecursivelyAddOverride(in entityUid, lastAcked, lastSent, visibleEnts, lastSeen, in mQuery, in tQuery, in fromTick,
+            RecursivelyAddOverride(in entityUid, lastAcked, lastSent, visibleEnts, lastSeen, in fromTick,
                 ref newEntityCount, ref enteredEntityCount, ref entStateCount, in newEntityBudget, in enteredEntityBudget);
         }
 
         foreach (var entityUid in expandEvent.RecursiveEntities)
         {
-            RecursivelyAddOverride(in entityUid, lastAcked, lastSent, visibleEnts, lastSeen, in mQuery, in tQuery, in fromTick,
+            RecursivelyAddOverride(in entityUid, lastAcked, lastSent, visibleEnts, lastSeen,in fromTick,
                 ref newEntityCount, ref enteredEntityCount, ref entStateCount, in newEntityBudget, in enteredEntityBudget, true);
         }
 
         var entityStates = new List<EntityState>(entStateCount);
 
-        foreach (var (uid, visiblity) in visibleEnts)
+        foreach (var (netEntity, visiblity) in visibleEnts)
         {
+            var uid = GetEntity(netEntity);
+
+#if DEBUG
             // if an entity is visible, its parents should always be visible.
-            DebugTools.Assert((tQuery.GetComponent(uid).ParentUid is not { Valid: true } parent) || visibleEnts.ContainsKey(parent),
+            DebugTools.Assert((_xformQuery.GetComponent(uid).ParentUid is not { Valid: true } parent) ||
+                              visibleEnts.ContainsKey(_metaQuery.GetComponent(parent).NetEntity),
                 $"Attempted to send an entity without sending it's parents. Entity: {ToPrettyString(uid)}.");
+#endif
 
             if (sessionData.RequestedFull)
             {
-                entityStates.Add(GetFullEntityState(session, uid, mQuery.GetComponent(uid)));
+                entityStates.Add(GetFullEntityState(session, uid, _metaQuery.GetComponent(uid)));
                 continue;
             }
 
@@ -805,8 +814,8 @@ internal sealed partial class PvsSystem : EntitySystem
                 continue;
 
             var entered = visiblity == PvsEntityVisibility.Entered;
-            var entFromTick = entered ? lastSeen.GetValueOrDefault(uid) : fromTick;
-            var state = GetEntityState(session, uid, entFromTick, mQuery.GetComponent(uid));
+            var entFromTick = entered ? lastSeen.GetValueOrDefault(netEntity) : fromTick;
+            var state = GetEntityState(session, uid, entFromTick, _metaQuery.GetComponent(uid));
 
             if (entered || !state.Empty)
                 entityStates.Add(state);
@@ -850,31 +859,30 @@ internal sealed partial class PvsSystem : EntitySystem
     ///     Figure out what entities are no longer visible to the client. These entities are sent reliably to the client
     ///     in a separate net message.
     /// </summary>
-    private List<EntityUid>? ProcessLeavePVS(
-        Dictionary<EntityUid, PvsEntityVisibility> visibleEnts,
-        Dictionary<EntityUid, PvsEntityVisibility>? lastSent)
+    private List<NetEntity>? ProcessLeavePVS(
+        Dictionary<NetEntity, PvsEntityVisibility> visibleEnts,
+        Dictionary<NetEntity, PvsEntityVisibility>? lastSent)
     {
         if (lastSent == null)
             return null;
 
-        var leftView = new List<EntityUid>();
-        foreach (var uid in lastSent.Keys)
+        var leftView = new List<NetEntity>();
+        foreach (var netEntity in lastSent.Keys)
         {
-            if (!visibleEnts.ContainsKey(uid))
-                leftView.Add(uid);
+            if (!visibleEnts.ContainsKey(netEntity))
+                leftView.Add(netEntity);
         }
 
         return leftView.Count > 0 ? leftView : null;
     }
 
-    private void RecursivelyAddTreeNode(in EntityUid nodeIndex,
-        RobustTree<EntityUid> tree,
-        Dictionary<EntityUid, PvsEntityVisibility>? lastAcked,
-        Dictionary<EntityUid, PvsEntityVisibility>? lastSent,
-        Dictionary<EntityUid, PvsEntityVisibility> toSend,
-        Dictionary<EntityUid, GameTick> lastSeen,
-        Dictionary<EntityUid, MetaDataComponent> metaDataCache,
-        Stack<EntityUid> stack,
+    private void RecursivelyAddTreeNode(in NetEntity nodeIndex,
+        RobustTree<NetEntity> tree,
+        Dictionary<NetEntity, PvsEntityVisibility>? lastAcked,
+        Dictionary<NetEntity, PvsEntityVisibility>? lastSent,
+        Dictionary<NetEntity, PvsEntityVisibility> toSend,
+        Dictionary<NetEntity, GameTick> lastSeen,
+        Stack<NetEntity> stack,
         in GameTick fromTick,
         ref int newEntityCount,
         ref int enteredEntityCount,
@@ -899,7 +907,8 @@ internal sealed partial class PvsSystem : EntitySystem
                 if (!shouldAdd)
                     continue;
 
-                AddToSendSet(in currentNodeIndex, metaDataCache[currentNodeIndex], toSend, fromTick, in entered, ref entStateCount);
+                var entity = GetEntity(currentNodeIndex);
+                AddToSendSet(in currentNodeIndex, _metaQuery.GetComponent(entity), toSend, fromTick, in entered, ref entStateCount);
             }
 
             var node = tree[currentNodeIndex];
@@ -914,12 +923,10 @@ internal sealed partial class PvsSystem : EntitySystem
     }
 
     public bool RecursivelyAddOverride(in EntityUid uid,
-        Dictionary<EntityUid, PvsEntityVisibility>? lastAcked,
-        Dictionary<EntityUid, PvsEntityVisibility>? lastSent,
-        Dictionary<EntityUid, PvsEntityVisibility> toSend,
-        Dictionary<EntityUid, GameTick> lastSeen,
-        in EntityQuery<MetaDataComponent> metaQuery,
-        in EntityQuery<TransformComponent> transQuery,
+        Dictionary<NetEntity, PvsEntityVisibility>? lastAcked,
+        Dictionary<NetEntity, PvsEntityVisibility>? lastSent,
+        Dictionary<NetEntity, PvsEntityVisibility> toSend,
+        Dictionary<NetEntity, GameTick> lastSeen,
         in GameTick fromTick,
         ref int newEntityCount,
         ref int enteredEntityCount,
@@ -933,25 +940,31 @@ internal sealed partial class PvsSystem : EntitySystem
         if (!uid.IsValid())
             return false;
 
-        var xform = transQuery.GetComponent(uid);
+        var xform = _xformQuery.GetComponent(uid);
         var parent = xform.ParentUid;
-        if (parent.IsValid() && !RecursivelyAddOverride(in parent, lastAcked, lastSent, toSend, lastSeen, in metaQuery, in transQuery, in fromTick,
-                ref newEntityCount, ref enteredEntityCount, ref entStateCount, in newEntityBudget, in enteredEntityBudget))
+        if (parent.IsValid() && !RecursivelyAddOverride(in parent, lastAcked, lastSent, toSend, lastSeen, in fromTick,
+                ref newEntityCount, ref enteredEntityCount, ref entStateCount, in newEntityBudget,
+                in enteredEntityBudget))
+        {
             return false;
+        }
+
+        var metadata = _metaQuery.GetComponent(uid);
+        var netEntity = GetNetEntity(uid, metadata);
 
         //did we already get added?
         // Note that we check this AFTER adding parents. This is because while this entity may already have been added
         // to the toSend set, it doesn't guarantee that its parents have been. E.g., if a player ghost just teleported
         // to follow a far away entity, the player's own entity is still being sent, but we need to ensure that we also
         // send the new parents, which may otherwise be delayed because of the PVS budget..
-        if (!toSend.ContainsKey(uid))
+        if (!toSend.ContainsKey(netEntity))
         {
             // TODO PERFORMANCE.
             // ProcessEntry() unnecessarily checks lastSent.ContainsKey() and maybe lastSeen.Contains(). Given that at this
             // point the budgets are just ignored, this should just bypass those checks. But then again 99% of the time this
             // is just the player's own entity + maybe a singularity. So currently not all that performance intensive.
-            var (entered, _) = ProcessEntry(in uid, lastAcked, lastSent, lastSeen, ref newEntityCount, ref enteredEntityCount, newEntityBudget, enteredEntityBudget);
-            AddToSendSet(in uid, metaQuery.GetComponent(uid), toSend, fromTick, in entered, ref entStateCount);
+            var (entered, _) = ProcessEntry(in netEntity, lastAcked, lastSent, lastSeen, ref newEntityCount, ref enteredEntityCount, newEntityBudget, enteredEntityBudget);
+            AddToSendSet(in netEntity, _metaQuery.GetComponent(uid), toSend, fromTick, in entered, ref entStateCount);
         }
 
         if (addChildren)
@@ -964,10 +977,10 @@ internal sealed partial class PvsSystem : EntitySystem
     }
 
     private void RecursivelyAddChildren(TransformComponent xform,
-        Dictionary<EntityUid, PvsEntityVisibility>? lastAcked,
-        Dictionary<EntityUid, PvsEntityVisibility>? lastSent,
-        Dictionary<EntityUid, PvsEntityVisibility> toSend,
-        Dictionary<EntityUid, GameTick> lastSeen,
+        Dictionary<NetEntity, PvsEntityVisibility>? lastAcked,
+        Dictionary<NetEntity, PvsEntityVisibility>? lastSent,
+        Dictionary<NetEntity, PvsEntityVisibility> toSend,
+        Dictionary<NetEntity, GameTick> lastSeen,
         in GameTick fromTick,
         ref int newEntityCount,
         ref int enteredEntityCount,
@@ -980,12 +993,15 @@ internal sealed partial class PvsSystem : EntitySystem
             if (!_xformQuery.TryGetComponent(child, out var childXform))
                 continue;
 
-            if (!toSend.ContainsKey(child))
+            var metadata = _metaQuery.GetComponent(child);
+            var childNetEntity = GetNetEntity(child, metadata);
+
+            if (!toSend.ContainsKey(childNetEntity))
             {
-                var (entered, _) = ProcessEntry(in child, lastAcked, lastSent, lastSeen, ref newEntityCount,
+                var (entered, _) = ProcessEntry(in childNetEntity, lastAcked, lastSent, lastSeen, ref newEntityCount,
                     ref enteredEntityCount, newEntityBudget, enteredEntityBudget);
 
-                AddToSendSet(in child, _metaQuery.GetComponent(child), toSend, fromTick, in entered, ref entStateCount);
+                AddToSendSet(in childNetEntity, metadata, toSend, fromTick, in entered, ref entStateCount);
             }
 
             RecursivelyAddChildren(childXform, lastAcked, lastSent, toSend, lastSeen, fromTick, ref newEntityCount,
@@ -993,19 +1009,20 @@ internal sealed partial class PvsSystem : EntitySystem
         }
     }
 
-    private (bool Entered, bool ShouldAdd) ProcessEntry(in EntityUid uid,
-        Dictionary<EntityUid, PvsEntityVisibility>? lastAcked,
-        Dictionary<EntityUid, PvsEntityVisibility>? lastSent,
-        Dictionary<EntityUid, GameTick> lastSeen,
+    private (bool Entered, bool ShouldAdd) ProcessEntry(
+        in NetEntity netEntity,
+        Dictionary<NetEntity, PvsEntityVisibility>? lastAcked,
+        Dictionary<NetEntity, PvsEntityVisibility>? lastSent,
+        Dictionary<NetEntity, GameTick> lastSeen,
         ref int newEntityCount,
         ref int enteredEntityCount,
         in int newEntityBudget,
         in int enteredEntityBudget)
     {
-        var enteredSinceLastSent = lastSent == null || !lastSent.ContainsKey(uid);
+        var enteredSinceLastSent = lastSent == null || !lastSent.ContainsKey(netEntity);
 
         var entered = enteredSinceLastSent || // OR, entered since last ack:
-                        lastAcked == null || !lastAcked.ContainsKey(uid);
+                        lastAcked == null || !lastAcked.ContainsKey(netEntity);
 
         // If the entity is entering, but we already sent this entering entity in the last message, we won't add it to
         // the budget. Chances are the packet will arrive in a nice and orderly fashion, and the client will stick to
@@ -1020,25 +1037,25 @@ internal sealed partial class PvsSystem : EntitySystem
                 return (entered, false);
 
             enteredEntityCount++;
-            if (!lastSeen.ContainsKey(uid))
+            if (!lastSeen.ContainsKey(netEntity))
                 newEntityCount++;
         }
 
         return (entered, true);
     }
 
-    private void AddToSendSet(in EntityUid uid, MetaDataComponent metaDataComponent, Dictionary<EntityUid, PvsEntityVisibility> toSend, GameTick fromTick, in bool entered, ref int entStateCount)
+    private void AddToSendSet(in NetEntity netEntity, MetaDataComponent metaDataComponent, Dictionary<NetEntity, PvsEntityVisibility> toSend, GameTick fromTick, in bool entered, ref int entStateCount)
     {
         if (metaDataComponent.EntityLifeStage >= EntityLifeStage.Terminating)
         {
-            var rep = new EntityStringRepresentation(uid, metaDataComponent.EntityDeleted, metaDataComponent.EntityName, metaDataComponent.EntityPrototype?.ID);
+            var rep = new EntityStringRepresentation(GetEntity(netEntity), metaDataComponent.EntityDeleted, metaDataComponent.EntityName, metaDataComponent.EntityPrototype?.ID);
             Log.Error($"Attempted to add a deleted entity to PVS send set: '{rep}'. Trace:\n{Environment.StackTrace}");
             return;
         }
 
         if (entered)
         {
-            toSend.Add(uid, PvsEntityVisibility.Entered);
+            toSend.Add(netEntity, PvsEntityVisibility.Entered);
             entStateCount++;
             return;
         }
@@ -1046,22 +1063,22 @@ internal sealed partial class PvsSystem : EntitySystem
         if (metaDataComponent.EntityLastModifiedTick <= fromTick)
         {
             //entity has been sent before and hasnt been updated since
-            toSend.Add(uid, PvsEntityVisibility.StayedUnchanged);
+            toSend.Add(netEntity, PvsEntityVisibility.StayedUnchanged);
             return;
         }
 
         //add us
-        toSend.Add(uid, PvsEntityVisibility.StayedChanged);
+        toSend.Add(netEntity, PvsEntityVisibility.StayedChanged);
         entStateCount++;
     }
 
     /// <summary>
     ///     Gets all entity states that have been modified after and including the provided tick.
     /// </summary>
-    public (List<EntityState>?, List<EntityUid>?, GameTick fromTick) GetAllEntityStates(ICommonSession? player, GameTick fromTick, GameTick toTick)
+    public (List<EntityState>?, List<NetEntity>?, GameTick fromTick) GetAllEntityStates(ICommonSession? player, GameTick fromTick, GameTick toTick)
     {
         List<EntityState>? stateEntities;
-        var toSend = _uidSetPool.Get();
+        var toSend = new HashSet<EntityUid>();
         DebugTools.Assert(toSend.Count == 0);
         bool enumerateAll = false;
 
@@ -1096,7 +1113,7 @@ internal sealed partial class PvsSystem : EntitySystem
 
                 if (state.Empty)
                 {
-                    Log.Error($@"{nameof(GetEntityState)} returned an empty state while enumerating entities. 
+                    Log.Error($@"{nameof(GetEntityState)} returned an empty state while enumerating entities.
 Tick: {fromTick}--{_gameTiming.CurTick}
 Entity: {ToPrettyString(uid)}
 Last modified: {md.EntityLastModifiedTick}
@@ -1163,7 +1180,6 @@ Transform last modified: {Transform(uid).LastModifiedTick}");
             }
         }
 
-        _uidSetPool.Return(toSend);
         var deletions = _entityPvsCollection.GetDeletedIndices(fromTick);
 
         if (stateEntities.Count == 0)
@@ -1221,7 +1237,8 @@ Transform last modified: {Transform(uid).LastModifiedTick}");
         }
 
         DebugTools.Assert(meta.EntityLastModifiedTick >= meta.LastComponentRemoved);
-        var entState = new EntityState(entityUid, changed, meta.EntityLastModifiedTick, netComps);
+        DebugTools.Assert(GetEntity(meta.NetEntity) == entityUid);
+        var entState = new EntityState(meta.NetEntity, changed, meta.EntityLastModifiedTick, netComps);
 
         return entState;
     }
@@ -1253,7 +1270,7 @@ Transform last modified: {Transform(uid).LastModifiedTick}");
             netComps.Add(netId);
         }
 
-        var entState = new EntityState(entityUid, changed, meta.EntityLastModifiedTick, netComps);
+        var entState = new EntityState(meta.NetEntity, changed, meta.EntityLastModifiedTick, netComps);
 
         return entState;
     }
@@ -1263,14 +1280,13 @@ Transform last modified: {Transform(uid).LastModifiedTick}");
         if (session.Status != SessionStatus.InGame)
             return Array.Empty<EntityUid>();
 
-        var viewers = _uidSetPool.Get();
+        var viewers = new HashSet<EntityUid>();
 
         if (session.AttachedEntity != null)
         {
             // Fast path
             if (session is IPlayerSession { ViewSubscriptionCount: 0 })
             {
-                _uidSetPool.Return(viewers);
                 return new[] { session.AttachedEntity.Value };
             }
 
@@ -1288,7 +1304,6 @@ Transform last modified: {Transform(uid).LastModifiedTick}");
 
         var viewerArray = viewers.ToArray();
 
-        _uidSetPool.Return(viewers);
         return viewerArray;
     }
 
@@ -1336,23 +1351,23 @@ Transform last modified: {Transform(uid).LastModifiedTick}");
         /// <summary>
         /// All <see cref="EntityUid"/>s that this session saw during the last <see cref="DirtyBufferSize"/> ticks.
         /// </summary>
-        public readonly OverflowDictionary<GameTick, Dictionary<EntityUid, PvsEntityVisibility>> SentEntities = new(DirtyBufferSize);
+        public readonly OverflowDictionary<GameTick, Dictionary<NetEntity, PvsEntityVisibility>> SentEntities = new(DirtyBufferSize);
 
         /// <summary>
         ///     The most recently acked entities
         /// </summary>
-        public (GameTick Tick, Dictionary<EntityUid, PvsEntityVisibility> Data)? LastAcked;
+        public (GameTick Tick, Dictionary<NetEntity, PvsEntityVisibility> Data)? LastAcked;
 
         /// <summary>
         ///     Stores the last tick at which a given entity was acked by a player. Used to avoid re-sending the whole entity
         ///     state when an item re-enters PVS.
         /// </summary>
-        public readonly Dictionary<EntityUid, GameTick> LastSeenAt = new();
+        public readonly Dictionary<NetEntity, GameTick> LastSeenAt = new();
 
         /// <summary>
         ///     <see cref="SentEntities"/> overflow in case a player's last ack is more than <see cref="DirtyBufferSize"/> ticks behind the current tick.
         /// </summary>
-        public (GameTick Tick, Dictionary<EntityUid, PvsEntityVisibility> SentEnts)? Overflow;
+        public (GameTick Tick, Dictionary<NetEntity, PvsEntityVisibility> SentEnts)? Overflow;
 
         /// <summary>
         ///     If true, the client has explicitly requested a full state. Unlike the first state, we will send them

Robust.Server/GameStates/ServerGameStateManager.cs

@@ -63,7 +63,7 @@ namespace Robust.Server.GameStates
         public ushort TransformNetId { get; set; }
 
         public Action<ICommonSession, GameTick>? ClientAck { get; set; }
-        public Action<ICommonSession, GameTick, EntityUid?>? ClientRequestFull { get; set; }
+        public Action<ICommonSession, GameTick, NetEntity?>? ClientRequestFull { get; set; }
 
         public void PostInject()
         {
@@ -134,7 +134,7 @@ namespace Robust.Server.GameStates
             if (!_playerManager.TryGetSessionById(msg.MsgChannel.UserId, out var session))
                 return;
 
-            EntityUid? ent = msg.MissingEntity.IsValid() ? msg.MissingEntity : null;
+            NetEntity? ent = msg.MissingEntity.IsValid() ? msg.MissingEntity : null;
             ClientRequestFull?.Invoke(session, msg.Tick, ent);
         }
 
@@ -245,7 +245,7 @@ namespace Robust.Server.GameStates
         {
             public HashSet<int>[] PlayerChunks;
             public EntityUid[][] ViewerEntities;
-            public (Dictionary<EntityUid, MetaDataComponent> metadata, RobustTree<EntityUid> tree)?[] ChunkCache;
+            public (Dictionary<NetEntity, MetaDataComponent> metadata, RobustTree<NetEntity> tree)?[] ChunkCache;
         }
 
         private PvsData? GetPVSData(IPlayerSession[] players)
@@ -255,13 +255,11 @@ namespace Robust.Server.GameStates
             var chunksCount = chunks.Count;
             var chunkBatches = (int)MathF.Ceiling((float)chunksCount / ChunkBatchSize);
             var chunkCache =
-                new (Dictionary<EntityUid, MetaDataComponent> metadata, RobustTree<EntityUid> tree)?[chunksCount];
+                new (Dictionary<NetEntity, MetaDataComponent> metadata, RobustTree<NetEntity> tree)?[chunksCount];
 
             // Update the reused trees sequentially to avoid having to lock the dictionary per chunk.
             var reuse = ArrayPool<bool>.Shared.Rent(chunksCount);
 
-            var transformQuery = _entityManager.GetEntityQuery<TransformComponent>();
-            var metadataQuery = _entityManager.GetEntityQuery<MetaDataComponent>();
             Parallel.For(0, chunkBatches,
                 new ParallelOptions { MaxDegreeOfParallelism = _parallelMgr.ParallelProcessCount },
                 i =>
@@ -272,8 +270,7 @@ namespace Robust.Server.GameStates
                     for (var j = start; j < end; ++j)
                     {
                         var (visMask, chunkIndexLocation) = chunks[j];
-                        reuse[j] = _pvs.TryCalculateChunk(chunkIndexLocation, visMask, transformQuery, metadataQuery,
-                            out var chunk);
+                        reuse[j] = _pvs.TryCalculateChunk(chunkIndexLocation, visMask, out var chunk);
                         chunkCache[j] = chunk;
 
 #if DEBUG
@@ -283,7 +280,8 @@ namespace Robust.Server.GameStates
                         // Each root nodes should simply be a map or a grid entity.
                         DebugTools.Assert(chunk.Value.tree.RootNodes.Count == 1,
                             $"Root node count is {chunk.Value.tree.RootNodes.Count} instead of 1.");
-                        var ent = chunk.Value.tree.RootNodes.FirstOrDefault();
+                        var nent = chunk.Value.tree.RootNodes.FirstOrDefault();
+                        var ent = _entityManager.GetEntity(nent);
                         DebugTools.Assert(_entityManager.EntityExists(ent), $"Root node does not exist. Node {ent}.");
                         DebugTools.Assert(_entityManager.HasComponent<MapComponent>(ent)
                                           || _entityManager.HasComponent<MapGridComponent>(ent));
@@ -313,9 +311,9 @@ namespace Robust.Server.GameStates
             var channel = session.ConnectedClient;
             var sessionData = _pvs.PlayerData[session];
             var lastAck = sessionData.LastReceivedAck;
-            List<EntityUid>? leftPvs = null;
+            List<NetEntity>? leftPvs = null;
             List<EntityState>? entStates;
-            List<EntityUid>? deletions;
+            List<NetEntity>? deletions;
             GameTick fromTick;
 
             DebugTools.Assert(_pvs.CullingEnabled == (pvsData != null));
@@ -325,8 +323,6 @@ namespace Robust.Server.GameStates
                     session,
                     lastAck,
                     _gameTiming.CurTick,
-                    mQuery,
-                    tQuery,
                     pvsData.Value.ChunkCache,
                     pvsData.Value.PlayerChunks[i],
                     pvsData.Value.ViewerEntities[i]);

Robust.Server/Physics/GridFixtureSystem.cs

@@ -130,7 +130,7 @@ namespace Robust.Server.Physics
 
             var msg = new ChunkSplitDebugMessage
             {
-                Grid = uid,
+                Grid = GetNetEntity(uid),
             };
 
             foreach (var (index, group) in _nodes[uid])

Robust.Server/Physics/JointSystem.cs

@@ -21,9 +21,9 @@ public sealed class JointSystem : SharedJointSystem
 
         foreach (var (id, joint) in component.Joints)
         {
-            states.Add(id, joint.GetState());
+            states.Add(id, joint.GetState(EntityManager));
         }
 
-        args.State = new JointComponentState(component.Relay, states);
+        args.State = new JointComponentState(GetNetEntity(component.Relay), states);
     }
 }

Robust.Server/Placement/PlacementManager.cs

@@ -98,8 +98,10 @@ namespace Robust.Server.Placement
                 return;
 
             //TODO: Distance check, so you can't place things off of screen.
+            // I don't think that's this manager's biggest problem
 
-            var coordinates = msg.EntityCoordinates;
+            var netCoordinates = msg.NetCoordinates;
+            var coordinates = _entityManager.GetCoordinates(netCoordinates);
 
             if (!coordinates.IsValid(_entityManager))
             {
@@ -211,17 +213,19 @@ namespace Robust.Server.Placement
         private void HandleEntRemoveReq(MsgPlacement msg)
         {
             //TODO: Some form of admin check
-            if (!_entityManager.EntityExists(msg.EntityUid))
+            var entity = _entityManager.GetEntity(msg.EntityUid);
+
+            if (!_entityManager.EntityExists(entity))
                 return;
 
-            var placementEraseEvent = new PlacementEntityEvent(msg.EntityUid, _entityManager.GetComponent<TransformComponent>(msg.EntityUid).Coordinates, PlacementEventAction.Erase, msg.MsgChannel.UserId);
+            var placementEraseEvent = new PlacementEntityEvent(entity, _entityManager.GetComponent<TransformComponent>(entity).Coordinates, PlacementEventAction.Erase, msg.MsgChannel.UserId);
             _entityManager.EventBus.RaiseEvent(EventSource.Local, placementEraseEvent);
-            _entityManager.DeleteEntity(msg.EntityUid);
+            _entityManager.DeleteEntity(entity);
         }
 
         private void HandleRectRemoveReq(MsgPlacement msg)
         {
-            EntityCoordinates start = msg.EntityCoordinates;
+            EntityCoordinates start = _entityManager.GetCoordinates(msg.NetCoordinates);
             Vector2 rectSize = msg.RectSize;
             foreach (EntityUid entity in EntitySystem.Get<EntityLookupSystem>().GetEntitiesIntersecting(start.GetMapId(_entityManager),
                 new Box2(start.Position, start.Position + rectSize)))

Robust.Server/Player/PlayerSession.cs

@@ -210,7 +210,7 @@ namespace Robust.Server.Player
         {
             PlayerState.Status = Status;
             PlayerState.Name = Name;
-            PlayerState.ControlledEntity = AttachedEntity;
+            PlayerState.ControlledEntity = IoCManager.Resolve<IEntityManager>().GetNetEntity(AttachedEntity);
 
             _playerManager.Dirty();
         }

Robust.Server/ViewVariables/ServerViewVariablesManager.cs

@@ -125,8 +125,10 @@ namespace Robust.Server.ViewVariables
                 case ViewVariablesComponentSelector componentSelector:
                 {
                     var compType = _reflectionManager.GetType(componentSelector.ComponentType);
+                    var entity = _entityManager.GetEntity(componentSelector.Entity);
+
                     if (compType == null ||
-                        !_entityManager.TryGetComponent(componentSelector.Entity, compType, out var component))
+                        !_entityManager.TryGetComponent(entity, compType, out var component))
                     {
                         Deny(ViewVariablesResponseCode.NoObject);
                         return;
@@ -137,7 +139,9 @@ namespace Robust.Server.ViewVariables
                 }
                 case ViewVariablesEntitySelector entitySelector:
                 {
-                    if (!_entityManager.EntityExists(entitySelector.Entity))
+                    var entity = _entityManager.GetEntity(entitySelector.Entity);
+
+                    if (!_entityManager.EntityExists(entity))
                     {
                         Deny(ViewVariablesResponseCode.NoObject);
                         return;

Robust.Server/ViewVariables/Traits/ViewVariablesTraitEntity.cs

@@ -14,7 +14,8 @@ namespace Robust.Server.ViewVariables.Traits
 
         public ViewVariablesTraitEntity(IViewVariablesSession session) : base(session)
         {
-            _entity = (EntityUid) Session.Object;
+            var netEntity = (NetEntity) Session.Object;
+            _entity = IoCManager.Resolve<IEntityManager>().GetEntity(netEntity);
         }
 
         public override ViewVariablesBlob? DataRequest(ViewVariablesRequest viewVariablesRequest)

Robust.Server/ViewVariables/Traits/ViewVariablesTraitMembers.cs

@@ -2,6 +2,7 @@ using System;
 using System.Collections.Generic;
 using System.Linq;
 using System.Reflection;
+using Robust.Shared.GameObjects;
 using Robust.Shared.IoC;
 using Robust.Shared.Log;
 using Robust.Shared.Prototypes;
@@ -27,10 +28,11 @@ namespace Robust.Server.ViewVariables.Traits
             if (messageRequestMeta is ViewVariablesRequestMembers)
             {
                 var members = new List<(MemberData mData, MemberInfo mInfo)>();
+                var obj = Session.Object;
+                var objType = Session.ObjectType;
 
-                foreach (var property in Session.ObjectType.GetAllProperties())
+                foreach (var property in objType.GetAllProperties())
                 {
-
                     if (!ViewVariablesUtility.TryGetViewVariablesAccess(property, out var access))
                     {
                         continue;
@@ -53,7 +55,7 @@ namespace Robust.Server.ViewVariables.Traits
                     _members.Add(property);
                 }
 
-                foreach (var field in Session.ObjectType.GetAllFields())
+                foreach (var field in objType.GetAllFields())
                 {
                     if (!ViewVariablesUtility.TryGetViewVariablesAccess(field, out var access))
                     {
@@ -66,7 +68,7 @@ namespace Robust.Server.ViewVariables.Traits
                         Name = field.Name,
                         Type = field.FieldType.AssemblyQualifiedName,
                         TypePretty = PrettyPrint.PrintUserFacingTypeShort(field.FieldType, 2),
-                        Value = field.GetValue(Session.Object),
+                        Value = field.GetValue(obj),
                         PropertyIndex = _members.Count
                     }, field));
 

Robust.Shared.CompNetworkGenerator/ComponentNetworkGenerator.cs

@@ -14,9 +14,14 @@ namespace Robust.Shared.CompNetworkGenerator
     {
         private const string ClassAttributeName = "Robust.Shared.Analyzers.AutoGenerateComponentStateAttribute";
         private const string MemberAttributeName = "Robust.Shared.Analyzers.AutoNetworkedFieldAttribute";
+        private const string GlobalEntityUidName = "global::Robust.Shared.GameObjects.EntityUid";
+        private const string GlobalNullableEntityUidName = "global::Robust.Shared.GameObjects.EntityUid?";
+        private const string GlobalEntityCoordinatesName = "global::Robust.Shared.Map.EntityCoordinates?";
+        private const string GlobalNullableEntityCoordinatesName = "global::Robust.Shared.Map.EntityCoordinates";
 
         private static string GenerateSource(in GeneratorExecutionContext context, INamedTypeSymbol classSymbol, CSharpCompilation comp, bool raiseAfterAutoHandle)
         {
+            // Debugger.Launch();
             var nameSpace = classSymbol.ContainingNamespace.ToDisplayString();
             var componentName = classSymbol.Name;
             var stateName = $"{componentName}_AutoState";
@@ -115,27 +120,59 @@ namespace Robust.Shared.CompNetworkGenerator
 
             foreach (var (type, name, attribute) in fields)
             {
-                stateFields.Append($@"
-        public {type.ToDisplayString(SymbolDisplayFormat.FullyQualifiedFormat)} {name} = default!;");
+                var typeDisplayStr = type.ToDisplayString(SymbolDisplayFormat.FullyQualifiedFormat);
+                var nullable = type.NullableAnnotation == NullableAnnotation.Annotated;
+                var nullableAnnotation = nullable ? "?" : string.Empty;
 
-                // get first ctor arg of the field attribute, which determines whether the field should be cloned
-                // (like if its a dict or list)
-                if (attribute.ConstructorArguments[0].Value is bool val && val)
+                switch (typeDisplayStr)
                 {
-                    getStateInit.Append($@"
+                    case GlobalEntityUidName:
+                    case GlobalNullableEntityUidName:
+                        stateFields.Append($@"
+        public NetEntity{nullableAnnotation} {name} = default!;");
+
+                        getStateInit.Append($@"
+                {name} = GetNetEntity(component.{name}),");
+                        handleStateSetters.Append($@"
+            component.{name} = EnsureEntity<{componentName}>(state.{name}, uid);");
+
+                        break;
+                    case GlobalEntityCoordinatesName:
+                    case GlobalNullableEntityCoordinatesName:
+                        stateFields.Append($@"
+        public NetCoordinates{nullableAnnotation} {name} = default!;");
+
+                        getStateInit.Append($@"
+                {name} = GetNetCoordinates(component.{name}),");
+                        handleStateSetters.Append($@"
+            component.{name} = EnsureCoordinates<{componentName}>(state.{name}, uid);");
+
+                        break;
+                    default:
+                        stateFields.Append($@"
+        public {typeDisplayStr} {name} = default!;");
+
+                        if (attribute.ConstructorArguments[0].Value is bool val && val)
+                        {
+                            // get first ctor arg of the field attribute, which determines whether the field should be cloned
+                            // (like if its a dict or list)
+                            getStateInit.Append($@"
                 {name} = component.{name},");
 
-                    handleStateSetters.Append($@"
+                            handleStateSetters.Append($@"
             if (state.{name} != null)
                 component.{name} = new(state.{name});");
-                }
-                else
-                {
-                    getStateInit.Append($@"
+                        }
+                        else
+                        {
+                            getStateInit.Append($@"
                 {name} = component.{name},");
 
-                    handleStateSetters.Append($@"
+                            handleStateSetters.Append($@"
             component.{name} = state.{name};");
+                        }
+
+                        break;
                 }
             }
 
@@ -153,6 +190,7 @@ using Robust.Shared.GameStates;
 using Robust.Shared.GameObjects;
 using Robust.Shared.Analyzers;
 using Robust.Shared.Serialization;
+using Robust.Shared.Map;
 
 namespace {nameSpace};
 

Robust.Shared/Console/Commands/DumpEventTablesCommand.cs

@@ -19,7 +19,9 @@ internal sealed class DumpEventTablesCommand : LocalizedCommands
             return;
         }
 
-        if (!EntityUid.TryParse(args[0], out var entity) || !_entities.EntityExists(entity))
+        if (!NetEntity.TryParse(args[0], out var entityNet) ||
+            !_entities.TryGetEntity(entityNet, out var entity) ||
+            !_entities.EntityExists(entity))
         {
             shell.WriteError(Loc.GetString("cmd-dump_event_tables-error-entity"));
             return;
@@ -27,7 +29,7 @@ internal sealed class DumpEventTablesCommand : LocalizedCommands
 
         var eventBus = (EntityEventBus)_entities.EventBus;
 
-        var table = eventBus._entEventTables[entity];
+        var table = eventBus._entEventTables[entity.Value];
         foreach (var (evType, comps) in table.EventIndices)
         {
             shell.WriteLine($"{evType}:");

Robust.Shared/Console/Commands/MapCommands.cs

@@ -68,6 +68,7 @@ sealed class RemoveMapCommand : LocalizedCommands
 
 sealed class RemoveGridCommand : LocalizedCommands
 {
+    [Dependency] private readonly IEntityManager _entManager = default!;
     [Dependency] private readonly IMapManager _map = default!;
 
     public override string Command => "rmgrid";
@@ -81,15 +82,15 @@ sealed class RemoveGridCommand : LocalizedCommands
             return;
         }
 
-        var gridId = EntityUid.Parse(args[0]);
+        var gridIdNet = NetEntity.Parse(args[0]);
 
-        if (!_map.GridExists(gridId))
+        if (!_entManager.TryGetEntity(gridIdNet, out var gridId) || !_map.GridExists(gridId))
         {
             shell.WriteError($"Grid {gridId} does not exist.");
             return;
         }
 
-        _map.DeleteGrid(gridId);
+        _map.DeleteGrid(gridId.Value);
         shell.WriteLine($"Grid {gridId} was removed.");
     }
 }

Robust.Shared/Console/Commands/SpawnCommand.cs

@@ -32,8 +32,8 @@ public sealed class SpawnCommand : LocalizedCommands
         }
         else if (args.Length == 2)
         {
-            var uid = EntityUid.Parse(args[1]);
-            var entityCoordinates = _entityManager.GetComponent<TransformComponent>(uid).Coordinates;
+            var uidNet = NetEntity.Parse(args[1]);
+            var entityCoordinates = _entityManager.GetComponent<TransformComponent>(_entityManager.GetEntity(uidNet)).Coordinates;
             var createdEntity = _entityManager.SpawnEntity(args[0], entityCoordinates);
             placementEv = new PlacementEntityEvent(createdEntity, entityCoordinates, PlacementEventAction.Create, shell.Player?.UserId);
         }

Robust.Shared/Console/Commands/TeleportCommands.cs

@@ -125,7 +125,7 @@ public sealed class TeleportToCommand : LocalizedCommands
         [NotNullWhen(true)] out EntityUid? victimUid,
         [NotNullWhen(true)] out TransformComponent? transform)
     {
-        if (EntityUid.TryParse(str, out var uid) && _entities.TryGetComponent(uid, out transform))
+        if (NetEntity.TryParse(str, out var uidNet) && _entities.TryGetEntity(uidNet, out var uid) && _entities.TryGetComponent(uid, out transform))
         {
             victimUid = uid;
             return true;
@@ -160,10 +160,10 @@ public sealed class TeleportToCommand : LocalizedCommands
         hint = Loc.GetString(hint);
 
         var opts = CompletionResult.FromHintOptions(users, hint);
-        if (last != string.Empty && !EntityUid.TryParse(last, out _))
+        if (last != string.Empty && !NetEntity.TryParse(last, out _))
             return opts;
 
-        return CompletionResult.FromHintOptions(opts.Options.Concat(CompletionHelper.EntityUids(last, _entities)), hint);
+        return CompletionResult.FromHintOptions(opts.Options.Concat(CompletionHelper.NetEntities(last, _entities)), hint);
     }
 }
 
@@ -201,11 +201,11 @@ sealed class TpGridCommand : LocalizedCommands
             return;
         }
 
-        var gridId = EntityUid.Parse(args[0]);
+        var gridIdNet = NetEntity.Parse(args[0]);
         var xPos = float.Parse(args[1], CultureInfo.InvariantCulture);
         var yPos = float.Parse(args[2], CultureInfo.InvariantCulture);
 
-        if (!_ent.EntityExists(gridId))
+        if (!_ent.TryGetEntity(gridIdNet, out var gridId) || !_ent.EntityExists(gridId))
         {
             shell.WriteError($"Entity does not exist: {args[0]}");
             return;
@@ -217,7 +217,7 @@ sealed class TpGridCommand : LocalizedCommands
             return;
         }
 
-        var gridXform = _ent.GetComponent<TransformComponent>(gridId);
+        var gridXform = _ent.GetComponent<TransformComponent>(gridId.Value);
         var mapId = args.Length == 4 ? new MapId(int.Parse(args[3])) : gridXform.MapID;
 
         gridXform.Coordinates = new EntityCoordinates(_map.GetMapEntityId(mapId), new Vector2(xPos, yPos));

Robust.Shared/Console/CompletionHelper.cs

@@ -155,18 +155,21 @@ public static class CompletionHelper
         }
     }
 
-    public static IEnumerable<CompletionOption> EntityUids(string text, IEntityManager? entManager = null)
+    public static IEnumerable<CompletionOption> NetEntities(string text, IEntityManager? entManager = null)
     {
         IoCManager.Resolve(ref entManager);
 
         foreach (var ent in entManager.GetEntities())
         {
-            var entString = ent.ToString();
-
-            if (!entString.StartsWith(text))
+            if (!entManager.TryGetNetEntity(ent, out var netEntity))
                 continue;
 
-            yield return new CompletionOption(entString);
+            var netString = netEntity.Value.ToString();
+
+            if (!netString.StartsWith(text))
+                continue;
+
+            yield return new CompletionOption(netString);
         }
     }
 
@@ -174,14 +177,19 @@ public static class CompletionHelper
     {
         IoCManager.Resolve(ref entManager);
 
-        var query = entManager.AllEntityQueryEnumerator<T>();
+        var query = entManager.AllEntityQueryEnumerator<T, MetaDataComponent>();
 
-        while (query.MoveNext(out var uid, out _))
+        while (query.MoveNext(out var uid, out _, out var metadata))
         {
-            if (!uid.ToString().StartsWith(text))
+            if (!entManager.TryGetNetEntity(uid, out var netEntity, metadata: metadata))
                 continue;
 
-            yield return new CompletionOption(uid.ToString());
+            var netString = netEntity.Value.ToString();
+
+            if (!netString.StartsWith(text))
+                continue;
+
+            yield return new CompletionOption(netString);
         }
     }
 }

Robust.Shared/Containers/BaseContainer.cs

@@ -12,57 +12,85 @@ using Robust.Shared.ViewVariables;
 using System;
 using System.Collections.Generic;
 using System.Numerics;
-using Robust.Shared.Map.Components;
+using Robust.Shared.Serialization;
 
 namespace Robust.Shared.Containers
 {
     /// <summary>
     /// Base container class that all container inherit from.
     /// </summary>
-    public abstract partial class BaseContainer : IContainer
+    [ImplicitDataDefinitionForInheritors]
+    public abstract partial class BaseContainer
     {
-        /// <inheritdoc />
+        /// <summary>
+        /// Readonly collection of all the entities contained within this specific container
+        /// </summary>
         [ViewVariables]
         public abstract IReadOnlyList<EntityUid> ContainedEntities { get; }
 
-        [ViewVariables]
-        public abstract List<EntityUid> ExpectedEntities { get; }
+        /// <summary>
+        /// Number of contained entities.
+        /// </summary>
+        public abstract int Count { get; }
 
-        /// <inheritdoc />
-        public abstract string ContainerType { get; }
+        [ViewVariables, NonSerialized]
+        public List<NetEntity> ExpectedEntities = new();
 
-        /// <inheritdoc />
-        [ViewVariables]
-        public bool Deleted { get; private set; }
+        /// <summary>
+        /// The ID of this container.
+        /// </summary>
+        [ViewVariables, NonSerialized, Access(typeof(SharedContainerSystem), typeof(ContainerManagerComponent))]
+        public string ID = default!;
 
-        /// <inheritdoc />
-        [ViewVariables]
-        public string ID { get; internal set; } = default!; // Make sure you set me in init
+        [NonSerialized]
+        internal ContainerManagerComponent Manager = default!;
 
-        /// <inheritdoc />
-        public ContainerManagerComponent Manager { get; internal set; } = default!; // Make sure you set me in init
-
-        /// <inheritdoc />
+        /// <summary>
+        /// Prevents light from escaping the container, from ex. a flashlight.
+        /// </summary>
         [ViewVariables(VVAccess.ReadWrite)]
         [DataField("occludes")]
         public bool OccludesLight { get; set; } = true;
 
-        /// <inheritdoc />
+        /// <summary>
+        /// The entity that owns this container.
+        /// </summary>
         [ViewVariables]
         public EntityUid Owner => Manager.Owner;
 
-        /// <inheritdoc />
+        /// <summary>
+        /// Should the contents of this container be shown? False for closed containers like lockers, true for
+        /// things like glass display cases.
+        /// </summary>
         [ViewVariables(VVAccess.ReadWrite)]
         [DataField("showEnts")]
         public bool ShowContents { get; set; }
 
-        /// <summary>
-        /// DO NOT CALL THIS METHOD DIRECTLY!
-        /// You want <see cref="IContainerManager.MakeContainer{T}(string)" /> instead.
-        /// </summary>
-        protected BaseContainer() { }
+        internal void Init(string id, EntityUid owner, ContainerManagerComponent component)
+        {
+            DebugTools.AssertNull(ID);
+            ID = id;
+            Manager = component;
 
-        /// <inheritdoc />
+            // TODO fix container init.
+            // Eventually, we want an owner field, but currently it needs to use component.Owner
+            // Owner = owner;
+        }
+
+        /// <summary>
+        /// Attempts to insert the entity into this container.
+        /// </summary>
+        /// <remarks>
+        /// If the insertion is successful, the inserted entity will end up parented to the
+        /// container entity, and the inserted entity's local position will be set to the zero vector.
+        /// </remarks>
+        /// <param name="toinsert">The entity to insert.</param>
+        /// <param name="entMan"></param>
+        /// <returns>False if the entity could not be inserted.</returns>
+        /// <exception cref="InvalidOperationException">
+        /// Thrown if this container is a child of the entity,
+        /// which would cause infinite loops.
+        /// </exception>
         public bool Insert(
             EntityUid toinsert,
             IEntityManager? entMan = null,
@@ -72,17 +100,12 @@ namespace Robust.Shared.Containers
             PhysicsComponent? physics = null,
             bool force = false)
         {
-            DebugTools.Assert(!Deleted);
+            IoCManager.Resolve(ref entMan);
             DebugTools.Assert(transform == null || transform.Owner == toinsert);
             DebugTools.Assert(ownerTransform == null || ownerTransform.Owner == Owner);
             DebugTools.Assert(ownerTransform == null || ownerTransform.Owner == Owner);
             DebugTools.Assert(physics == null || physics.Owner == toinsert);
-            DebugTools.Assert(!ExpectedEntities.Contains(toinsert));
-            IoCManager.Resolve(ref entMan);
-
-            //Verify we can insert into this container
-            if (!force && !CanInsert(toinsert, entMan))
-                return false;
+            DebugTools.Assert(!ExpectedEntities.Contains(entMan.GetNetEntity(toinsert)));
 
             var physicsQuery = entMan.GetEntityQuery<PhysicsComponent>();
             var transformQuery = entMan.GetEntityQuery<TransformComponent>();
@@ -91,6 +114,11 @@ namespace Robust.Shared.Containers
             // ECS containers when
             var physicsSys = entMan.EntitySysManager.GetEntitySystem<SharedPhysicsSystem>();
             var jointSys = entMan.EntitySysManager.GetEntitySystem<SharedJointSystem>();
+            var containerSys = entMan.EntitySysManager.GetEntitySystem<SharedContainerSystem>();
+
+            //Verify we can insert into this container
+            if (!force && !containerSys.CanInsert(toinsert, this))
+                return false;
 
             // Please somebody ecs containers
             var lookupSys = entMan.EntitySysManager.GetEntitySystem<EntityLookupSystem>();
@@ -214,45 +242,22 @@ namespace Robust.Shared.Containers
             }
         }
 
-        /// <inheritdoc />
-        public virtual bool CanInsert(EntityUid toinsert, IEntityManager? entMan = null)
-        {
-            DebugTools.Assert(!Deleted);
+        /// <summary>
+        /// Whether the given entity can be inserted into this container.
+        /// </summary>
+        /// <param name="assumeEmpty">Whether to assume that the container is currently empty.</param>
+        protected internal virtual bool CanInsert(EntityUid toInsert, bool assumeEmpty, IEntityManager entMan) => true;
 
-            // cannot insert into itself.
-            if (Owner == toinsert)
-                return false;
-
-            IoCManager.Resolve(ref entMan);
-
-            // no, you can't put maps or grids into containers
-            if (entMan.HasComponent<MapComponent>(toinsert) || entMan.HasComponent<MapGridComponent>(toinsert))
-                return false;
-
-            var xformSystem = entMan.EntitySysManager.GetEntitySystem<SharedTransformSystem>();
-            var xformQuery = entMan.GetEntityQuery<TransformComponent>();
-
-            // Crucial, prevent circular insertion.
-            if (xformSystem.ContainsEntity(xformQuery.GetComponent(toinsert), Owner, xformQuery))
-                return false;
-
-            //Improvement: Traverse the entire tree to make sure we are not creating a loop.
-
-            //raise events
-            var insertAttemptEvent = new ContainerIsInsertingAttemptEvent(this, toinsert);
-            entMan.EventBus.RaiseLocalEvent(Owner, insertAttemptEvent, true);
-            if (insertAttemptEvent.Cancelled)
-                return false;
-
-            var gettingInsertedAttemptEvent = new ContainerGettingInsertedAttemptEvent(this, toinsert);
-            entMan.EventBus.RaiseLocalEvent(toinsert, gettingInsertedAttemptEvent, true);
-            if (gettingInsertedAttemptEvent.Cancelled)
-                return false;
-
-            return true;
-        }
-
-        /// <inheritdoc />
+        /// <summary>
+        /// Attempts to remove the entity from this container.
+        /// </summary>
+        /// <param name="reparent">If false, this operation will not rigger a move or parent change event. Ignored if
+        /// destination is not null</param>
+        /// <param name="force">If true, this will not perform can-remove checks.</param>
+        /// <param name="destination">Where to place the entity after removing. Avoids unnecessary broadphase updates.
+        /// If not specified, and reparent option is true, then the entity will either be inserted into a parent
+        /// container, the grid, or the map.</param>
+        /// <param name="localRotation">Optional final local rotation after removal. Avoids redundant move events.</param>
         public bool Remove(
             EntityUid toRemove,
             IEntityManager? entMan = null,
@@ -264,7 +269,6 @@ namespace Robust.Shared.Containers
             Angle? localRotation = null)
         {
             IoCManager.Resolve(ref entMan);
-            DebugTools.Assert(!Deleted);
             DebugTools.AssertNotNull(Manager);
             DebugTools.Assert(entMan.EntityExists(toRemove));
             DebugTools.Assert(xform == null || xform.Owner == toRemove);
@@ -273,7 +277,8 @@ namespace Robust.Shared.Containers
             xform ??= entMan.GetComponent<TransformComponent>(toRemove);
             meta ??= entMan.GetComponent<MetaDataComponent>(toRemove);
 
-            if (!force && !CanRemove(toRemove, entMan))
+            var sys = entMan.EntitySysManager.GetEntitySystem<SharedContainerSystem>();
+            if (!force && !sys.CanRemove(toRemove, this))
                 return false;
 
             if (force && !Contains(toRemove))
@@ -305,7 +310,7 @@ namespace Robust.Shared.Containers
             else if (reparent)
             {
                 // Container ECS when.
-                entMan.EntitySysManager.GetEntitySystem<SharedContainerSystem>().AttachParentToContainerOrGrid(xform);
+                sys.AttachParentToContainerOrGrid(xform);
                 if (localRotation != null)
                     entMan.EntitySysManager.GetEntitySystem<SharedTransformSystem>().SetLocalRotation(xform, localRotation.Value);
             }
@@ -336,40 +341,22 @@ namespace Robust.Shared.Containers
         public void ForceRemove(EntityUid toRemove, IEntityManager? entMan = null, MetaDataComponent? meta = null)
             => Remove(toRemove, entMan, meta: meta, reparent: false, force: true);
 
-        /// <inheritdoc />
-        public virtual bool CanRemove(EntityUid toRemove, IEntityManager? entMan = null)
-        {
-            DebugTools.Assert(!Deleted);
-
-            if (!Contains(toRemove))
-                return false;
-
-            IoCManager.Resolve(ref entMan);
-
-            //raise events
-            var removeAttemptEvent = new ContainerIsRemovingAttemptEvent(this, toRemove);
-            entMan.EventBus.RaiseLocalEvent(Owner, removeAttemptEvent, true);
-            if (removeAttemptEvent.Cancelled)
-                return false;
-
-            var gettingRemovedAttemptEvent = new ContainerGettingRemovedAttemptEvent(this, toRemove);
-            entMan.EventBus.RaiseLocalEvent(toRemove, gettingRemovedAttemptEvent, true);
-            if (gettingRemovedAttemptEvent.Cancelled)
-                return false;
-
-            return true;
-        }
-
-        /// <inheritdoc />
+        /// <summary>
+        /// Checks if the entity is contained in this container.
+        /// This is not recursive, so containers of children are not checked.
+        /// </summary>
+        /// <param name="contained">The entity to check.</param>
+        /// <returns>True if the entity is immediately contained in this container, false otherwise.</returns>
         public abstract bool Contains(EntityUid contained);
 
-        /// <inheritdoc />
+        /// <summary>
+        /// Clears the container and marks it as deleted.
+        /// </summary>
         public void Shutdown(IEntityManager? entMan = null, INetManager? netMan = null)
         {
             IoCManager.Resolve(ref entMan, ref netMan);
             InternalShutdown(entMan, netMan.IsClient);
             Manager.Containers.Remove(ID);
-            Deleted = true;
         }
 
         /// <inheritdoc />

Robust.Shared/Containers/Container.cs

@@ -1,9 +1,11 @@
+using System;
 using System.Collections.Generic;
 using JetBrains.Annotations;
 using Robust.Shared.GameObjects;
 using Robust.Shared.IoC;
 using Robust.Shared.Serialization;
 using Robust.Shared.Serialization.Manager.Attributes;
+using Robust.Shared.Timing;
 using Robust.Shared.Utility;
 
 namespace Robust.Shared.Containers
@@ -15,27 +17,21 @@ namespace Robust.Shared.Containers
     /// For example, inventory containers should be modified only through an inventory component.
     /// </summary>
     [UsedImplicitly]
-    [SerializedType(ClassName)]
+    [SerializedType(nameof(Container))]
     public sealed partial class Container : BaseContainer
     {
-        private const string ClassName = "Container";
-
         /// <summary>
         /// The generic container class uses a list of entities
         /// </summary>
         [DataField("ents")]
+        [NonSerialized]
         private List<EntityUid> _containerList = new();
 
-        private readonly List<EntityUid> _expectedEntities = new();
+        public override int Count => _containerList.Count;
 
         /// <inheritdoc />
         public override IReadOnlyList<EntityUid> ContainedEntities => _containerList;
 
-        public override List<EntityUid> ExpectedEntities => _expectedEntities;
-
-        /// <inheritdoc />
-        public override string ContainerType => ClassName;
-
         /// <inheritdoc />
         protected override void InternalInsert(EntityUid toInsert, IEntityManager entMan)
         {
@@ -56,6 +52,9 @@ namespace Robust.Shared.Containers
                 return false;
 
 #if DEBUG
+            if (IoCManager.Resolve<IGameTiming>().ApplyingState)
+                return true;
+
             var entMan = IoCManager.Resolve<IEntityManager>();
             var flags = entMan.GetComponent<MetaDataComponent>(contained).Flags;
             DebugTools.Assert((flags & MetaDataFlags.InContainer) != 0, $"Entity has bad container flags. Ent: {entMan.ToPrettyString(contained)}. Container: {ID}, Owner: {entMan.ToPrettyString(Owner)}");

Robust.Shared/Containers/ContainerHelpers.cs

@@ -54,7 +54,7 @@ namespace Robust.Shared.Containers
         /// <param name="container">The container that this entity is inside of.</param>
         /// <returns>If a container was found.</returns>
         [Obsolete("Use ContainerSystem.TryGetContainingContainer() instead")]
-        public static bool TryGetContainer(this EntityUid entity, [NotNullWhen(true)] out IContainer? container, IEntityManager? entMan = null)
+        public static bool TryGetContainer(this EntityUid entity, [NotNullWhen(true)] out BaseContainer? container, IEntityManager? entMan = null)
         {
             IoCManager.Resolve(ref entMan);
             DebugTools.Assert(entMan.EntityExists(entity));
@@ -100,7 +100,7 @@ namespace Robust.Shared.Containers
         /// <see cref="SharedContainerSystem.EmptyContainer"/>
         /// </summary>
         [Obsolete("Use SharedContainerSystem.EmptyContainer() instead")]
-        public static void EmptyContainer(this IContainer container, bool force = false, EntityCoordinates? moveTo = null,
+        public static void EmptyContainer(this BaseContainer container, bool force = false, EntityCoordinates? moveTo = null,
             bool attachToGridOrMap = false, IEntityManager? entMan = null)
         {
             IoCManager.Resolve<IEntitySystemManager>().GetEntitySystem<SharedContainerSystem>()
@@ -112,7 +112,7 @@ namespace Robust.Shared.Containers
         /// <see cref="SharedContainerSystem.CleanContainer"/>
         /// </summary>
         [Obsolete("Use SharedContainerSystem.CleanContainer() instead")]
-        public static void CleanContainer(this IContainer container, IEntityManager? entMan = null)
+        public static void CleanContainer(this BaseContainer container, IEntityManager? entMan = null)
         {
             IoCManager.Resolve<IEntitySystemManager>().GetEntitySystem<SharedContainerSystem>()
                 .CleanContainer(container);
@@ -147,10 +147,10 @@ namespace Robust.Shared.Containers
         /// <param name="containerId"></param>
         /// <returns>The new container.</returns>
         /// <exception cref="ArgumentException">Thrown if there already is a container with the specified ID.</exception>
-        /// <seealso cref="IContainerManager.MakeContainer{T}(string)" />
+        /// <seealso cref="BaseContainerManager.MakeContainer{T}(string)" />
         [Obsolete("Use ContainerSystem.MakeContainer() instead")]
         public static T CreateContainer<T>(this EntityUid entity, string containerId, IEntityManager? entMan = null)
-            where T : IContainer
+            where T : BaseContainer
         {
             IoCManager.Resolve(ref entMan);
             var containermanager = entMan.EnsureComponent<ContainerManagerComponent>(entity);
@@ -159,7 +159,7 @@ namespace Robust.Shared.Containers
 
         [Obsolete("Use ContainerSystem.EnsureContainer() instead")]
         public static T EnsureContainer<T>(this EntityUid entity, string containerId, IEntityManager? entMan = null)
-            where T : IContainer
+            where T : BaseContainer
         {
             IoCManager.Resolve(ref entMan);
             return EnsureContainer<T>(entity, containerId, out _, entMan);
@@ -167,7 +167,7 @@ namespace Robust.Shared.Containers
 
         [Obsolete("Use ContainerSystem.EnsureContainer() instead")]
         public static T EnsureContainer<T>(this EntityUid entity, string containerId, out bool alreadyExisted, IEntityManager? entMan = null)
-            where T : IContainer
+            where T : BaseContainer
         {
             IoCManager.Resolve(ref entMan);
             var containerManager = entMan.EnsureComponent<ContainerManagerComponent>(entity);

Robust.Shared/Containers/ContainerManagerComponent.cs

@@ -25,18 +25,16 @@ namespace Robust.Shared.Containers
         [Dependency] private readonly INetManager _netMan = default!;
 
         [DataField("containers")]
-        public Dictionary<string, IContainer> Containers = new();
+        public Dictionary<string, BaseContainer> Containers = new();
 
         void ISerializationHooks.AfterDeserialization()
         {
-            // TODO remove ISerializationHooks I guess the IDs can be set by a custom serializer for the dictionary? But
-            // the component??? Maybe other systems need to stop assuming that containers have been initialized during
-            // their own init.
+            // TODO custom type serializer
+            // TODO set owner uid on init.
             foreach (var (id, container) in Containers)
             {
-                var baseContainer = (BaseContainer) container;
-                baseContainer.Manager = this;
-                baseContainer.ID = id;
+                container.Manager = this;
+                container.ID = id;
             }
         }
 
@@ -55,13 +53,20 @@ namespace Robust.Shared.Containers
 
         /// <inheritdoc />
         public T MakeContainer<T>(string id)
-            where T : IContainer
+            where T : BaseContainer
         {
-            return (T) MakeContainer(id, typeof(T));
+            if (HasContainer(id))
+                throw new ArgumentException($"Container with specified ID already exists: '{id}'");
+
+            var container = _dynFactory.CreateInstanceUnchecked<T>(typeof(T), inject: false);
+            container.Init(id, Owner, this);
+            Containers[id] = container;
+            _entMan.Dirty(this);
+            return container;
         }
 
         /// <inheritdoc />
-        public IContainer GetContainer(string id)
+        public BaseContainer GetContainer(string id)
         {
             return Containers[id];
         }
@@ -73,7 +78,7 @@ namespace Robust.Shared.Containers
         }
 
         /// <inheritdoc />
-        public bool TryGetContainer(string id, [NotNullWhen(true)] out IContainer? container)
+        public bool TryGetContainer(string id, [NotNullWhen(true)] out BaseContainer? container)
         {
             var ret = Containers.TryGetValue(id, out var cont);
             container = cont!;
@@ -81,11 +86,11 @@ namespace Robust.Shared.Containers
         }
 
         /// <inheritdoc />
-        public bool TryGetContainer(EntityUid entity, [NotNullWhen(true)] out IContainer? container)
+        public bool TryGetContainer(EntityUid entity, [NotNullWhen(true)] out BaseContainer? container)
         {
             foreach (var contain in Containers.Values)
             {
-                if (!contain.Deleted && contain.Contains(entity))
+                if (contain.Contains(entity))
                 {
                     container = contain;
                     return true;
@@ -101,7 +106,7 @@ namespace Robust.Shared.Containers
         {
             foreach (var container in Containers.Values)
             {
-                if (!container.Deleted && container.Contains(entity)) return true;
+                if (container.Contains(entity)) return true;
             }
 
             return false;
@@ -125,19 +130,6 @@ namespace Robust.Shared.Containers
             return true; // If we don't contain the entity, it will always be removed
         }
 
-        private IContainer MakeContainer(string id, Type type)
-        {
-            if (HasContainer(id)) throw new ArgumentException($"Container with specified ID already exists: '{id}'");
-
-            var container = _dynFactory.CreateInstanceUnchecked<BaseContainer>(type);
-            container.ID = id;
-            container.Manager = this;
-
-            Containers[id] = container;
-            _entMan.Dirty(this);
-            return container;
-        }
-
         public AllContainersEnumerable GetAllContainers()
         {
             return new(this);
@@ -156,25 +148,22 @@ namespace Robust.Shared.Containers
             [Serializable, NetSerializable]
             public readonly struct ContainerData
             {
-                public readonly string ContainerType;
-                public readonly string Id;
+                public readonly string ContainerType; // TODO remove this. We dont have to send a whole string.
                 public readonly bool ShowContents;
                 public readonly bool OccludesLight;
-                public readonly EntityUid[] ContainedEntities;
+                public readonly NetEntity[] ContainedEntities;
 
-                public ContainerData(string containerType, string id, bool showContents, bool occludesLight, EntityUid[] containedEntities)
+                public ContainerData(string containerType, bool showContents, bool occludesLight, NetEntity[] containedEntities)
                 {
                     ContainerType = containerType;
-                    Id = id;
                     ShowContents = showContents;
                     OccludesLight = occludesLight;
                     ContainedEntities = containedEntities;
                 }
 
-                public void Deconstruct(out string type, out string id, out bool showEnts, out bool occludesLight, out EntityUid[] ents)
+                public void Deconstruct(out string type, out bool showEnts, out bool occludesLight, out NetEntity[] ents)
                 {
                     type = ContainerType;
-                    id = Id;
                     showEnts = ShowContents;
                     occludesLight = OccludesLight;
                     ents = ContainedEntities;
@@ -182,24 +171,7 @@ namespace Robust.Shared.Containers
             }
         }
 
-        [DataDefinition]
-        private partial struct ContainerPrototypeData
-        {
-            [DataField("entities")] public List<EntityUid> Entities = new ();
-
-            [DataField("type")] public string? Type = null;
-
-            // explicit parameterless constructor is required.
-            public ContainerPrototypeData() { }
-
-            public ContainerPrototypeData(List<EntityUid> entities, string type)
-            {
-                Entities = entities;
-                Type = type;
-            }
-        }
-
-        public readonly struct AllContainersEnumerable : IEnumerable<IContainer>
+        public readonly struct AllContainersEnumerable : IEnumerable<BaseContainer>
         {
             private readonly ContainerManagerComponent? _manager;
 
@@ -213,7 +185,7 @@ namespace Robust.Shared.Containers
                 return new(_manager);
             }
 
-            IEnumerator<IContainer> IEnumerable<IContainer>.GetEnumerator()
+            IEnumerator<BaseContainer> IEnumerable<BaseContainer>.GetEnumerator()
             {
                 return GetEnumerator();
             }
@@ -224,9 +196,9 @@ namespace Robust.Shared.Containers
             }
         }
 
-        public struct AllContainersEnumerator : IEnumerator<IContainer>
+        public struct AllContainersEnumerator : IEnumerator<BaseContainer>
         {
-            private Dictionary<string, IContainer>.ValueCollection.Enumerator _enumerator;
+            private Dictionary<string, BaseContainer>.ValueCollection.Enumerator _enumerator;
 
             public AllContainersEnumerator(ContainerManagerComponent? manager)
             {
@@ -238,11 +210,8 @@ namespace Robust.Shared.Containers
             {
                 while (_enumerator.MoveNext())
                 {
-                    if (!_enumerator.Current.Deleted)
-                    {
-                        Current = _enumerator.Current;
-                        return true;
-                    }
+                    Current = _enumerator.Current;
+                    return true;
                 }
 
                 return false;
@@ -250,11 +219,11 @@ namespace Robust.Shared.Containers
 
             void IEnumerator.Reset()
             {
-                ((IEnumerator<IContainer>) _enumerator).Reset();
+                ((IEnumerator<BaseContainer>) _enumerator).Reset();
             }
 
             [AllowNull]
-            public IContainer Current { get; private set; }
+            public BaseContainer Current { get; private set; }
 
             object IEnumerator.Current => Current;
 

Robust.Shared/Containers/ContainerSlot.cs

@@ -6,24 +6,27 @@ using Robust.Shared.IoC;
 using Robust.Shared.Log;
 using Robust.Shared.Serialization;
 using Robust.Shared.Serialization.Manager.Attributes;
+using Robust.Shared.Timing;
 using Robust.Shared.Utility;
 
 namespace Robust.Shared.Containers
 {
     [UsedImplicitly]
-    [SerializedType(ClassName)]
+    [SerializedType(nameof(ContainerSlot))]
     public sealed partial class ContainerSlot : BaseContainer
     {
-        private const string ClassName = "ContainerSlot";
+        public override int Count => ContainedEntity == null ? 0 : 1;
 
         /// <inheritdoc />
         public override IReadOnlyList<EntityUid> ContainedEntities
         {
             get
             {
-                if (ContainedEntity == null)
+                if (_containedEntity == null)
                     return Array.Empty<EntityUid>();
 
+                _containedEntityArray ??= new[] { _containedEntity.Value };
+                DebugTools.Assert(_containedEntityArray[0] == _containedEntity);
                 return _containedEntityArray;
             }
         }
@@ -36,39 +39,19 @@ namespace Robust.Shared.Containers
             {
                 _containedEntity = value;
                 if (value != null)
-                    _containedEntityArray[0] = value!.Value;
+                {
+                    _containedEntityArray ??= new EntityUid[1];
+                    _containedEntityArray[0] = value.Value;
+                }
             }
         }
 
-        public override List<EntityUid> ExpectedEntities => _expectedEntities;
-
+        [NonSerialized]
         private EntityUid? _containedEntity;
-        private readonly List<EntityUid> _expectedEntities = new();
+
         // Used by ContainedEntities to avoid allocating.
-        private readonly EntityUid[] _containedEntityArray = new EntityUid[1];
-
-        /// <inheritdoc />
-        public override string ContainerType => ClassName;
-
-        /// <inheritdoc />
-        public override bool CanInsert(EntityUid toinsert, IEntityManager? entMan = null)
-        {
-            return (ContainedEntity == null) && CanInsertIfEmpty(toinsert, entMan);
-        }
-
-        /// <summary>
-        /// Checks if the entity can be inserted into this container, assuming that the container slot is empty.
-        /// </summary>
-        /// <remarks>
-        /// Useful if you need to know whether an item could be inserted into a slot, without having to actually eject
-        /// the currently contained entity first.
-        /// </remarks>
-        /// <param name="toinsert">The entity to attempt to insert.</param>
-        /// <returns>True if the entity could be inserted into an empty slot, false otherwise.</returns>
-        public bool CanInsertIfEmpty(EntityUid toinsert, IEntityManager? entMan = null)
-        {
-            return base.CanInsert(toinsert, entMan);
-        }
+        [NonSerialized]
+        private EntityUid[]? _containedEntityArray;
 
         /// <inheritdoc />
         public override bool Contains(EntityUid contained)
@@ -77,6 +60,9 @@ namespace Robust.Shared.Containers
                 return false;
 
 #if DEBUG
+            if (IoCManager.Resolve<IGameTiming>().ApplyingState)
+                return true;
+
             var entMan = IoCManager.Resolve<IEntityManager>();
             var flags = entMan.GetComponent<MetaDataComponent>(contained).Flags;
             DebugTools.Assert((flags & MetaDataFlags.InContainer) != 0, $"Entity has bad container flags. Ent: {entMan.ToPrettyString(contained)}. Container: {ID}, Owner: {entMan.ToPrettyString(Owner)}");
@@ -84,6 +70,9 @@ namespace Robust.Shared.Containers
             return true;
         }
 
+        protected internal override bool CanInsert(EntityUid toInsert, bool assumeEmpty, IEntityManager entMan)
+            => ContainedEntity == null || assumeEmpty;
+
         /// <inheritdoc />
         protected override void InternalInsert(EntityUid toInsert, IEntityManager entMan)
         {
@@ -91,7 +80,7 @@ namespace Robust.Shared.Containers
 
             #if DEBUG
             // TODO make this a proper debug assert when gun code no longer fudges client-side spawn prediction.
-            if (toInsert.IsClientSide() && !Owner.IsClientSide() && Manager.NetSyncEnabled)
+            if (entMan.IsClientSide(toInsert) && !entMan.IsClientSide(Owner) && Manager.NetSyncEnabled)
                 Logger.Warning("Inserting a client-side entity into a networked container slot. This will block the container slot and may cause issues.");
             #endif
             ContainedEntity = toInsert;

Robust.Shared/Containers/Events/ContainerAttemptEvents.cs

@@ -6,10 +6,10 @@ namespace Robust.Shared.Containers;
 
 public abstract class ContainerAttemptEventBase : CancellableEntityEventArgs
 {
-    public readonly IContainer Container;
+    public readonly BaseContainer Container;
     public readonly EntityUid EntityUid;
 
-    public ContainerAttemptEventBase(IContainer container, EntityUid entityUid)
+    public ContainerAttemptEventBase(BaseContainer container, EntityUid entityUid)
     {
         Container = container;
         EntityUid = entityUid;
@@ -18,28 +18,44 @@ public abstract class ContainerAttemptEventBase : CancellableEntityEventArgs
 
 public sealed class ContainerIsInsertingAttemptEvent : ContainerAttemptEventBase
 {
-    public ContainerIsInsertingAttemptEvent(IContainer container, EntityUid entityUid) : base(container, entityUid)
+    /// <summary>
+    /// If true, this check should assume that the container is currently empty.
+    /// I.e., could the entity be inserted if the container doesn't contain anything else?
+    /// </summary>
+    public bool AssumeEmpty { get; set; }
+    
+    public ContainerIsInsertingAttemptEvent(BaseContainer container, EntityUid entityUid, bool assumeEmpty)
+        : base(container, entityUid)
     {
+        AssumeEmpty = assumeEmpty;
     }
 }
 
 public sealed class ContainerGettingInsertedAttemptEvent : ContainerAttemptEventBase
 {
-    public ContainerGettingInsertedAttemptEvent(IContainer container, EntityUid entityUid) : base(container, entityUid)
+    /// <summary>
+    /// If true, this check should assume that the container is currently empty.
+    /// I.e., could the entity be inserted if the container doesn't contain anything else?
+    /// </summary>
+    public bool AssumeEmpty { get; set; }
+
+    public ContainerGettingInsertedAttemptEvent(BaseContainer container, EntityUid entityUid, bool assumeEmpty)
+        : base(container, entityUid)
     {
+        AssumeEmpty = assumeEmpty;
     }
 }
 
 public sealed class ContainerIsRemovingAttemptEvent : ContainerAttemptEventBase
 {
-    public ContainerIsRemovingAttemptEvent(IContainer container, EntityUid entityUid) : base(container, entityUid)
+    public ContainerIsRemovingAttemptEvent(BaseContainer container, EntityUid entityUid) : base(container, entityUid)
     {
     }
 }
 
 public sealed class ContainerGettingRemovedAttemptEvent : ContainerAttemptEventBase
 {
-    public ContainerGettingRemovedAttemptEvent(IContainer container, EntityUid entityUid) : base(container, entityUid)
+    public ContainerGettingRemovedAttemptEvent(BaseContainer container, EntityUid entityUid) : base(container, entityUid)
     {
     }
 }

Robust.Shared/Containers/Events/ContainerModifiedMessage.cs

@@ -12,14 +12,14 @@ namespace Robust.Shared.Containers
         /// <summary>
         /// The container being acted upon.
         /// </summary>
-        public IContainer Container { get; }
+        public BaseContainer Container { get; }
 
         /// <summary>
         /// The entity that was removed or inserted from/into the container.
         /// </summary>
         public EntityUid Entity { get; }
 
-        protected ContainerModifiedMessage(EntityUid entity, IContainer container)
+        protected ContainerModifiedMessage(EntityUid entity, BaseContainer container)
         {
             Entity = entity;
             Container = container;

Robust.Shared/Containers/Events/EntGotInsertedIntoContainerMessage.cs

@@ -9,5 +9,5 @@ namespace Robust.Shared.Containers;
 [PublicAPI]
 public sealed class EntGotInsertedIntoContainerMessage : ContainerModifiedMessage
 {
-    public EntGotInsertedIntoContainerMessage(EntityUid entity, IContainer container) : base(entity, container) { }
+    public EntGotInsertedIntoContainerMessage(EntityUid entity, BaseContainer container) : base(entity, container) { }
 }

Robust.Shared/Containers/Events/EntInsertedIntoContainerMessage.cs

@@ -11,7 +11,7 @@ namespace Robust.Shared.Containers
     {
         public readonly EntityUid OldParent;
 
-        public EntInsertedIntoContainerMessage(EntityUid entity, EntityUid oldParent, IContainer container) : base(entity, container)
+        public EntInsertedIntoContainerMessage(EntityUid entity, EntityUid oldParent, BaseContainer container) : base(entity, container)
         {
             OldParent = oldParent;
         }

Robust.Shared/Containers/Events/EntRemovedFromContainerMessage.cs

@@ -9,7 +9,7 @@ namespace Robust.Shared.Containers
     [PublicAPI]
     public sealed class EntRemovedFromContainerMessage : ContainerModifiedMessage
     {
-        public EntRemovedFromContainerMessage(EntityUid entity, IContainer container) : base(entity, container) { }
+        public EntRemovedFromContainerMessage(EntityUid entity, BaseContainer container) : base(entity, container) { }
     }
 
     /// <summary>
@@ -18,6 +18,6 @@ namespace Robust.Shared.Containers
     [PublicAPI]
     public sealed class EntGotRemovedFromContainerMessage : ContainerModifiedMessage
     {
-        public EntGotRemovedFromContainerMessage(EntityUid entity, IContainer container) : base(entity, container) { }
+        public EntGotRemovedFromContainerMessage(EntityUid entity, BaseContainer container) : base(entity, container) { }
     }
 }

Robust.Shared/Containers/IContainer.cs

@@ -1,147 +0,0 @@
-using System;
-using System.Collections.Generic;
-using JetBrains.Annotations;
-using Robust.Shared.GameObjects;
-using Robust.Shared.Map;
-using Robust.Shared.Maths;
-using Robust.Shared.Network;
-using Robust.Shared.Physics.Components;
-using Robust.Shared.Serialization.Manager.Attributes;
-
-namespace Robust.Shared.Containers
-{
-    /// <summary>
-    /// A container is a way to "contain" entities inside other entities, in a logical way.
-    /// This is alike BYOND's <c>contents</c> system, except more advanced.
-    /// </summary>
-    /// <remarks>
-    ///     <p>
-    ///     Containers are logical separations of entities contained inside another entity.
-    ///     for example, a crate with two separated compartments would have two separate containers.
-    ///     If an entity inside compartment A drops something,
-    ///     the dropped entity would be placed in compartment A too,
-    ///     and compartment B would be completely untouched.
-    ///     </p>
-    ///     <p>
-    ///     Containers are managed by an entity's <see cref="IContainerManager" />,
-    ///     and have an ID to be referenced by.
-    ///     </p>
-    /// </remarks>
-    /// <seealso cref="IContainerManager" />
-    [PublicAPI]
-    [ImplicitDataDefinitionForInheritors]
-    public partial interface IContainer
-    {
-        /// <summary>
-        /// Readonly collection of all the entities contained within this specific container
-        /// </summary>
-        IReadOnlyList<EntityUid> ContainedEntities { get; }
-
-        List<EntityUid> ExpectedEntities { get; }
-
-        /// <summary>
-        /// The type of this container.
-        /// </summary>
-        string ContainerType { get; }
-
-        /// <summary>
-        /// True if the container has been shut down via <see cref="Shutdown" />
-        /// </summary>
-        bool Deleted { get; }
-
-        /// <summary>
-        /// The ID of this container.
-        /// </summary>
-        string ID { get; }
-
-        /// <summary>
-        /// Prevents light from escaping the container, from ex. a flashlight.
-        /// </summary>
-        bool OccludesLight { get; set; }
-
-        /// <summary>
-        /// The entity owning this container.
-        /// </summary>
-        EntityUid Owner { get; }
-
-        /// <summary>
-        /// Should the contents of this container be shown? False for closed containers like lockers, true for
-        /// things like glass display cases.
-        /// </summary>
-        bool ShowContents { get; set; }
-
-        /// <summary>
-        /// Checks if the entity can be inserted into this container.
-        /// </summary>
-        /// <param name="toinsert">The entity to attempt to insert.</param>
-        /// <param name="entMan"></param>
-        /// <returns>True if the entity can be inserted, false otherwise.</returns>
-        bool CanInsert(EntityUid toinsert, IEntityManager? entMan = null);
-
-        /// <summary>
-        /// Attempts to insert the entity into this container.
-        /// </summary>
-        /// <remarks>
-        /// If the insertion is successful, the inserted entity will end up parented to the
-        /// container entity, and the inserted entity's local position will be set to the zero vector.
-        /// </remarks>
-        /// <param name="toinsert">The entity to insert.</param>
-        /// <param name="entMan"></param>
-        /// <returns>False if the entity could not be inserted.</returns>
-        /// <exception cref="InvalidOperationException">
-        /// Thrown if this container is a child of the entity,
-        /// which would cause infinite loops.
-        /// </exception>
-        bool Insert(EntityUid toinsert,
-            IEntityManager? entMan = null,
-            TransformComponent? transform = null,
-            TransformComponent? ownerTransform = null,
-            MetaDataComponent? meta = null,
-            PhysicsComponent? physics = null,
-            bool force = false);
-
-        /// <summary>
-        /// Checks if the entity can be removed from this container.
-        /// </summary>
-        /// <param name="toremove">The entity to check.</param>
-        /// <param name="entMan"></param>
-        /// <returns>True if the entity can be removed, false otherwise.</returns>
-        bool CanRemove(EntityUid toremove, IEntityManager? entMan = null);
-
-        /// <summary>
-        /// Attempts to remove the entity from this container.
-        /// </summary>
-        /// <param name="reparent">If false, this operation will not rigger a move or parent change event. Ignored if
-        /// destination is not null</param>
-        /// <param name="force">If true, this will not perform can-remove checks.</param>
-        /// <param name="destination">Where to place the entity after removing. Avoids unnecessary broadphase updates.
-        /// If not specified, and reparent option is true, then the entity will either be inserted into a parent
-        /// container, the grid, or the map.</param>
-        /// <param name="localRotation">Optional final local rotation after removal. Avoids redundant move events.</param>
-        bool Remove(
-            EntityUid toremove,
-            IEntityManager? entMan = null,
-            TransformComponent? xform = null,
-            MetaDataComponent? meta = null,
-            bool reparent = true,
-            bool force = false,
-            EntityCoordinates? destination = null,
-            Angle? localRotation = null);
-
-        [Obsolete("use force option in Remove()")]
-        void ForceRemove(EntityUid toRemove, IEntityManager? entMan = null, MetaDataComponent? meta = null);
-
-        /// <summary>
-        /// Checks if the entity is contained in this container.
-        /// This is not recursive, so containers of children are not checked.
-        /// </summary>
-        /// <param name="contained">The entity to check.</param>
-        /// <returns>True if the entity is immediately contained in this container, false otherwise.</returns>
-        bool Contains(EntityUid contained);
-
-        /// <summary>
-        /// Clears the container and marks it as deleted.
-        /// </summary>
-        void Shutdown(IEntityManager? entMan = null, INetManager? netMan = null);
-    }
-}

Robust.Shared/Containers/SharedContainerSystem.Insert.cs

@@ -0,0 +1,49 @@
+using Robust.Shared.GameObjects;
+using Robust.Shared.Utility;
+
+namespace Robust.Shared.Containers;
+
+public abstract partial class SharedContainerSystem
+{
+    /// <summary>
+    /// Checks if the entity can be inserted into the given container.
+    /// </summary>
+    /// <param name="assumeEmpty">If true, this will check whether the entity could be inserted if the container were
+    /// empty.</param>
+    public bool CanInsert(
+        EntityUid toInsert,
+        BaseContainer container,
+        TransformComponent? toInsertXform = null,
+        bool assumeEmpty = false)
+    {
+        if (container.Owner == toInsert)
+            return false;
+
+        if (!assumeEmpty && container.Contains(toInsert))
+            return false;
+
+        if (!container.CanInsert(toInsert, assumeEmpty, EntityManager))
+            return false;
+
+        if (!TransformQuery.Resolve(toInsert, ref toInsertXform))
+            return false;
+
+        // no, you can't put maps or grids into containers
+        if (_mapQuery.HasComponent(toInsert) || _gridQuery.HasComponent(toInsert))
+            return false;
+
+        // Prevent circular insertion.
+        if (_transform.ContainsEntity(toInsertXform, container.Owner))
+            return false;
+
+        var insertAttemptEvent = new ContainerIsInsertingAttemptEvent(container, toInsert, assumeEmpty);
+        RaiseLocalEvent(container.Owner, insertAttemptEvent, true);
+        if (insertAttemptEvent.Cancelled)
+            return false;
+
+        var gettingInsertedAttemptEvent = new ContainerGettingInsertedAttemptEvent(container, toInsert, assumeEmpty);
+        RaiseLocalEvent(toInsert, gettingInsertedAttemptEvent, true);
+
+        return !gettingInsertedAttemptEvent.Cancelled;
+    }
+}

Robust.Shared/Containers/SharedContainerSystem.Remove.cs

@@ -0,0 +1,26 @@
+using Robust.Shared.GameObjects;
+
+namespace Robust.Shared.Containers;
+
+public abstract partial class SharedContainerSystem
+{
+    /// <summary>
+    /// Checks if the entity can be removed from this container.
+    /// </summary>
+    /// <returns>True if the entity can be removed, false otherwise.</returns>
+    public bool CanRemove(EntityUid toRemove, BaseContainer container)
+    {
+        if (!container.Contains(toRemove))
+            return false;
+
+        //raise events
+        var removeAttemptEvent = new ContainerIsRemovingAttemptEvent(container, toRemove);
+        RaiseLocalEvent(container.Owner, removeAttemptEvent, true);
+        if (removeAttemptEvent.Cancelled)
+            return false;
+
+        var gettingRemovedAttemptEvent = new ContainerGettingRemovedAttemptEvent(container, toRemove);
+        RaiseLocalEvent(toRemove, gettingRemovedAttemptEvent, true);
+        return !gettingRemovedAttemptEvent.Cancelled;
+    }
+}

Robust.Shared/Containers/SharedContainerSystem.Validation.cs

@@ -13,22 +13,18 @@ public abstract partial class SharedContainerSystem : EntitySystem
 {
     private void OnStartupValidation(EntityUid uid, ContainerManagerComponent component, ComponentStartup args)
     {
-        var metaQuery = GetEntityQuery<MetaDataComponent>();
-        var xformQuery = GetEntityQuery<TransformComponent>();
-        var physicsQuery = GetEntityQuery<PhysicsComponent>();
-        var jointQuery = GetEntityQuery<JointComponent>();
         foreach (var cont in component.Containers.Values)
         {
             foreach (var ent in cont.ContainedEntities)
             {
-                if (!metaQuery.TryGetComponent(ent, out var meta))
+                if (!MetaQuery.TryGetComponent(ent, out var meta))
                 {
                     ValidateMissingEntity(uid, cont, ent);
                     continue;
                 }
 
-                var xform = xformQuery.GetComponent(ent);
-                physicsQuery.TryGetComponent(ent, out var physics);
+                var xform = TransformQuery.GetComponent(ent);
+                PhysicsQuery.TryGetComponent(ent, out var physics);
 
                 DebugTools.Assert(xform.ParentUid == uid,
                     $"Entity not parented to its container. Entity: {ToPrettyString(ent)}, parent: {ToPrettyString(uid)}");
@@ -46,15 +42,15 @@ public abstract partial class SharedContainerSystem : EntitySystem
                 // entities in containers without having to "re-insert" them.
                 meta.Flags |= MetaDataFlags.InContainer;
                 _lookup.RemoveFromEntityTree(ent, xform);
-                ((BaseContainer)cont).RecursivelyUpdatePhysics(ent, xform, physics, _physics, physicsQuery, xformQuery);
+                cont.RecursivelyUpdatePhysics(ent, xform, physics, _physics, PhysicsQuery, TransformQuery);
 
                 // assert children have correct properties
-                ValidateChildren(xform, xformQuery, physicsQuery);
+                ValidateChildren(xform, TransformQuery, PhysicsQuery);
             }
         }
     }
 
-    protected abstract void ValidateMissingEntity(EntityUid uid, IContainer cont, EntityUid missing);
+    protected abstract void ValidateMissingEntity(EntityUid uid, BaseContainer cont, EntityUid missing);
 
     private void ValidateChildren(TransformComponent xform, EntityQuery<TransformComponent> xformQuery, EntityQuery<PhysicsComponent> physicsQuery)
     {

Robust.Shared/Containers/SharedContainerSystem.cs

@@ -6,7 +6,9 @@ using Robust.Shared.GameObjects;
 using Robust.Shared.GameStates;
 using Robust.Shared.IoC;
 using Robust.Shared.Map;
+using Robust.Shared.Map.Components;
 using Robust.Shared.Maths;
+using Robust.Shared.Physics.Components;
 using Robust.Shared.Physics.Systems;
 using Robust.Shared.Utility;
 
@@ -16,9 +18,13 @@ namespace Robust.Shared.Containers
     {
         [Dependency] private readonly SharedPhysicsSystem _physics = default!;
         [Dependency] private readonly EntityLookupSystem _lookup = default!;
+        [Dependency] private readonly SharedTransformSystem _transform = default!;
 
-        private EntityQuery<MetaDataComponent> _metas;
-        private EntityQuery<TransformComponent> _xforms;
+        private EntityQuery<MapGridComponent> _gridQuery;
+        private EntityQuery<MapComponent> _mapQuery;
+        protected EntityQuery<MetaDataComponent> MetaQuery;
+        protected EntityQuery<PhysicsComponent> PhysicsQuery;
+        protected EntityQuery<TransformComponent> TransformQuery;
 
         /// <inheritdoc />
         public override void Initialize()
@@ -29,25 +35,27 @@ namespace Robust.Shared.Containers
             SubscribeLocalEvent<ContainerManagerComponent, ComponentStartup>(OnStartupValidation);
             SubscribeLocalEvent<ContainerManagerComponent, ComponentGetState>(OnContainerGetState);
 
-            _metas = EntityManager.GetEntityQuery<MetaDataComponent>();
-            _xforms = EntityManager.GetEntityQuery<TransformComponent>();
+            _gridQuery = GetEntityQuery<MapGridComponent>();
+            _mapQuery = GetEntityQuery<MapComponent>();
+            MetaQuery = GetEntityQuery<MetaDataComponent>();
+            PhysicsQuery = GetEntityQuery<PhysicsComponent>();
+            TransformQuery = GetEntityQuery<TransformComponent>();
         }
 
         private void OnContainerGetState(EntityUid uid, ContainerManagerComponent component, ref ComponentGetState args)
         {
-            // naive implementation that just sends the full state of the component
             Dictionary<string, ContainerManagerComponent.ContainerManagerComponentState.ContainerData> containerSet = new(component.Containers.Count);
 
             foreach (var container in component.Containers.Values)
             {
-                var uidArr = new EntityUid[container.ContainedEntities.Count];
+                var uidArr = new NetEntity[container.ContainedEntities.Count];
 
                 for (var index = 0; index < container.ContainedEntities.Count; index++)
                 {
-                    uidArr[index] = container.ContainedEntities[index];
+                    uidArr[index] = GetNetEntity(container.ContainedEntities[index]);
                 }
 
-                var sContainer = new ContainerManagerComponent.ContainerManagerComponentState.ContainerData(container.ContainerType, container.ID, container.ShowContents, container.OccludesLight, uidArr);
+                var sContainer = new ContainerManagerComponent.ContainerManagerComponentState.ContainerData(container.GetType().Name, container.ShowContents, container.OccludesLight, uidArr);
                 containerSet.Add(container.ID, sContainer);
             }
 
@@ -59,7 +67,7 @@ namespace Robust.Shared.Containers
         #region Proxy Methods
 
         public T MakeContainer<T>(EntityUid uid, string id, ContainerManagerComponent? containerManager = null)
-            where T : IContainer
+            where T : BaseContainer
         {
             if (!Resolve(uid, ref containerManager, false))
                 containerManager = EntityManager.AddComponent<ContainerManagerComponent>(uid); // Happy Vera.
@@ -68,7 +76,7 @@ namespace Robust.Shared.Containers
         }
 
         public T EnsureContainer<T>(EntityUid uid, string id, out bool alreadyExisted, ContainerManagerComponent? containerManager = null)
-            where T : IContainer
+            where T : BaseContainer
         {
             if (!Resolve(uid, ref containerManager, false))
                 containerManager = EntityManager.AddComponent<ContainerManagerComponent>(uid);
@@ -88,12 +96,12 @@ namespace Robust.Shared.Containers
         }
 
         public T EnsureContainer<T>(EntityUid uid, string id, ContainerManagerComponent? containerManager = null)
-           where T : IContainer
+           where T : BaseContainer
         {
             return EnsureContainer<T>(uid, id, out _, containerManager);
         }
 
-        public IContainer GetContainer(EntityUid uid, string id, ContainerManagerComponent? containerManager = null)
+        public BaseContainer GetContainer(EntityUid uid, string id, ContainerManagerComponent? containerManager = null)
         {
             if (!Resolve(uid, ref containerManager))
                 throw new ArgumentException("Entity does not have a ContainerManagerComponent!", nameof(uid));
@@ -109,7 +117,7 @@ namespace Robust.Shared.Containers
             return containerManager.HasContainer(id);
         }
 
-        public bool TryGetContainer(EntityUid uid, string id, [NotNullWhen(true)] out IContainer? container, ContainerManagerComponent? containerManager = null)
+        public bool TryGetContainer(EntityUid uid, string id, [NotNullWhen(true)] out BaseContainer? container, ContainerManagerComponent? containerManager = null)
         {
             if (Resolve(uid, ref containerManager, false))
                 return containerManager.TryGetContainer(id, out container);
@@ -118,7 +126,7 @@ namespace Robust.Shared.Containers
             return false;
         }
 
-        public bool TryGetContainingContainer(EntityUid uid, EntityUid containedUid, [NotNullWhen(true)] out IContainer? container, ContainerManagerComponent? containerManager = null, bool skipExistCheck = false)
+        public bool TryGetContainingContainer(EntityUid uid, EntityUid containedUid, [NotNullWhen(true)] out BaseContainer? container, ContainerManagerComponent? containerManager = null, bool skipExistCheck = false)
         {
             if (Resolve(uid, ref containerManager, false) && (skipExistCheck || EntityManager.EntityExists(containedUid)))
                 return containerManager.TryGetContainer(containedUid, out container);
@@ -164,7 +172,7 @@ namespace Robust.Shared.Containers
 
         #region Container Helpers
 
-        public bool TryGetContainingContainer(EntityUid uid, [NotNullWhen(true)] out IContainer? container, MetaDataComponent? meta = null, TransformComponent? transform = null)
+        public bool TryGetContainingContainer(EntityUid uid, [NotNullWhen(true)] out BaseContainer? container, MetaDataComponent? meta = null, TransformComponent? transform = null)
         {
             container = null;
 
@@ -227,7 +235,7 @@ namespace Robust.Shared.Containers
         }
 
         /// <summary>
-        ///     Finds the first instance of a component on the recursive parented containers that hold an entity  
+        ///     Finds the first instance of a component on the recursive parented containers that hold an entity
         /// </summary>
         public bool TryFindComponentOnEntityContainerOrParent<T>(
             EntityUid uid,
@@ -236,13 +244,13 @@ namespace Robust.Shared.Containers
             MetaDataComponent? meta = null,
             TransformComponent? xform = null) where T : Component
         {
-            if (!_metas.Resolve(uid, ref meta))
+            if (!MetaQuery.Resolve(uid, ref meta))
                 return false;
 
             if ((meta.Flags & MetaDataFlags.InContainer) != MetaDataFlags.InContainer)
                 return false;
 
-            if (!_xforms.Resolve(uid, ref xform))
+            if (!TransformQuery.Resolve(uid, ref xform))
                 return false;
 
             if (!xform.ParentUid.Valid)
@@ -255,7 +263,7 @@ namespace Robust.Shared.Containers
         }
 
         /// <summary>
-        ///     Finds all instances of a component on the recursive parented containers that hold an entity  
+        ///     Finds all instances of a component on the recursive parented containers that hold an entity
         /// </summary>
         public bool TryFindComponentsOnEntityContainerOrParent<T>(
             EntityUid uid,
@@ -264,13 +272,13 @@ namespace Robust.Shared.Containers
             MetaDataComponent? meta = null,
             TransformComponent? xform = null) where T : Component
         {
-            if (!_metas.Resolve(uid, ref meta))
+            if (!MetaQuery.Resolve(uid, ref meta))
                 return foundComponents.Any();
 
             if ((meta.Flags & MetaDataFlags.InContainer) != MetaDataFlags.InContainer)
                 return foundComponents.Any();
 
-            if (!_xforms.Resolve(uid, ref xform))
+            if (!TransformQuery.Resolve(uid, ref xform))
                 return foundComponents.Any();
 
             if (!xform.ParentUid.Valid)
@@ -335,8 +343,8 @@ namespace Robust.Shared.Containers
         public bool IsInSameOrTransparentContainer(
             EntityUid user,
             EntityUid other,
-            IContainer? userContainer = null,
-            IContainer? otherContainer = null,
+            BaseContainer? userContainer = null,
+            BaseContainer? otherContainer = null,
             bool userSeeInsideSelf = false)
         {
             if (userContainer == null)
@@ -371,14 +379,14 @@ namespace Robust.Shared.Containers
         /// <summary>
         /// Gets the top-most container in the hierarchy for this entity, if it exists.
         /// </summary>
-        public bool TryGetOuterContainer(EntityUid uid, TransformComponent xform, [NotNullWhen(true)] out IContainer? container)
+        public bool TryGetOuterContainer(EntityUid uid, TransformComponent xform, [NotNullWhen(true)] out BaseContainer? container)
         {
             var xformQuery = EntityManager.GetEntityQuery<TransformComponent>();
             return TryGetOuterContainer(uid, xform, out container, xformQuery);
         }
 
         public bool TryGetOuterContainer(EntityUid uid, TransformComponent xform,
-            [NotNullWhen(true)] out IContainer? container, EntityQuery<TransformComponent> xformQuery)
+            [NotNullWhen(true)] out BaseContainer? container, EntityQuery<TransformComponent> xformQuery)
         {
             container = null;
 
@@ -448,7 +456,7 @@ namespace Robust.Shared.Containers
         /// Attempts to remove all entities in a container. Returns removed entities.
         /// </summary>
         public List<EntityUid> EmptyContainer(
-            IContainer container,
+            BaseContainer container,
             bool force = false,
             EntityCoordinates? destination = null,
             bool reparent = true)
@@ -470,7 +478,7 @@ namespace Robust.Shared.Containers
         /// <summary>
         /// Attempts to remove and delete all entities in a container.
         /// </summary>
-        public void CleanContainer(IContainer container)
+        public void CleanContainer(BaseContainer container)
         {
             foreach (var ent in container.ContainedEntities.ToArray())
             {
@@ -491,7 +499,7 @@ namespace Robust.Shared.Containers
                 transform.AttachToGridOrMap();
         }
 
-        private bool TryInsertIntoContainer(TransformComponent transform, IContainer container)
+        private bool TryInsertIntoContainer(TransformComponent transform, BaseContainer container)
         {
             if (container.Insert(transform.Owner)) return true;
 

Robust.Shared/GameObjects/Components/MetaDataComponent.cs

@@ -63,6 +63,13 @@ namespace Robust.Shared.GameObjects
         [DataField("desc")] internal string? _entityDescription;
         internal EntityPrototype? _entityPrototype;
 
+        /// <summary>
+        /// Network identifier for this entity.
+        /// </summary>
+        [ViewVariables]
+        [Access(typeof(EntityManager), Other = AccessPermissions.ReadExecute)]
+        public NetEntity NetEntity { get; internal set; } = NetEntity.Invalid;
+
         /// <summary>
         /// When this entity was paused, if applicable. Note that this is the actual time, not the duration which gets
         /// returned by <see cref="MetaDataSystem.GetPauseTime"/>.

Robust.Shared/GameObjects/Components/UserInterface/SharedUserInterfaceComponent.cs

@@ -64,21 +64,29 @@ namespace Robust.Shared.GameObjects
     {
     }
 
+    /// <summary>
+    /// Abstract class for local BUI events.
+    /// </summary>
+    public abstract class BaseLocalBoundUserInterfaceEvent : BaseBoundUserInterfaceEvent
+    {
+        /// <summary>
+        ///     The Entity receiving the message.
+        ///     Only set when the message is raised as a directed event.
+        /// </summary>
+        public EntityUid Entity = EntityUid.Invalid;
+    }
 
-    [NetSerializable, Serializable]
-    public abstract class BoundUserInterfaceMessage : EntityEventArgs
+    /// <summary>
+    /// Abstract class for all BUI events.
+    /// </summary>
+    [Serializable, NetSerializable]
+    public abstract class BaseBoundUserInterfaceEvent : EntityEventArgs
     {
         /// <summary>
         ///     The UI of this message.
         ///     Only set when the message is raised as a directed event.
         /// </summary>
-        public Enum UiKey { get; set; } = default!;
-
-        /// <summary>
-        ///     The Entity receiving the message.
-        ///     Only set when the message is raised as a directed event.
-        /// </summary>
-        public EntityUid Entity { get; set; } = EntityUid.Invalid;
+        public Enum UiKey = default!;
 
         /// <summary>
         ///     The session sending or receiving this message.
@@ -88,6 +96,19 @@ namespace Robust.Shared.GameObjects
         public ICommonSession Session = default!;
     }
 
+    /// <summary>
+    /// Abstract class for networked BUI events.
+    /// </summary>
+    [NetSerializable, Serializable]
+    public abstract class BoundUserInterfaceMessage : BaseBoundUserInterfaceEvent
+    {
+        /// <summary>
+        ///     The Entity receiving the message.
+        ///     Only set when the message is raised as a directed event.
+        /// </summary>
+        public NetEntity Entity { get; set; } = NetEntity.Invalid;
+    }
+
     [NetSerializable, Serializable]
     internal sealed class UpdateBoundStateMessage : BoundUserInterfaceMessage
     {
@@ -112,11 +133,11 @@ namespace Robust.Shared.GameObjects
     [Serializable, NetSerializable]
     internal sealed class BoundUIWrapMessage : EntityEventArgs
     {
-        public readonly EntityUid Entity;
+        public readonly NetEntity Entity;
         public readonly BoundUserInterfaceMessage Message;
         public readonly Enum UiKey;
 
-        public BoundUIWrapMessage(EntityUid entity, BoundUserInterfaceMessage message, Enum uiKey)
+        public BoundUIWrapMessage(NetEntity entity, BoundUserInterfaceMessage message, Enum uiKey)
         {
             Message = message;
             UiKey = uiKey;
@@ -129,7 +150,7 @@ namespace Robust.Shared.GameObjects
         }
     }
 
-    public sealed class BoundUIOpenedEvent : BoundUserInterfaceMessage
+    public sealed class BoundUIOpenedEvent : BaseLocalBoundUserInterfaceEvent
     {
         public BoundUIOpenedEvent(Enum uiKey, EntityUid uid, ICommonSession session)
         {
@@ -139,7 +160,7 @@ namespace Robust.Shared.GameObjects
         }
     }
 
-    public sealed class BoundUIClosedEvent : BoundUserInterfaceMessage
+    public sealed class BoundUIClosedEvent : BaseLocalBoundUserInterfaceEvent
     {
         public BoundUIClosedEvent(Enum uiKey, EntityUid uid, ICommonSession session)
         {

Robust.Shared/GameObjects/EntityManager.Components.cs

@@ -1065,7 +1065,7 @@ namespace Robust.Shared.GameObjects
             where TComp1 : Component
         {
             var trait1 = _entTraitArray[CompIdx.ArrayIndex<TComp1>()];
-            return new EntityQueryEnumerator<TComp1>(trait1, _metaQuery);
+            return new EntityQueryEnumerator<TComp1>(trait1, MetaQuery);
         }
 
         public EntityQueryEnumerator<TComp1, TComp2> EntityQueryEnumerator<TComp1, TComp2>()
@@ -1074,7 +1074,7 @@ namespace Robust.Shared.GameObjects
         {
             var trait1 = _entTraitArray[CompIdx.ArrayIndex<TComp1>()];
             var trait2 = _entTraitArray[CompIdx.ArrayIndex<TComp2>()];
-            return new EntityQueryEnumerator<TComp1, TComp2>(trait1, trait2, _metaQuery);
+            return new EntityQueryEnumerator<TComp1, TComp2>(trait1, trait2, MetaQuery);
         }
 
         public EntityQueryEnumerator<TComp1, TComp2, TComp3> EntityQueryEnumerator<TComp1, TComp2, TComp3>()
@@ -1085,7 +1085,7 @@ namespace Robust.Shared.GameObjects
             var trait1 = _entTraitArray[CompIdx.ArrayIndex<TComp1>()];
             var trait2 = _entTraitArray[CompIdx.ArrayIndex<TComp2>()];
             var trait3 = _entTraitArray[CompIdx.ArrayIndex<TComp3>()];
-            return new EntityQueryEnumerator<TComp1, TComp2, TComp3>(trait1, trait2, trait3, _metaQuery);
+            return new EntityQueryEnumerator<TComp1, TComp2, TComp3>(trait1, trait2, trait3, MetaQuery);
         }
 
         public EntityQueryEnumerator<TComp1, TComp2, TComp3, TComp4> EntityQueryEnumerator<TComp1, TComp2, TComp3, TComp4>()
@@ -1099,7 +1099,7 @@ namespace Robust.Shared.GameObjects
             var trait3 = _entTraitArray[CompIdx.ArrayIndex<TComp3>()];
             var trait4 = _entTraitArray[CompIdx.ArrayIndex<TComp4>()];
 
-            return new EntityQueryEnumerator<TComp1, TComp2, TComp3, TComp4>(trait1, trait2, trait3, trait4, _metaQuery);
+            return new EntityQueryEnumerator<TComp1, TComp2, TComp3, TComp4>(trait1, trait2, trait3, trait4, MetaQuery);
         }
 
         /// <inheritdoc />
@@ -1121,7 +1121,7 @@ namespace Robust.Shared.GameObjects
             {
                 foreach (var t1Comp in comps.Values)
                 {
-                    if (t1Comp.Deleted || !_metaQuery.TryGetComponentInternal(t1Comp.Owner, out var metaComp)) continue;
+                    if (t1Comp.Deleted || !MetaQuery.TryGetComponentInternal(t1Comp.Owner, out var metaComp)) continue;
 
                     if (metaComp.EntityPaused) continue;
 
@@ -1312,7 +1312,7 @@ namespace Robust.Shared.GameObjects
             {
                 foreach (var (uid, comp) in comps)
                 {
-                    if (comp.Deleted || !_metaQuery.TryGetComponent(uid, out var meta) || meta.EntityPaused) continue;
+                    if (comp.Deleted || !MetaQuery.TryGetComponent(uid, out var meta) || meta.EntityPaused) continue;
 
                     yield return (uid, comp);
                 }

Robust.Shared/GameObjects/EntityManager.Network.cs

@@ -0,0 +1,585 @@
+using System;
+using System.Collections.Generic;
+using System.Diagnostics.CodeAnalysis;
+using System.Runtime.CompilerServices;
+using Robust.Shared.Map;
+using Robust.Shared.Utility;
+
+namespace Robust.Shared.GameObjects;
+
+public partial class EntityManager
+{
+    // TODO POOLING
+    // Just add overrides that take in an existing collection.
+
+    /// <summary>
+    /// Inverse lookup for net entities.
+    /// Regular lookup uses MetadataComponent.
+    /// </summary>
+    protected readonly Dictionary<NetEntity, EntityUid> NetEntityLookup = new(EntityCapacity);
+
+    /// <summary>
+    /// Clears an old inverse lookup for a particular entityuid.
+    /// Do not call this unless you are sure of what you're doing.
+    /// </summary>
+    internal void ClearNetEntity(NetEntity netEntity)
+    {
+        NetEntityLookup.Remove(netEntity);
+    }
+
+    /// <summary>
+    /// Set the inverse lookup for a particular entityuid.
+    /// Do not call this unless you are sure of what you're doing.
+    /// </summary>
+    internal void SetNetEntity(EntityUid uid, NetEntity netEntity, MetaDataComponent component)
+    {
+        DebugTools.Assert(!NetEntityLookup.ContainsKey(netEntity));
+        NetEntityLookup[netEntity] = uid;
+        component.NetEntity = netEntity;
+    }
+
+    /// <inheritdoc />
+    public virtual bool IsClientSide(EntityUid uid, MetaDataComponent? metadata = null)
+    {
+        return false;
+    }
+
+    #region NetEntity
+
+    /// <inheritdoc />
+    public bool TryParseNetEntity(string arg, [NotNullWhen(true)] out EntityUid? entity)
+    {
+        if (!NetEntity.TryParse(arg, out var netEntity) ||
+            !TryGetEntity(netEntity, out entity))
+        {
+            entity = null;
+            return false;
+        }
+
+        return true;
+    }
+
+    /// <inheritdoc />
+    public bool TryGetEntity(NetEntity nEntity, [NotNullWhen(true)] out EntityUid? entity)
+    {
+        if (NetEntityLookup.TryGetValue(nEntity, out var went))
+        {
+            entity = went;
+            return true;
+        }
+
+        entity = EntityUid.Invalid;
+        return false;
+    }
+
+    /// <inheritdoc />
+    public bool TryGetEntity(NetEntity? nEntity, [NotNullWhen(true)] out EntityUid? entity)
+    {
+        if (nEntity == null)
+        {
+            entity = EntityUid.Invalid;
+            return false;
+        }
+
+        return TryGetEntity(nEntity.Value, out entity);
+    }
+
+    /// <inheritdoc />
+    public bool TryGetNetEntity(EntityUid uid, [NotNullWhen(true)] out NetEntity? netEntity, MetaDataComponent? metadata = null)
+    {
+        if (uid == EntityUid.Invalid)
+        {
+            netEntity = NetEntity.Invalid;
+            return false;
+        }
+
+        // TODO NetEntity figure out why this happens
+        // I wanted this to logMissing but it seems to break a loootttt of dodgy stuff on content.
+        if (MetaQuery.Resolve(uid, ref metadata, false))
+        {
+            netEntity = metadata.NetEntity;
+            return true;
+        }
+
+        netEntity = NetEntity.Invalid;
+        return false;
+    }
+
+    /// <inheritdoc />
+    public bool TryGetNetEntity(EntityUid? uid, [NotNullWhen(true)] out NetEntity? netEntity, MetaDataComponent? metadata = null)
+    {
+        if (uid == null)
+        {
+            netEntity = NetEntity.Invalid;
+            return false;
+        }
+
+        return TryGetNetEntity(uid.Value, out netEntity, metadata);
+    }
+
+    /// <inheritdoc />
+    public virtual EntityUid EnsureEntity<T>(NetEntity nEntity, EntityUid callerEntity)
+    {
+        // On server we don't want to ensure any reserved entities for later or flag for comp state handling
+        // so this is just GetEntity. Client-side code overrides this method.
+        return GetEntity(nEntity);
+    }
+
+    /// <inheritdoc />
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    public EntityUid? EnsureEntity<T>(NetEntity? nEntity, EntityUid callerEntity)
+    {
+        if (nEntity == null)
+            return null;
+
+        return EnsureEntity<T>(nEntity.Value, callerEntity);
+    }
+
+    /// <inheritdoc />
+    public EntityUid GetEntity(NetEntity nEntity)
+    {
+        if (nEntity == NetEntity.Invalid)
+            return EntityUid.Invalid;
+
+        return NetEntityLookup.GetValueOrDefault(nEntity);
+    }
+
+    /// <inheritdoc />
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    public EntityUid? GetEntity(NetEntity? nEntity)
+    {
+        if (nEntity == null)
+            return null;
+
+        return GetEntity(nEntity.Value);
+    }
+
+    /// <inheritdoc />
+    public NetEntity GetNetEntity(EntityUid uid, MetaDataComponent? metadata = null)
+    {
+        if (uid == EntityUid.Invalid)
+            return NetEntity.Invalid;
+
+        if (!MetaQuery.Resolve(uid, ref metadata))
+            return NetEntity.Invalid;
+
+        return metadata.NetEntity;
+    }
+
+    /// <inheritdoc />
+    public NetEntity? GetNetEntity(EntityUid? uid, MetaDataComponent? metadata = null)
+    {
+        if (uid == null)
+            return null;
+
+        return GetNetEntity(uid.Value, metadata);
+    }
+
+    #endregion
+
+    #region NetCoordinates
+
+    /// <inheritdoc />
+    public NetCoordinates GetNetCoordinates(EntityCoordinates coordinates, MetaDataComponent? metadata = null)
+    {
+        return new NetCoordinates(GetNetEntity(coordinates.EntityId, metadata), coordinates.Position);
+    }
+
+    /// <inheritdoc />
+    public NetCoordinates? GetNetCoordinates(EntityCoordinates? coordinates, MetaDataComponent? metadata = null)
+    {
+        if (coordinates == null)
+            return null;
+
+        return new NetCoordinates(GetNetEntity(coordinates.Value.EntityId, metadata), coordinates.Value.Position);
+    }
+
+    /// <inheritdoc />
+    public EntityCoordinates GetCoordinates(NetCoordinates coordinates)
+    {
+        return new EntityCoordinates(GetEntity(coordinates.NetEntity), coordinates.Position);
+    }
+
+    /// <inheritdoc />
+    public EntityCoordinates? GetCoordinates(NetCoordinates? coordinates)
+    {
+        if (coordinates == null)
+            return null;
+
+        return new EntityCoordinates(GetEntity(coordinates.Value.NetEntity), coordinates.Value.Position);
+    }
+
+    /// <inheritdoc />
+    public virtual EntityCoordinates EnsureCoordinates<T>(NetCoordinates netCoordinates, EntityUid callerEntity)
+    {
+        // See EnsureEntity
+        return GetCoordinates(netCoordinates);
+    }
+
+    /// <inheritdoc />
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    public EntityCoordinates? EnsureCoordinates<T>(NetCoordinates? netCoordinates, EntityUid callerEntity)
+    {
+        if (netCoordinates == null)
+            return null;
+
+        return EnsureCoordinates<T>(netCoordinates.Value, callerEntity);
+    }
+
+    #endregion
+
+    #region Collection helpers
+
+    /// <inheritdoc />
+    public HashSet<EntityUid> GetEntitySet(HashSet<NetEntity> netEntities)
+    {
+        var entities = new HashSet<EntityUid>();
+        entities.EnsureCapacity(netEntities.Count);
+
+        foreach (var netEntity in netEntities)
+        {
+            entities.Add(GetEntity(netEntity));
+        }
+
+        return entities;
+    }
+
+    /// <inheritdoc />
+    public List<EntityUid> GetEntityList(List<NetEntity> netEntities)
+    {
+        var entities = new List<EntityUid>(netEntities.Count);
+
+        foreach (var netEntity in netEntities)
+        {
+            entities.Add(GetEntity(netEntity));
+        }
+
+        return entities;
+    }
+
+    public HashSet<EntityUid> EnsureEntitySet<T>(HashSet<NetEntity> netEntities, EntityUid callerEntity)
+    {
+        var entities = new HashSet<EntityUid>(netEntities.Count);
+
+        foreach (var netEntity in netEntities)
+        {
+            entities.Add(EnsureEntity<T>(netEntity, callerEntity));
+        }
+
+        return entities;
+    }
+
+    /// <inheritdoc />
+    public List<EntityUid> EnsureEntityList<T>(List<NetEntity> netEntities, EntityUid callerEntity)
+    {
+        var entities = new List<EntityUid>(netEntities.Count);
+
+        foreach (var netEntity in netEntities)
+        {
+            entities.Add(EnsureEntity<T>(netEntity, callerEntity));
+        }
+
+        return entities;
+    }
+
+    /// <inheritdoc />
+    public List<EntityUid> GetEntityList(ICollection<NetEntity> netEntities)
+    {
+        var entities = new List<EntityUid>(netEntities.Count);
+        foreach (var netEntity in netEntities)
+        {
+            entities.Add(GetEntity(netEntity));
+        }
+
+        return entities;
+    }
+
+    /// <inheritdoc />
+    public List<EntityUid?> GetEntityList(List<NetEntity?> netEntities)
+    {
+        var entities = new List<EntityUid?>(netEntities.Count);
+
+        foreach (var netEntity in netEntities)
+        {
+            entities.Add(GetEntity(netEntity));
+        }
+
+        return entities;
+    }
+
+    /// <inheritdoc />
+    public EntityUid[] GetEntityArray(NetEntity[] netEntities)
+    {
+        var entities = new EntityUid[netEntities.Length];
+
+        for (var i = 0; i < netEntities.Length; i++)
+        {
+            entities[i] = GetEntity(netEntities[i]);
+        }
+
+        return entities;
+    }
+
+    /// <inheritdoc />
+    public EntityUid?[] GetEntityArray(NetEntity?[] netEntities)
+    {
+        var entities = new EntityUid?[netEntities.Length];
+
+        for (var i = 0; i < netEntities.Length; i++)
+        {
+            entities[i] = GetEntity(netEntities[i]);
+        }
+
+        return entities;
+    }
+
+    /// <inheritdoc />
+    public HashSet<NetEntity> GetNetEntitySet(HashSet<EntityUid> entities)
+    {
+        var newSet = new HashSet<NetEntity>(entities.Count);
+
+        foreach (var ent in entities)
+        {
+            MetaQuery.TryGetComponent(ent, out var metadata);
+            newSet.Add(GetNetEntity(ent, metadata));
+        }
+
+        return newSet;
+    }
+
+    /// <inheritdoc />
+    public List<NetEntity> GetNetEntityList(List<EntityUid> entities)
+    {
+        var netEntities = new List<NetEntity>(entities.Count);
+
+        foreach (var netEntity in entities)
+        {
+            netEntities.Add(GetNetEntity(netEntity));
+        }
+
+        return netEntities;
+    }
+
+    /// <inheritdoc />
+    public List<NetEntity> GetNetEntityList(IReadOnlyList<EntityUid> entities)
+    {
+        var netEntities = new List<NetEntity>(entities.Count);
+
+        foreach (var netEntity in entities)
+        {
+            netEntities.Add(GetNetEntity(netEntity));
+        }
+
+        return netEntities;
+    }
+
+    /// <inheritdoc />
+    public List<NetEntity> GetNetEntityList(ICollection<EntityUid> entities)
+    {
+        var netEntities = new List<NetEntity>(entities.Count);
+
+        foreach (var netEntity in entities)
+        {
+            netEntities.Add(GetNetEntity(netEntity));
+        }
+
+        return netEntities;
+    }
+
+    /// <inheritdoc />
+    public List<NetEntity?> GetNetEntityList(List<EntityUid?> entities)
+    {
+        var netEntities = new List<NetEntity?>(entities.Count);
+
+        foreach (var netEntity in entities)
+        {
+            netEntities.Add(GetNetEntity(netEntity));
+        }
+
+        return netEntities;
+    }
+
+    /// <inheritdoc />
+    public NetEntity[] GetNetEntityArray(EntityUid[] entities)
+    {
+        var netEntities = new NetEntity[entities.Length];
+
+        for (var i = 0; i < entities.Length; i++)
+        {
+            netEntities[i] = GetNetEntity(entities[i]);
+        }
+
+        return netEntities;
+    }
+
+    /// <inheritdoc />
+    public NetEntity?[] GetNetEntityArray(EntityUid?[] entities)
+    {
+        var netEntities = new NetEntity?[entities.Length];
+
+        for (var i = 0; i < entities.Length; i++)
+        {
+            netEntities[i] = GetNetEntity(entities[i]);
+        }
+
+        return netEntities;
+    }
+
+    /// <inheritdoc />
+    public HashSet<EntityCoordinates> GetEntitySet(HashSet<NetCoordinates> netEntities)
+    {
+        var entities = new HashSet<EntityCoordinates>(netEntities.Count);
+
+        foreach (var netCoordinates in netEntities)
+        {
+            entities.Add(GetCoordinates(netCoordinates));
+        }
+
+        return entities;
+    }
+
+    /// <inheritdoc />
+    public List<EntityCoordinates> GetEntityList(List<NetCoordinates> netEntities)
+    {
+        var entities = new List<EntityCoordinates>(netEntities.Count);
+
+        foreach (var netCoordinates in netEntities)
+        {
+            entities.Add(GetCoordinates(netCoordinates));
+        }
+
+        return entities;
+    }
+
+    /// <inheritdoc />
+    public List<EntityCoordinates> GetEntityList(ICollection<NetCoordinates> netEntities)
+    {
+        var entities = new List<EntityCoordinates>(netEntities.Count);
+
+        foreach (var netCoordinates in netEntities)
+        {
+            entities.Add(GetCoordinates(netCoordinates));
+        }
+
+        return entities;
+    }
+
+    /// <inheritdoc />
+    public List<EntityCoordinates?> GetEntityList(List<NetCoordinates?> netEntities)
+    {
+        var entities = new List<EntityCoordinates?>(netEntities.Count);
+
+        foreach (var netCoordinates in netEntities)
+        {
+            entities.Add(GetCoordinates(netCoordinates));
+        }
+
+        return entities;
+    }
+
+    /// <inheritdoc />
+    public EntityCoordinates[] GetEntityArray(NetCoordinates[] netEntities)
+    {
+        var entities = new EntityCoordinates[netEntities.Length];
+
+        for (var i = 0; i < netEntities.Length; i++)
+        {
+            entities[i] = GetCoordinates(netEntities[i]);
+        }
+
+        return entities;
+    }
+
+    /// <inheritdoc />
+    public EntityCoordinates?[] GetEntityArray(NetCoordinates?[] netEntities)
+    {
+        var entities = new EntityCoordinates?[netEntities.Length];
+
+        for (var i = 0; i < netEntities.Length; i++)
+        {
+            entities[i] = GetCoordinates(netEntities[i]);
+        }
+
+        return entities;
+    }
+
+    /// <inheritdoc />
+    public HashSet<NetCoordinates> GetNetCoordinatesSet(HashSet<EntityCoordinates> entities)
+    {
+        var newSet = new HashSet<NetCoordinates>(entities.Count);
+
+        foreach (var coordinates in entities)
+        {
+            newSet.Add(GetNetCoordinates(coordinates));
+        }
+
+        return newSet;
+    }
+
+    /// <inheritdoc />
+    public List<NetCoordinates> GetNetCoordinatesList(List<EntityCoordinates> entities)
+    {
+        var netEntities = new List<NetCoordinates>(entities.Count);
+
+        foreach (var netCoordinates in entities)
+        {
+            netEntities.Add(GetNetCoordinates(netCoordinates));
+        }
+
+        return netEntities;
+    }
+
+    /// <inheritdoc />
+    public List<NetCoordinates> GetNetCoordinatesList(ICollection<EntityCoordinates> entities)
+    {
+        var netEntities = new List<NetCoordinates>(entities.Count);
+
+        foreach (var netCoordinates in entities)
+        {
+            netEntities.Add(GetNetCoordinates(netCoordinates));
+        }
+
+        return netEntities;
+    }
+
+    /// <inheritdoc />
+    public List<NetCoordinates?> GetNetCoordinatesList(List<EntityCoordinates?> entities)
+    {
+        var netEntities = new List<NetCoordinates?>(entities.Count);
+
+        foreach (var netCoordinates in entities)
+        {
+            netEntities.Add(GetNetCoordinates(netCoordinates));
+        }
+
+        return netEntities;
+    }
+
+    /// <inheritdoc />
+    public NetCoordinates[] GetNetCoordinatesArray(EntityCoordinates[] entities)
+    {
+        var netEntities = new NetCoordinates[entities.Length];
+
+        for (var i = 0; i < entities.Length; i++)
+        {
+            netEntities[i] = GetNetCoordinates(entities[i]);
+        }
+
+        return netEntities;
+    }
+
+    /// <inheritdoc />
+    public NetCoordinates?[] GetNetCoordinatesArray(EntityCoordinates?[] entities)
+    {
+        var netEntities = new NetCoordinates?[entities.Length];
+
+        for (var i = 0; i < entities.Length; i++)
+        {
+            netEntities[i] = GetNetCoordinates(entities[i]);
+        }
+
+        return netEntities;
+    }
+
+    #endregion
+}

Robust.Shared/GameObjects/EntityManager.Spawn.cs

@@ -13,11 +13,11 @@ public partial class EntityManager
     // This method will soon be marked as obsolete.
     public EntityUid SpawnEntity(string? protoName, EntityCoordinates coordinates, ComponentRegistry? overrides = null)
         => SpawnAttachedTo(protoName, coordinates, overrides);
-    
+
     // This method will soon be marked as obsolete.
     public EntityUid SpawnEntity(string? protoName, MapCoordinates coordinates, ComponentRegistry? overrides = null)
         => Spawn(protoName, coordinates, overrides);
-    
+
     [MethodImpl(MethodImplOptions.AggressiveInlining)]
     public EntityUid[] SpawnEntitiesAttachedTo(EntityCoordinates coordinates, params string?[] protoNames)
     {
@@ -100,8 +100,8 @@ public partial class EntityManager
 
         if (!xform.ParentUid.IsValid())
             return false;
-        
-        if (!_metaQuery.TryGetComponent(target, out var meta))
+
+        if (!MetaQuery.TryGetComponent(target, out var meta))
             return false;
 
         if ((meta.Flags & MetaDataFlags.InContainer) == 0)
@@ -135,7 +135,7 @@ public partial class EntityManager
         EntityUid containerUid,
         string containerId,
         [NotNullWhen(true)] out EntityUid? uid,
-        ContainerManagerComponent? containerComp = null, 
+        ContainerManagerComponent? containerComp = null,
         ComponentRegistry? overrides = null)
     {
         uid = null;
@@ -160,7 +160,7 @@ public partial class EntityManager
         xform ??= _xformQuery.GetComponent(target);
         if (!xform.ParentUid.IsValid())
             return Spawn(protoName);
-        
+
         var uid = Spawn(protoName, overrides);
         _xforms.PlaceNextToOrDrop(uid, target);
         return uid;
@@ -180,7 +180,7 @@ public partial class EntityManager
              || !containerComp.Containers.TryGetValue(containerId, out var container)
              || !container.Insert(uid, this))
         {
-            
+
             xform ??= _xformQuery.GetComponent(containerUid);
             if (xform.ParentUid.IsValid())
                 _xforms.PlaceNextToOrDrop(uid, containerUid, targetXform: xform);

Robust.Shared/GameObjects/EntityManager.cs

@@ -11,7 +11,6 @@ using System.Collections.Generic;
 using System.Diagnostics.CodeAnalysis;
 using System.Linq;
 using System.Runtime.CompilerServices;
-using Robust.Shared.Physics;
 using Robust.Shared.Serialization.Markdown.Mapping;
 
 namespace Robust.Shared.GameObjects
@@ -38,7 +37,7 @@ namespace Robust.Shared.GameObjects
         // positions on spawn....
         private SharedTransformSystem _xforms = default!;
 
-        private EntityQuery<MetaDataComponent> _metaQuery;
+        protected EntityQuery<MetaDataComponent> MetaQuery;
         private EntityQuery<TransformComponent> _xformQuery;
 
         #endregion Dependencies
@@ -68,14 +67,16 @@ namespace Robust.Shared.GameObjects
 
         private EntityEventBus _eventBus = null!;
 
-        protected virtual int NextEntityUid { get; set; } = (int) EntityUid.FirstUid;
+        protected int NextEntityUid = (int) EntityUid.FirstUid;
+
+        protected int NextNetworkId = (int) NetEntity.First;
 
         /// <inheritdoc />
         public IEventBus EventBus => _eventBus;
 
         public event Action<EntityUid>? EntityAdded;
         public event Action<EntityUid>? EntityInitialized;
-        public event Action<EntityUid>? EntityDeleted;
+        public event Action<EntityUid, MetaDataComponent>? EntityDeleted;
 
         /// <summary>
         /// Raised when an entity is queued for deletion. Not raised if an entity is deleted.
@@ -123,7 +124,7 @@ namespace Robust.Shared.GameObjects
         /// </summary>
         public bool IsDefault(EntityUid uid)
         {
-            if (!_metaQuery.TryGetComponent(uid, out var metadata) || metadata.EntityPrototype == null)
+            if (!MetaQuery.TryGetComponent(uid, out var metadata) || metadata.EntityPrototype == null)
                 return false;
 
             var prototype = metadata.EntityPrototype;
@@ -232,7 +233,7 @@ namespace Robust.Shared.GameObjects
             _eventBus.CalcOrdering();
             _mapSystem = System<SharedMapSystem>();
             _xforms = System<SharedTransformSystem>();
-            _metaQuery = GetEntityQuery<MetaDataComponent>();
+            MetaQuery = GetEntityQuery<MetaDataComponent>();
             _xformQuery = GetEntityQuery<TransformComponent>();
         }
 
@@ -304,19 +305,19 @@ namespace Robust.Shared.GameObjects
 
         public EntityUid CreateEntityUninitialized(string? prototypeName, EntityUid euid, ComponentRegistry? overrides = null)
         {
-            return CreateEntity(prototypeName, euid, overrides);
+            return CreateEntity(prototypeName, overrides);
         }
 
         /// <inheritdoc />
         public virtual EntityUid CreateEntityUninitialized(string? prototypeName, ComponentRegistry? overrides = null)
         {
-            return CreateEntity(prototypeName, default, overrides);
+            return CreateEntity(prototypeName, overrides);
         }
 
         /// <inheritdoc />
         public virtual EntityUid CreateEntityUninitialized(string? prototypeName, EntityCoordinates coordinates, ComponentRegistry? overrides = null)
         {
-            var newEntity = CreateEntity(prototypeName, default, overrides);
+            var newEntity = CreateEntity(prototypeName, overrides);
             _xforms.SetCoordinates(newEntity, _xformQuery.GetComponent(newEntity), coordinates, unanchor: false);
             return newEntity;
         }
@@ -324,7 +325,7 @@ namespace Robust.Shared.GameObjects
         /// <inheritdoc />
         public virtual EntityUid CreateEntityUninitialized(string? prototypeName, MapCoordinates coordinates, ComponentRegistry? overrides = null)
         {
-            var newEntity = CreateEntity(prototypeName, default, overrides);
+            var newEntity = CreateEntity(prototypeName, overrides);
             var transform = _xformQuery.GetComponent(newEntity);
 
             if (coordinates.MapId == MapId.Nullspace)
@@ -415,14 +416,10 @@ namespace Robust.Shared.GameObjects
             if (!Started)
                 return;
 
-            var metaQuery = GetEntityQuery<MetaDataComponent>();
-            var xformQuery = GetEntityQuery<TransformComponent>();
-            var xformSys = EntitySysManager.GetEntitySystem<SharedTransformSystem>();
-
             // Networking blindly spams entities at this function, they can already be
             // deleted from being a child of a previously deleted entity
             // TODO: Why does networking need to send deletes for child entities?
-            if (!metaQuery.TryGetComponent(e, out var meta) || meta.EntityDeleted)
+            if (!MetaQuery.TryGetComponent(e, out var meta) || meta.EntityDeleted)
                 return;
 
             if (meta.EntityLifeStage == EntityLifeStage.Terminating)
@@ -436,19 +433,17 @@ namespace Robust.Shared.GameObjects
             }
 
             // Notify all entities they are being terminated prior to detaching & deleting
-            RecursiveFlagEntityTermination(e, meta, metaQuery, xformQuery);
+            RecursiveFlagEntityTermination(e, meta);
 
             // Then actually delete them
-            RecursiveDeleteEntity(e, meta, metaQuery, xformQuery, xformSys);
+            RecursiveDeleteEntity(e, meta);
         }
 
         private void RecursiveFlagEntityTermination(
             EntityUid uid,
-            MetaDataComponent metadata,
-            EntityQuery<MetaDataComponent> metaQuery,
-            EntityQuery<TransformComponent> xformQuery)
+            MetaDataComponent metadata)
         {
-            var transform = xformQuery.GetComponent(uid);
+            var transform = _xformQuery.GetComponent(uid);
             metadata.EntityLifeStage = EntityLifeStage.Terminating;
 
             try
@@ -463,27 +458,24 @@ namespace Robust.Shared.GameObjects
 
             foreach (var child in transform._children)
             {
-                if (!metaQuery.TryGetComponent(child, out var childMeta) || childMeta.EntityDeleted)
+                if (!MetaQuery.TryGetComponent(child, out var childMeta) || childMeta.EntityDeleted)
                 {
                     _sawmill.Error($"A deleted entity was still the transform child of another entity. Parent: {ToPrettyString(uid, metadata)}.");
                     transform._children.Remove(child);
                     continue;
                 }
 
-                RecursiveFlagEntityTermination(child, childMeta, metaQuery, xformQuery);
+                RecursiveFlagEntityTermination(child, childMeta);
             }
         }
 
         private void RecursiveDeleteEntity(
             EntityUid uid,
-            MetaDataComponent metadata,
-            EntityQuery<MetaDataComponent> metaQuery,
-            EntityQuery<TransformComponent> xformQuery,
-            SharedTransformSystem xformSys)
+            MetaDataComponent metadata)
         {
             // Note about this method: #if EXCEPTION_TOLERANCE is not used here because we're gonna it in the future...
-
-            var transform = xformQuery.GetComponent(uid);
+            var netEntity = GetNetEntity(uid, metadata);
+            var transform = _xformQuery.GetComponent(uid);
 
             // Detach the base entity to null before iterating over children
             // This also ensures that the entity-lookup updates don't have to be re-run for every child (which recurses up the transform hierarchy).
@@ -491,7 +483,7 @@ namespace Robust.Shared.GameObjects
             {
                 try
                 {
-                    xformSys.DetachParentToNull(uid, transform);
+                    _xforms.DetachParentToNull(uid, transform);
                 }
                 catch (Exception e)
                 {
@@ -503,7 +495,7 @@ namespace Robust.Shared.GameObjects
             {
                 try
                 {
-                    RecursiveDeleteEntity(child, metaQuery.GetComponent(child), metaQuery, xformQuery, xformSys);
+                    RecursiveDeleteEntity(child, MetaQuery.GetComponent(child));
                 }
                 catch(Exception e)
                 {
@@ -536,7 +528,7 @@ namespace Robust.Shared.GameObjects
 
             try
             {
-                EntityDeleted?.Invoke(uid);
+                EntityDeleted?.Invoke(uid, metadata);
             }
             catch (Exception e)
             {
@@ -545,6 +537,8 @@ namespace Robust.Shared.GameObjects
 
             _eventBus.OnEntityDeleted(uid);
             Entities.Remove(uid);
+            // Need to get the ID above before MetadataComponent shutdown but only remove it after everything else is done.
+            NetEntityLookup.Remove(netEntity);
         }
 
         public virtual void QueueDeleteEntity(EntityUid uid)
@@ -574,7 +568,7 @@ namespace Robust.Shared.GameObjects
             if (uid == null)
                 return false;
 
-            return _metaQuery.Resolve(uid.Value, ref metadata) && metadata.EntityPaused;
+            return MetaQuery.Resolve(uid.Value, ref metadata) && metadata.EntityPaused;
         }
 
         public bool Deleted(EntityUid uid)
@@ -608,10 +602,9 @@ namespace Robust.Shared.GameObjects
         /// </summary>
         private protected EntityUid AllocEntity(
             EntityPrototype? prototype,
-            out MetaDataComponent metadata,
-            EntityUid uid = default)
+            out MetaDataComponent metadata)
         {
-            var entity = AllocEntity(out metadata, uid);
+            var entity = AllocEntity(out metadata);
             metadata._entityPrototype = prototype;
             Dirty(entity, metadata, metadata);
             return entity;
@@ -620,25 +613,30 @@ namespace Robust.Shared.GameObjects
         /// <summary>
         ///     Allocates an entity and stores it but does not load components or do initialization.
         /// </summary>
-        private EntityUid AllocEntity(out MetaDataComponent metadata, EntityUid uid = default)
+        private EntityUid AllocEntity(out MetaDataComponent metadata)
         {
-            if (uid == default)
-            {
-                uid = GenerateEntityUid();
-            }
+            var uid = GenerateEntityUid();
 
+#if DEBUG
             if (EntityExists(uid))
             {
                 throw new InvalidOperationException($"UID already taken: {uid}");
             }
+#endif
 
             // we want this called before adding components
             EntityAdded?.Invoke(uid);
             _eventBus.OnEntityAdded(uid);
+            var netEntity = GenerateNetEntity();
 
+            metadata = new MetaDataComponent
+            {
 #pragma warning disable CS0618
-            metadata = new MetaDataComponent { Owner = uid };
+                Owner = uid,
 #pragma warning restore CS0618
+            };
+
+            SetNetEntity(uid, netEntity, metadata);
 
             Entities.Add(uid);
             // add the required MetaDataComponent directly.
@@ -653,23 +651,23 @@ namespace Robust.Shared.GameObjects
         /// <summary>
         ///     Allocates an entity and loads components but does not do initialization.
         /// </summary>
-        private protected virtual EntityUid CreateEntity(string? prototypeName, EntityUid uid = default, IEntityLoadContext? context = null)
+        private protected virtual EntityUid CreateEntity(string? prototypeName, IEntityLoadContext? context = null)
         {
             if (prototypeName == null)
-                return AllocEntity(out _, uid);
+                return AllocEntity(out _);
 
             if (!PrototypeManager.TryIndex<EntityPrototype>(prototypeName, out var prototype))
                 throw new EntityCreationException($"Attempted to spawn an entity with an invalid prototype: {prototypeName}");
 
-            return CreateEntity(prototype, uid, context);
+            return CreateEntity(prototype, context);
         }
 
         /// <summary>
         ///     Allocates an entity and loads components but does not do initialization.
         /// </summary>
-        private protected EntityUid CreateEntity(EntityPrototype prototype, EntityUid uid = default, IEntityLoadContext? context = null)
+        private protected EntityUid CreateEntity(EntityPrototype prototype, IEntityLoadContext? context = null)
         {
-            var entity = AllocEntity(prototype, out var metadata, uid);
+            var entity = AllocEntity(prototype, out var metadata);
             try
             {
                 EntityPrototype.LoadEntity(metadata.EntityPrototype, entity, ComponentFactory, this, _serManager, context);
@@ -686,7 +684,7 @@ namespace Robust.Shared.GameObjects
 
         private protected void LoadEntity(EntityUid entity, IEntityLoadContext? context)
         {
-            EntityPrototype.LoadEntity(_metaQuery.GetComponent(entity).EntityPrototype, entity, ComponentFactory, this, _serManager, context);
+            EntityPrototype.LoadEntity(MetaQuery.GetComponent(entity).EntityPrototype, entity, ComponentFactory, this, _serManager, context);
         }
 
         private protected void LoadEntity(EntityUid entity, IEntityLoadContext? context, EntityPrototype? prototype)
@@ -698,7 +696,7 @@ namespace Robust.Shared.GameObjects
         {
             try
             {
-                var meta = _metaQuery.GetComponent(entity);
+                var meta = MetaQuery.GetComponent(entity);
                 InitializeEntity(entity, meta);
                 StartEntity(entity);
 
@@ -747,6 +745,12 @@ namespace Robust.Shared.GameObjects
             return ToPrettyString(uid, metadata);
         }
 
+        /// <inheritdoc />
+        public EntityStringRepresentation ToPrettyString(NetEntity netEntity)
+        {
+            return ToPrettyString(GetEntity(netEntity));
+        }
+
         private EntityStringRepresentation ToPrettyString(EntityUid uid, MetaDataComponent metadata)
         {
             return new EntityStringRepresentation(uid, metadata.EntityDeleted, metadata.EntityName, metadata.EntityPrototype?.ID);
@@ -764,12 +768,16 @@ namespace Robust.Shared.GameObjects
         /// <summary>
         ///     Factory for generating a new EntityUid for an entity currently being created.
         /// </summary>
-        /// <inheritdoc />
-        protected virtual EntityUid GenerateEntityUid()
+        internal EntityUid GenerateEntityUid()
         {
-            return new(NextEntityUid++);
+            return new EntityUid(NextEntityUid++);
         }
 
+        /// <summary>
+        /// Generates a unique network id and increments <see cref="NextNetworkId"/>
+        /// </summary>
+        protected virtual NetEntity GenerateNetEntity() => new(NextNetworkId++);
+
         private sealed class EntityDiffContext : ISerializationContext
         {
             public SerializationManager.SerializerProvider SerializerProvider { get; }

Robust.Shared/GameObjects/EntityState.cs

@@ -9,7 +9,10 @@ namespace Robust.Shared.GameObjects
     [Serializable, NetSerializable]
     public sealed class EntityState
     {
-        public EntityUid Uid { get; }
+        /// <summary>
+        /// Network identifier for the entity.
+        /// </summary>
+        public NetEntity NetEntity;
 
         public NetListAsArray<ComponentChange> ComponentChanges { get; }
 
@@ -23,9 +26,9 @@ namespace Robust.Shared.GameObjects
         /// </summary>
         public HashSet<ushort>? NetComponents;
 
-        public EntityState(EntityUid uid, NetListAsArray<ComponentChange> changedComponents, GameTick lastModified, HashSet<ushort>? netComps = null)
+        public EntityState(NetEntity netEntity, NetListAsArray<ComponentChange> changedComponents, GameTick lastModified, HashSet<ushort>? netComps = null)
         {
-            Uid = uid;
+            NetEntity = netEntity;
             ComponentChanges = changedComponents;
             EntityLastModified = lastModified;
             NetComponents = netComps;

Robust.Shared/GameObjects/EntitySystem.Proxy.cs

@@ -403,6 +403,13 @@ public partial class EntitySystem
         return EntityManager.ToPrettyString(uid);
     }
 
+    /// <inheritdoc cref="IEntityManager.ToPrettyString"/>
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    protected EntityStringRepresentation ToPrettyString(NetEntity netEntity)
+    {
+        return EntityManager.ToPrettyString(netEntity);
+    }
+
     #endregion
 
     #region Component Get
@@ -886,4 +893,344 @@ public partial class EntitySystem
     }
 
     #endregion
+
+    #region NetEntities
+
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    protected bool IsClientSide(EntityUid entity)
+    {
+        return EntityManager.IsClientSide(entity);
+    }
+
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    public bool TryGetEntity(NetEntity nEntity, [NotNullWhen(true)] out EntityUid? entity)
+    {
+        return EntityManager.TryGetEntity(nEntity, out entity);
+    }
+
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    public bool TryGetEntity(NetEntity? nEntity, [NotNullWhen(true)] out EntityUid? entity)
+    {
+        return EntityManager.TryGetEntity(nEntity, out entity);
+    }
+
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    public bool TryGetNetEntity(EntityUid uid, [NotNullWhen(true)] out NetEntity? netEntity, MetaDataComponent? metadata = null)
+    {
+        return EntityManager.TryGetNetEntity(uid, out netEntity);
+    }
+
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    public bool TryGetNetEntity(EntityUid? uid, [NotNullWhen(true)] out NetEntity? netEntity, MetaDataComponent? metadata = null)
+    {
+        return EntityManager.TryGetNetEntity(uid, out netEntity);
+    }
+
+    /// <summary>
+    ///     Returns the <see cref="NetEntity"/> of an entity. Returns <see cref="NetEntity.Invalid"/> if it doesn't exist.
+    /// </summary>
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    protected NetEntity GetNetEntity(EntityUid uid, MetaDataComponent? metadata = null)
+    {
+        return EntityManager.GetNetEntity(uid, metadata);
+    }
+
+    /// <summary>
+    ///     Returns the <see cref="NetEntity"/> of an entity.  Logs an error if the entity does not exist.
+    /// </summary>
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    protected NetEntity? GetNetEntity(EntityUid? uid, MetaDataComponent? metadata = null)
+    {
+        return EntityManager.GetNetEntity(uid, metadata);
+    }
+
+    /// <summary>
+    ///     Returns the <see cref="NetEntity"/> of an entity or creates a new entity if none exists.
+    /// </summary>
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    protected EntityUid EnsureEntity<T>(NetEntity netEntity, EntityUid callerEntity)
+    {
+        return EntityManager.EnsureEntity<T>(netEntity, callerEntity);
+    }
+
+    /// <summary>
+    ///     Returns the <see cref="NetEntity"/> of an entity or creates a new one if not null.
+    /// </summary>
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    protected EntityUid? EnsureEntity<T>(NetEntity? netEntity, EntityUid callerEntity)
+    {
+        return EntityManager.EnsureEntity<T>(netEntity, callerEntity);
+    }
+
+    /// <summary>
+    ///     Returns the <see cref="NetCoordinates"/> of an entity or creates a new entity if none exists.
+    /// </summary>
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    protected EntityCoordinates EnsureCoordinates<T>(NetCoordinates netCoordinates, EntityUid callerEntity)
+    {
+        return EntityManager.EnsureCoordinates<T>(netCoordinates, callerEntity);
+    }
+
+    /// <summary>
+    ///     Returns the <see cref="NetCoordinates"/> of an entity or creates a new one if not null.
+    /// </summary>
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    protected EntityCoordinates? EnsureCoordinates<T>(NetCoordinates? netCoordinates, EntityUid callerEntity)
+    {
+        return EntityManager.EnsureCoordinates<T>(netCoordinates, callerEntity);
+    }
+
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    public HashSet<EntityUid> EnsureEntitySet<T>(HashSet<NetEntity> netEntities, EntityUid callerEntity)
+    {
+        return EntityManager.EnsureEntitySet<T>(netEntities, callerEntity);
+    }
+
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    public List<EntityUid> EnsureEntityList<T>(List<NetEntity> netEntities, EntityUid callerEntity)
+    {
+        return EntityManager.EnsureEntityList<T>(netEntities, callerEntity);
+    }
+
+    /// <summary>
+    ///     Returns the <see cref="EntityUid"/> of a <see cref="NetEntity"/>. Returns <see cref="EntityUid.Invalid"/> if it doesn't exist.
+    /// </summary>
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    protected EntityUid GetEntity(NetEntity netEntity)
+    {
+        return EntityManager.GetEntity(netEntity);
+    }
+
+    /// <summary>
+    ///     Returns the <see cref="EntityUid"/> of a <see cref="NetEntity"/>. Returns <see cref="EntityUid.Invalid"/> if it doesn't exist.
+    /// </summary>
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    protected EntityUid? GetEntity(NetEntity? netEntity)
+    {
+        return EntityManager.GetEntity(netEntity);
+    }
+
+    /// <summary>
+    ///     Returns the <see cref="NetEntity"/> versions of the supplied entities. Logs an error if the entities do not exist.
+    /// </summary>
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    protected HashSet<NetEntity> GetNetEntitySet(HashSet<EntityUid> uids)
+    {
+        return EntityManager.GetNetEntitySet(uids);
+    }
+
+    /// <summary>
+    ///     Returns the <see cref="EntityUid"/> versions of the supplied <see cref="NetEntity"/>. Returns <see cref="EntityUid.Invalid"/> if it doesn't exist.
+    /// </summary>
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    protected HashSet<EntityUid> GetEntitySet(HashSet<NetEntity> netEntities)
+    {
+        return EntityManager.GetEntitySet(netEntities);
+    }
+
+    /// <summary>
+    ///     Returns the <see cref="NetEntity"/> versions of the supplied entities. Logs an error if the entities do not exist.
+    /// </summary>
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    protected List<NetEntity> GetNetEntityList(ICollection<EntityUid> uids)
+    {
+        return EntityManager.GetNetEntityList(uids);
+    }
+
+    /// <summary>
+    ///     Returns the <see cref="NetEntity"/> versions of the supplied entities. Logs an error if the entities do not exist.
+    /// </summary>
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    protected List<NetEntity> GetNetEntityList(IReadOnlyList<EntityUid> uids)
+    {
+        return EntityManager.GetNetEntityList(uids);
+    }
+
+    /// <summary>
+    ///     Returns the <see cref="EntityUid"/> versions of the supplied <see cref="NetEntity"/>. Returns <see cref="EntityUid.Invalid"/> if it doesn't exist.
+    /// </summary>
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    protected List<EntityUid> GetEntityList(ICollection<NetEntity> netEntities)
+    {
+        return EntityManager.GetEntityList(netEntities);
+    }
+
+    /// <summary>
+    ///     Returns the <see cref="NetEntity"/> versions of the supplied entities. Logs an error if the entities do not exist.
+    /// </summary>
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    protected List<NetEntity> GetNetEntityList(List<EntityUid> uids)
+    {
+        return EntityManager.GetNetEntityList(uids);
+    }
+
+    /// <summary>
+    ///     Returns the <see cref="EntityUid"/> versions of the supplied <see cref="NetEntity"/>. Returns <see cref="EntityUid.Invalid"/> if it doesn't exist.
+    /// </summary>
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    protected List<EntityUid> GetEntityList(List<NetEntity> netEntities)
+    {
+        return EntityManager.GetEntityList(netEntities);
+    }
+
+    /// <summary>
+    ///     Returns the <see cref="NetEntity"/> versions of the supplied entities. Logs an error if the entities do not exist.
+    /// </summary>
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    protected List<NetEntity?> GetNetEntityList(List<EntityUid?> uids)
+    {
+        return EntityManager.GetNetEntityList(uids);
+    }
+
+    /// <summary>
+    ///     Returns the <see cref="EntityUid"/> versions of the supplied <see cref="NetEntity"/>. Returns <see cref="EntityUid.Invalid"/> if it doesn't exist.
+    /// </summary>
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    protected List<EntityUid?> GetEntityList(List<NetEntity?> netEntities)
+    {
+        return EntityManager.GetEntityList(netEntities);
+    }
+
+    /// <summary>
+    ///     Returns the <see cref="NetEntity"/> versions of the supplied entities. Logs an error if the entities do not exist.
+    /// </summary>
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    protected NetEntity[] GetNetEntityArray(EntityUid[] uids)
+    {
+        return EntityManager.GetNetEntityArray(uids);
+    }
+
+    /// <summary>
+    ///     Returns the <see cref="EntityUid"/> versions of the supplied <see cref="NetEntity"/>. Returns <see cref="EntityUid.Invalid"/> if it doesn't exist.
+    /// </summary>
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    protected EntityUid[] GetEntityArray(NetEntity[] netEntities)
+    {
+        return EntityManager.GetEntityArray(netEntities);
+    }
+
+    /// <summary>
+    ///     Returns the <see cref="NetEntity"/> versions of the supplied entities.  Logs an error if the entities do not exist.
+    /// </summary>
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    protected NetEntity?[] GetNetEntityArray(EntityUid?[] uids)
+    {
+        return EntityManager.GetNetEntityArray(uids);
+    }
+
+    /// <summary>
+    ///     Returns the <see cref="EntityUid"/> versions of the supplied <see cref="NetEntity"/>. Returns <see cref="EntityUid.Invalid"/> if it doesn't exist.
+    /// </summary>
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    protected EntityUid?[] GetEntityArray(NetEntity?[] netEntities)
+    {
+        return EntityManager.GetEntityArray(netEntities);
+    }
+
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    protected NetCoordinates GetNetCoordinates(EntityCoordinates coordinates, MetaDataComponent? metadata = null)
+    {
+        return EntityManager.GetNetCoordinates(coordinates, metadata);
+    }
+
+    /// <summary>
+    ///     Returns the <see cref="NetEntity"/> of an entity. Returns <see cref="NetEntity.Invalid"/> if it doesn't exist.
+    /// </summary>
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    protected NetCoordinates? GetNetCoordinates(EntityCoordinates? coordinates, MetaDataComponent? metadata = null)
+    {
+        return EntityManager.GetNetCoordinates(coordinates, metadata);
+    }
+
+    /// <summary>
+    ///     Returns the <see cref="EntityUid"/> of a <see cref="NetEntity"/>. Returns <see cref="EntityUid.Invalid"/> if it doesn't exist.
+    /// </summary>
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    protected EntityCoordinates GetCoordinates(NetCoordinates netEntity)
+    {
+        return EntityManager.GetCoordinates(netEntity);
+    }
+
+    /// <summary>
+    ///     Returns the <see cref="EntityUid"/> of a <see cref="NetEntity"/>. Returns <see cref="EntityUid.Invalid"/> if it doesn't exist.
+    /// </summary>
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    protected EntityCoordinates? GetCoordinates(NetCoordinates? netEntity)
+    {
+        return EntityManager.GetCoordinates(netEntity);
+    }
+
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    public HashSet<EntityCoordinates> GetEntitySet(HashSet<NetCoordinates> netEntities)
+    {
+        return EntityManager.GetEntitySet(netEntities);
+    }
+
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    public List<EntityCoordinates> GetEntityList(List<NetCoordinates> netEntities)
+    {
+        return EntityManager.GetEntityList(netEntities);
+    }
+
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    public List<EntityCoordinates> GetEntityList(ICollection<NetCoordinates> netEntities)
+    {
+        return EntityManager.GetEntityList(netEntities);
+    }
+
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    public List<EntityCoordinates?> GetEntityList(List<NetCoordinates?> netEntities)
+    {
+        return EntityManager.GetEntityList(netEntities);
+    }
+
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    public EntityCoordinates[] GetEntityArray(NetCoordinates[] netEntities)
+    {
+        return EntityManager.GetEntityArray(netEntities);
+    }
+
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    public EntityCoordinates?[] GetEntityArray(NetCoordinates?[] netEntities)
+    {
+        return EntityManager.GetEntityArray(netEntities);
+    }
+
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    public HashSet<NetCoordinates> GetNetCoordinatesSet(HashSet<EntityCoordinates> entities)
+    {
+        return EntityManager.GetNetCoordinatesSet(entities);
+    }
+
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    public List<NetCoordinates> GetNetCoordinatesList(List<EntityCoordinates> entities)
+    {
+        return EntityManager.GetNetCoordinatesList(entities);
+    }
+
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    public List<NetCoordinates> GetNetCoordinatesList(ICollection<EntityCoordinates> entities)
+    {
+        return EntityManager.GetNetCoordinatesList(entities);
+    }
+
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    public List<NetCoordinates?> GetNetCoordinatesList(List<EntityCoordinates?> entities)
+    {
+        return EntityManager.GetNetCoordinatesList(entities);
+    }
+
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    public NetCoordinates[] GetNetCoordinatesArray(EntityCoordinates[] entities)
+    {
+        return EntityManager.GetNetCoordinatesArray(entities);
+    }
+
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    public NetCoordinates?[] GetNetCoordinatesArray(EntityCoordinates?[] entities)
+    {
+        return EntityManager.GetNetCoordinatesArray(entities);
+    }
+
+    #endregion
 }

Robust.Shared/GameObjects/EntitySystemMessages/AudioMessages.cs

@@ -31,14 +31,14 @@ public sealed class PlayAudioGlobalMessage : AudioMessage
 [Serializable, NetSerializable]
 public sealed class PlayAudioPositionalMessage : AudioMessage
 {
-    public EntityCoordinates Coordinates { get; set; }
-    public EntityCoordinates FallbackCoordinates { get; set; }
+    public NetCoordinates Coordinates { get; set; }
+    public NetCoordinates FallbackCoordinates { get; set; }
 }
 
 [Serializable, NetSerializable]
 public sealed class PlayAudioEntityMessage : AudioMessage
 {
-    public EntityUid EntityUid { get; set; }
-    public EntityCoordinates Coordinates { get; set; }
-    public EntityCoordinates FallbackCoordinates { get; set; }
+    public NetEntity NetEntity { get; set; }
+    public NetCoordinates Coordinates { get; set; }
+    public NetCoordinates FallbackCoordinates { get; set; }
 }

Robust.Shared/GameObjects/EntityUid.cs

@@ -2,7 +2,6 @@ using System;
 using JetBrains.Annotations;
 using Robust.Shared.IoC;
 using Robust.Shared.Prototypes;
-using Robust.Shared.Serialization;
 using Robust.Shared.Serialization.Manager.Attributes;
 using Robust.Shared.Timing;
 using Robust.Shared.Utility;
@@ -14,15 +13,10 @@ namespace Robust.Shared.GameObjects
     ///     This type contains a network identification number of an entity.
     ///     This can be used by the EntityManager to access an entity
     /// </summary>
-    [Serializable, NetSerializable, CopyByRef]
+    [CopyByRef]
     public readonly struct EntityUid : IEquatable<EntityUid>, IComparable<EntityUid>, ISpanFormattable
     {
-        /// <summary>
-        ///     If this bit is set on a UID, it's client sided.
-        ///     Use <see cref="IsClientSide" /> to check this.
-        /// </summary>
-        internal const int ClientUid = 2 << 29;
-        readonly int _uid;
+        public readonly int Id;
 
         /// <summary>
         ///     An Invalid entity UID you can compare against.
@@ -37,9 +31,9 @@ namespace Robust.Shared.GameObjects
         /// <summary>
         ///     Creates an instance of this structure, with the given network ID.
         /// </summary>
-        public EntityUid(int uid)
+        public EntityUid(int id)
         {
-            _uid = uid;
+            Id = id;
         }
 
         public bool Valid => IsValid();
@@ -49,14 +43,7 @@ namespace Robust.Shared.GameObjects
         /// </summary>
         public static EntityUid Parse(ReadOnlySpan<char> uid)
         {
-            if (uid.StartsWith("c"))
-            {
-                return new EntityUid(int.Parse(uid[1..]) | ClientUid);
-            }
-            else
-            {
-                return new EntityUid(int.Parse(uid));
-            }
+            return new EntityUid(int.Parse(uid));
         }
 
         public static bool TryParse(ReadOnlySpan<char> uid, out EntityUid entityUid)
@@ -80,19 +67,13 @@ namespace Robust.Shared.GameObjects
         [Pure]
         public bool IsValid()
         {
-            return _uid > 0;
-        }
-
-        [Pure]
-        public bool IsClientSide()
-        {
-            return (_uid & (2 << 29)) != 0;
+            return Id > 0;
         }
 
         /// <inheritdoc />
         public bool Equals(EntityUid other)
         {
-            return _uid == other._uid;
+            return Id == other.Id;
         }
 
         /// <inheritdoc />
@@ -105,7 +86,7 @@ namespace Robust.Shared.GameObjects
         /// <inheritdoc />
         public override int GetHashCode()
         {
-            return _uid;
+            return Id;
         }
 
         /// <summary>
@@ -113,7 +94,7 @@ namespace Robust.Shared.GameObjects
         /// </summary>
         public static bool operator ==(EntityUid a, EntityUid b)
         {
-            return a._uid == b._uid;
+            return a.Id == b.Id;
         }
 
         /// <summary>
@@ -130,17 +111,13 @@ namespace Robust.Shared.GameObjects
         /// </summary>
         public static explicit operator int(EntityUid self)
         {
-            return self._uid;
+            return self.Id;
         }
 
         /// <inheritdoc />
         public override string ToString()
         {
-            if (IsClientSide())
-            {
-                return $"c{_uid & ~ClientUid}";
-            }
-            return _uid.ToString();
+            return Id.ToString();
         }
 
         public string ToString(string? format, IFormatProvider? formatProvider)
@@ -154,21 +131,13 @@ namespace Robust.Shared.GameObjects
             ReadOnlySpan<char> format,
             IFormatProvider? provider)
         {
-            if (IsClientSide())
-            {
-                return FormatHelpers.TryFormatInto(
-                    destination,
-                    out charsWritten,
-                    $"c{_uid & ~ClientUid}");
-            }
-
-            return _uid.TryFormat(destination, out charsWritten);
+            return Id.TryFormat(destination, out charsWritten);
         }
 
         /// <inheritdoc />
         public int CompareTo(EntityUid other)
         {
-            return _uid.CompareTo(other._uid);
+            return Id.CompareTo(other.Id);
         }
 
         #region ViewVariables

Robust.Shared/GameObjects/IEntityManager.Network.cs

@@ -0,0 +1,194 @@
+using System;
+using System.Collections.Generic;
+using System.Diagnostics.CodeAnalysis;
+using Robust.Shared.Map;
+
+namespace Robust.Shared.GameObjects;
+
+public partial interface IEntityManager
+{
+    /// <summary>
+    /// Tries to parse a string as a NetEntity and return the relevant EntityUid.
+    /// </summary>
+    public bool TryParseNetEntity(string arg, [NotNullWhen(true)] out EntityUid? entity);
+
+    /// <summary>
+    /// TryGet version of <see cref="GetEntity"/>
+    /// </summary>
+    public bool TryGetEntity(NetEntity nEntity, [NotNullWhen(true)] out EntityUid? entity);
+
+    /// <summary>
+    /// TryGet version of <see cref="GetEntity"/>
+    /// </summary>
+    public bool TryGetEntity(NetEntity? nEntity, [NotNullWhen(true)] out EntityUid? entity);
+
+    /// <summary>
+    /// TryGet version of <see cref="GetNetEntity"/>
+    /// </summary>
+    public bool TryGetNetEntity(EntityUid uid, [NotNullWhen(true)] out NetEntity? netEntity, MetaDataComponent? metadata = null);
+
+    /// <summary>
+    /// TryGet version of <see cref="GetNetEntity"/>
+    /// </summary>
+    public bool TryGetNetEntity(EntityUid? uid, [NotNullWhen(true)] out NetEntity? netEntity,
+        MetaDataComponent? metadata = null);
+
+    /// <summary>
+    /// Returns true if the entity only exists on the client.
+    /// </summary>
+    public bool IsClientSide(EntityUid uid, MetaDataComponent? metadata = null);
+
+    /// <summary>
+    /// Tries to get a corresponding <see cref="EntityUid"/> if it exists, otherwise creates an entity for it.
+    /// </summary>
+    /// <param name="nEntity">The net entity we're trying to resolve.</param>
+    /// <param name="T">The type of the component that may need its state handling run later.</param>
+    /// <param name="callerEntity">The entity trying to resolve the net entity. This may be flagged for later component state handling.</param>
+    public EntityUid EnsureEntity<T>(NetEntity nEntity, EntityUid callerEntity);
+
+    /// <summary>
+    /// Tries to get a corresponding <see cref="EntityUid"/> if it exists and nEntity is not null.
+    /// </summary>
+    public EntityUid? EnsureEntity<T>(NetEntity? nEntity, EntityUid callerEntity);
+
+    /// <summary>
+    /// Returns the corresponding local <see cref="EntityUid"/>.
+    /// </summary>
+    public EntityUid GetEntity(NetEntity nEntity);
+
+    /// <summary>
+    /// Returns the corresponding local <see cref="EntityUid"/>.
+    /// </summary>
+    public EntityUid? GetEntity(NetEntity? nEntity);
+
+    /// <summary>
+    /// Returns the corresponding <see cref="NetEntity"/> for the local entity.
+    /// </summary>
+    public NetEntity GetNetEntity(EntityUid uid, MetaDataComponent? metadata = null);
+
+    /// <summary>
+    /// Returns the corresponding <see cref="NetEntity"/> for the local entity.
+    /// </summary>
+    public NetEntity? GetNetEntity(EntityUid? uid, MetaDataComponent? metadata = null);
+
+    /// <summary>
+    /// HashSet version of <see cref="GetEntity"/>
+    /// </summary>
+    public HashSet<EntityUid> GetEntitySet(HashSet<NetEntity> netEntities);
+
+    /// <summary>
+    /// List version of <see cref="GetEntity"/>
+    /// </summary>
+    public List<EntityUid> GetEntityList(List<NetEntity> netEntities);
+
+    /// <summary>
+    /// List version of <see cref="GetEntity"/>
+    /// </summary>
+    public List<EntityUid> GetEntityList(ICollection<NetEntity> netEntities);
+
+    /// <summary>
+    /// List version of <see cref="GetEntity"/>
+    /// </summary>
+    public List<EntityUid?> GetEntityList(List<NetEntity?> netEntities);
+
+    /// <summary>
+    /// List version of <see cref="GetEntity"/>
+    /// </summary>
+    EntityUid[] GetEntityArray(NetEntity[] netEntities);
+
+    /// <summary>
+    /// List version of <see cref="GetEntity"/>
+    /// </summary>
+    EntityUid?[] GetEntityArray(NetEntity?[] netEntities);
+
+    /// <summary>
+    /// HashSet version of <see cref="GetNetEntity"/>
+    /// </summary>
+    public HashSet<NetEntity> GetNetEntitySet(HashSet<EntityUid> entities);
+
+    /// <summary>
+    /// List version of <see cref="GetNetEntity"/>
+    /// </summary>
+    public List<NetEntity> GetNetEntityList(List<EntityUid> entities);
+
+    /// <summary>
+    /// List version of <see cref="GetNetEntity"/>
+    /// </summary>
+    public List<NetEntity> GetNetEntityList(ICollection<EntityUid> entities);
+
+    /// <summary>
+    /// List version of <see cref="GetNetEntity"/>
+    /// </summary>
+    public List<NetEntity?> GetNetEntityList(List<EntityUid?> entities);
+
+    /// <summary>
+    /// List version of <see cref="GetNetEntity"/>
+    /// </summary>
+    NetEntity[] GetNetEntityArray(EntityUid[] entities);
+
+    /// <summary>
+    /// List version of <see cref="GetNetEntity"/>
+    /// </summary>
+    NetEntity?[] GetNetEntityArray(EntityUid?[] entities);
+
+    /// <summary>
+    /// Returns the corresponding <see cref="NetCoordinates"/> for the specified local coordinates.
+    /// </summary>
+    public NetCoordinates GetNetCoordinates(EntityCoordinates coordinates, MetaDataComponent? metadata = null);
+
+    /// <summary>
+    /// Returns the corresponding <see cref="NetCoordinates"/> for the specified local coordinates.
+    /// </summary>
+    public NetCoordinates? GetNetCoordinates(EntityCoordinates? coordinates, MetaDataComponent? metadata = null);
+
+    /// <summary>
+    /// Returns the corresponding <see cref="EntityCoordinates"/> for the specified network coordinates.
+    /// </summary>
+    public EntityCoordinates GetCoordinates(NetCoordinates coordinates);
+
+    /// <summary>
+    /// Returns the corresponding <see cref="EntityCoordinates"/> for the specified network coordinates.
+    /// </summary>
+    public EntityCoordinates? GetCoordinates(NetCoordinates? coordinates);
+
+    /// <summary>
+    /// Tries to get a corresponding <see cref="EntityCoordinates"/> if it exists, otherwise creates an entity for it.
+    /// </summary>
+    /// <param name="netCoordinates">The net coordinates we're trying to resolve.</param>
+    /// <param name="T">The type of the component that may need its state handling run later.</param>
+    /// <param name="callerEntity">The entity trying to resolve the net entity. This may be flagged for later component state handling.</param>
+    public EntityCoordinates EnsureCoordinates<T>(NetCoordinates netCoordinates, EntityUid callerEntity);
+
+    /// <summary>
+    /// Tries to get a corresponding <see cref="EntityCoordinates"/> if it exists and nEntity is not null.
+    /// </summary>
+    public EntityCoordinates? EnsureCoordinates<T>(NetCoordinates? netCoordinates, EntityUid callerEntity);
+
+    public HashSet<EntityCoordinates> GetEntitySet(HashSet<NetCoordinates> netEntities);
+
+    public List<EntityCoordinates> GetEntityList(List<NetCoordinates> netEntities);
+
+    public HashSet<EntityUid> EnsureEntitySet<T>(HashSet<NetEntity> netEntities, EntityUid callerEntity);
+
+    public List<EntityUid> EnsureEntityList<T>(List<NetEntity> netEntities, EntityUid callerEntity);
+
+    public List<EntityCoordinates> GetEntityList(ICollection<NetCoordinates> netEntities);
+
+    public List<EntityCoordinates?> GetEntityList(List<NetCoordinates?> netEntities);
+
+    public EntityCoordinates[] GetEntityArray(NetCoordinates[] netEntities);
+
+    public EntityCoordinates?[] GetEntityArray(NetCoordinates?[] netEntities);
+
+    public HashSet<NetCoordinates> GetNetCoordinatesSet(HashSet<EntityCoordinates> entities);
+
+    public List<NetCoordinates> GetNetCoordinatesList(List<EntityCoordinates> entities);
+
+    public List<NetCoordinates> GetNetCoordinatesList(ICollection<EntityCoordinates> entities);
+
+    public List<NetCoordinates?> GetNetCoordinatesList(List<EntityCoordinates?> entities);
+
+    public NetCoordinates[] GetNetCoordinatesArray(EntityCoordinates[] entities);
+
+    public NetCoordinates?[] GetNetCoordinatesArray(EntityCoordinates?[] entities);
+}

Robust.Shared/GameObjects/IEntityManager.cs

@@ -53,7 +53,7 @@ namespace Robust.Shared.GameObjects
 
         event Action<EntityUid>? EntityAdded;
         event Action<EntityUid>? EntityInitialized;
-        event Action<EntityUid>? EntityDeleted;
+        event Action<EntityUid, MetaDataComponent>? EntityDeleted;
         event Action<EntityUid>? EntityDirtied; // only raised after initialization
 
         EntityUid CreateEntityUninitialized(string? prototypeName, EntityUid euid, ComponentRegistry? overrides = null);

Robust.Shared/GameObjects/NetEntity.cs

@@ -0,0 +1,226 @@
+using System;
+using JetBrains.Annotations;
+using Robust.Shared.IoC;
+using Robust.Shared.Prototypes;
+using Robust.Shared.Serialization;
+using Robust.Shared.Timing;
+using Robust.Shared.ViewVariables;
+
+namespace Robust.Shared.GameObjects;
+
+/// <summary>
+/// Network identifier for entities; used by client and server to refer to the same entity where their local <see cref="EntityUid"/> may differ.
+/// </summary>
+[Serializable, NetSerializable]
+public readonly struct NetEntity : IEquatable<NetEntity>, IComparable<NetEntity>, ISpanFormattable
+{
+    public readonly int Id;
+
+    public const int ClientEntity = 2 << 29;
+
+    /*
+     * Differed to EntityUid to be more consistent with Arch.
+     */
+
+    /// <summary>
+    ///     An Invalid entity UID you can compare against.
+    /// </summary>
+    public static readonly NetEntity Invalid = new(0);
+
+    /// <summary>
+    ///     The first entity UID the entityManager should use when the manager is initialized.
+    /// </summary>
+    public static readonly NetEntity First = new(1);
+
+    /// <summary>
+    ///     Creates an instance of this structure, with the given network ID.
+    /// </summary>
+    public NetEntity(int id)
+    {
+        Id = id;
+    }
+
+    public bool Valid => IsValid();
+
+    /// <summary>
+    ///     Creates a network entity UID by parsing a string number.
+    /// </summary>
+    public static NetEntity Parse(ReadOnlySpan<char> uid)
+    {
+        return new NetEntity(int.Parse(uid));
+    }
+
+    public static bool TryParse(ReadOnlySpan<char> uid, out NetEntity entity)
+    {
+        try
+        {
+            entity = Parse(uid);
+            return true;
+        }
+        catch (FormatException)
+        {
+            entity = Invalid;
+            return false;
+        }
+    }
+
+    /// <summary>
+    ///     Checks if the ID value is valid. Does not check if it identifies
+    ///     a valid Entity.
+    /// </summary>
+    [Pure]
+    public bool IsValid()
+    {
+        return Id > 0;
+    }
+
+    /// <inheritdoc />
+    public bool Equals(NetEntity other)
+    {
+        return Id == other.Id;
+    }
+
+    /// <inheritdoc />
+    public override bool Equals(object? obj)
+    {
+        if (ReferenceEquals(null, obj)) return false;
+        return obj is EntityUid id && Equals(id);
+    }
+
+    /// <inheritdoc />
+    public override int GetHashCode()
+    {
+        return Id;
+    }
+
+    /// <summary>
+    ///     Check for equality by value between two objects.
+    /// </summary>
+    public static bool operator ==(NetEntity a, NetEntity b)
+    {
+        return a.Id == b.Id;
+    }
+
+    /// <summary>
+    ///     Check for inequality by value between two objects.
+    /// </summary>
+    public static bool operator !=(NetEntity a, NetEntity b)
+    {
+        return !(a == b);
+    }
+
+    /// <summary>
+    ///     Explicit conversion of EntityId to int. This should only be used in special
+    ///     cases like serialization. Do NOT use this in content.
+    /// </summary>
+    public static explicit operator int(NetEntity self)
+    {
+        return self.Id;
+    }
+
+    /// <inheritdoc />
+    public override string ToString()
+    {
+        return Id.ToString();
+    }
+
+    public string ToString(string? format, IFormatProvider? formatProvider)
+    {
+        return ToString();
+    }
+
+    public bool TryFormat(
+        Span<char> destination,
+        out int charsWritten,
+        ReadOnlySpan<char> format,
+        IFormatProvider? provider)
+    {
+        return Id.TryFormat(destination, out charsWritten);
+    }
+
+    /// <inheritdoc />
+    public int CompareTo(NetEntity other)
+    {
+        return Id.CompareTo(other.Id);
+    }
+
+    public bool IsClientSide() => (Id & ClientEntity) == ClientEntity;
+
+    #region ViewVariables
+
+
+    [ViewVariables]
+    private string Representation
+    {
+        get
+        {
+            var entManager = IoCManager.Resolve<IEntityManager>();
+            return entManager.ToPrettyString(entManager.GetEntity(this));
+        }
+    }
+
+    [ViewVariables(VVAccess.ReadWrite)]
+    private string Name
+    {
+        get => MetaData?.EntityName ?? string.Empty;
+        set
+        {
+            if (MetaData is {} metaData)
+                metaData.EntityName = value;
+        }
+    }
+
+    [ViewVariables(VVAccess.ReadWrite)]
+    private string Description
+    {
+        get => MetaData?.EntityDescription ?? string.Empty;
+        set
+        {
+            if (MetaData is {} metaData)
+                metaData.EntityDescription = value;
+        }
+    }
+
+    [ViewVariables]
+    private EntityPrototype? Prototype => MetaData?.EntityPrototype;
+
+    [ViewVariables]
+    private GameTick LastModifiedTick => MetaData?.EntityLastModifiedTick ?? GameTick.Zero;
+
+    [ViewVariables]
+    private bool Paused => MetaData?.EntityPaused ?? false;
+
+    [ViewVariables]
+    private EntityLifeStage LifeStage => MetaData?.EntityLifeStage ?? EntityLifeStage.Deleted;
+
+    [ViewVariables]
+    private MetaDataComponent? MetaData
+    {
+        get
+        {
+            var entManager = IoCManager.Resolve<IEntityManager>();
+            return entManager.GetComponentOrNull<MetaDataComponent>(entManager.GetEntity(this));
+        }
+    }
+
+    [ViewVariables]
+    private TransformComponent? Transform
+    {
+        get
+        {
+            var entManager = IoCManager.Resolve<IEntityManager>();
+            return entManager.GetComponentOrNull<TransformComponent>(entManager.GetEntity(this));
+        }
+    }
+
+    [ViewVariables]
+    private EntityUid Uid
+    {
+        get
+        {
+            return IoCManager.Resolve<IEntityManager>().GetEntity(this);
+        }
+    }
+
+    #endregion
+}

Robust.Shared/GameObjects/Systems/SharedGridFixtureSystem.cs

@@ -230,7 +230,7 @@ namespace Robust.Shared.GameObjects
     [Serializable, NetSerializable]
     public sealed class ChunkSplitDebugMessage : EntityEventArgs
     {
-        public EntityUid Grid;
+        public NetEntity Grid;
         public Dictionary<Vector2i, List<List<Vector2i>>> Nodes = new ();
         public List<(Vector2 Start, Vector2 End)> Connections = new();
     }

Robust.Shared/GameObjects/Systems/SharedTransformSystem.Component.cs

@@ -480,7 +480,7 @@ public abstract partial class SharedTransformSystem
             if (value.EntityId == uid)
             {
                 DetachParentToNull(uid, xform);
-                if (_netMan.IsServer || uid.IsClientSide())
+                if (_netMan.IsServer || IsClientSide(uid))
                     QueueDel(uid);
                 throw new InvalidOperationException($"Attempted to parent an entity to itself: {ToPrettyString(uid)}");
             }
@@ -490,7 +490,7 @@ public abstract partial class SharedTransformSystem
                 if (!_xformQuery.Resolve(value.EntityId, ref newParent, false))
                 {
                     DetachParentToNull(uid, xform);
-                    if (_netMan.IsServer || uid.IsClientSide())
+                    if (_netMan.IsServer || IsClientSide(uid))
                         QueueDel(uid);
                     throw new InvalidOperationException($"Attempted to parent entity {ToPrettyString(uid)} to non-existent entity {value.EntityId}");
                 }
@@ -498,7 +498,7 @@ public abstract partial class SharedTransformSystem
                 if (newParent.LifeStage > ComponentLifeStage.Running || LifeStage(value.EntityId) > EntityLifeStage.MapInitialized)
                 {
                     DetachParentToNull(uid, xform);
-                    if (_netMan.IsServer || uid.IsClientSide())
+                    if (_netMan.IsServer || IsClientSide(uid))
                         QueueDel(uid);
                     throw new InvalidOperationException($"Attempted to re-parent to a terminating object. Entity: {ToPrettyString(uid)}, new parent: {ToPrettyString(value.EntityId)}");
                 }
@@ -625,7 +625,7 @@ public abstract partial class SharedTransformSystem
 
     public TransformComponent? GetParent(TransformComponent xform)
     {
-        if (!xform.ParentUid.IsValid()) 
+        if (!xform.ParentUid.IsValid())
             return null;
         return _xformQuery.GetComponent(xform.ParentUid);
     }
@@ -678,10 +678,12 @@ public abstract partial class SharedTransformSystem
     internal void OnGetState(EntityUid uid, TransformComponent component, ref ComponentGetState args)
     {
         DebugTools.Assert(!component.ParentUid.IsValid() || (!Deleted(component.ParentUid) && !EntityManager.IsQueuedForDeletion(component.ParentUid)));
+        var parent = GetNetEntity(component.ParentUid);
+
         args.State = new TransformComponentState(
             component.LocalPosition,
             component.LocalRotation,
-            component.ParentUid,
+            parent,
             component.NoLocalRotation,
             component.Anchored);
     }
@@ -690,13 +692,16 @@ public abstract partial class SharedTransformSystem
     {
         if (args.Current is TransformComponentState newState)
         {
-            var newParentId = newState.ParentID;
+            var parent = GetEntity(newState.ParentID);
+            if (!parent.IsValid() && newState.ParentID.IsValid())
+                Log.Error($"Received transform component state with an unknown parent Id. Entity: {ToPrettyString(uid)}. Net parent: {newState.ParentID}");
+
             var oldAnchored = xform.Anchored;
 
             // update actual position data, if required
             if (!xform.LocalPosition.EqualsApprox(newState.LocalPosition)
                 || !xform.LocalRotation.EqualsApprox(newState.Rotation)
-                || xform.ParentUid != newParentId)
+                || xform.ParentUid != parent)
             {
                 // remove from any old grid lookups
                 if (xform.Anchored && TryComp(xform.ParentUid, out MapGridComponent? grid))
@@ -709,7 +714,7 @@ public abstract partial class SharedTransformSystem
                 xform._anchored |= newState.Anchored;
 
                 // Update the action position, rotation, and parent (and hence also map, grid, etc).
-                SetCoordinates(uid, xform, new EntityCoordinates(newParentId, newState.LocalPosition), newState.Rotation, unanchor: false);
+                SetCoordinates(uid, xform, new EntityCoordinates(parent, newState.LocalPosition), newState.Rotation, unanchor: false);
 
                 xform._anchored = newState.Anchored;
 
@@ -744,7 +749,7 @@ public abstract partial class SharedTransformSystem
             xform.PrevRotation = newState.Rotation;
             xform._noLocalRotation = newState.NoLocalRotation;
 
-            DebugTools.Assert(xform.ParentUid == newState.ParentID, "Transform state failed to set parent");
+            DebugTools.Assert(xform.ParentUid == parent, "Transform state failed to set parent");
             DebugTools.Assert(xform.Anchored == newState.Anchored, "Transform state failed to set anchored");
         }
 
@@ -752,7 +757,7 @@ public abstract partial class SharedTransformSystem
         {
             xform.NextPosition = nextTransform.LocalPosition;
             xform.NextRotation = nextTransform.Rotation;
-            xform.LerpParent = nextTransform.ParentID;
+            xform.LerpParent = GetEntity(nextTransform.ParentID);
             ActivateLerp(xform);
         }
         else
@@ -1375,12 +1380,12 @@ public abstract partial class SharedTransformSystem
     /// Attempts to place one entity next to another entity. If the target entity is in a container, this will attempt
     /// to insert that entity into the same container.
     /// </summary>
-    public void PlaceNextToOrDrop(EntityUid uid, EntityUid target, 
+    public void PlaceNextToOrDrop(EntityUid uid, EntityUid target,
         TransformComponent? xform = null, TransformComponent? targetXform = null)
     {
         if (!_xformQuery.Resolve(target, ref targetXform))
             return;
-        
+
         if (!_xformQuery.Resolve(uid, ref xform))
             return;
 

Robust.Shared/GameObjects/Systems/SharedTransformSystem.cs

@@ -281,7 +281,7 @@ namespace Robust.Shared.GameObjects
         /// <summary>
         ///     Current parent entity of this entity.
         /// </summary>
-        public readonly EntityUid ParentID;
+        public readonly NetEntity ParentID;
 
         /// <summary>
         ///     Current position offset of the entity.
@@ -310,7 +310,7 @@ namespace Robust.Shared.GameObjects
         /// <param name="rotation">Current direction offset of this entity.</param>
         /// <param name="parentId">Current parent transform of this entity.</param>
         /// <param name="noLocalRotation"></param>
-        public TransformComponentState(Vector2 localPosition, Angle rotation, EntityUid parentId, bool noLocalRotation, bool anchored)
+        public TransformComponentState(Vector2 localPosition, Angle rotation, NetEntity parentId, bool noLocalRotation, bool anchored)
         {
             LocalPosition = localPosition;
             Rotation = rotation;

Robust.Shared/GameStates/GameState.cs

@@ -26,7 +26,7 @@ namespace Robust.Shared.GameStates
             uint lastInput,
             NetListAsArray<EntityState> entities,
             NetListAsArray<PlayerState> players,
-            NetListAsArray<EntityUid> deletions)
+            NetListAsArray<NetEntity> deletions)
         {
             FromSequence = fromSequence;
             ToSequence = toSequence;
@@ -43,6 +43,6 @@ namespace Robust.Shared.GameStates
 
         public readonly NetListAsArray<EntityState> EntityStates;
         public readonly NetListAsArray<PlayerState> PlayerStates;
-        public readonly NetListAsArray<EntityUid> EntityDeletions;
+        public readonly NetListAsArray<NetEntity> EntityDeletions;
     }
 }

Robust.Shared/GameStates/PlayerState.cs

@@ -17,7 +17,7 @@ namespace Robust.Shared.GameStates
         public SessionStatus Status { get; set; }
         public short Ping { get; set; }
 
-        public EntityUid? ControlledEntity { get; set; }
+        public NetEntity? ControlledEntity { get; set; }
 
         public PlayerState Clone()
         {

Robust.Shared/Input/Binding/InputCmdHandler.cs

@@ -1,4 +1,5 @@
-using Robust.Shared.GameObjects;
+using System;
+using Robust.Shared.GameObjects;
 using Robust.Shared.Map;
 using Robust.Shared.Players;
 
@@ -18,7 +19,7 @@ namespace Robust.Shared.Input.Binding
         {
         }
 
-        public abstract bool HandleCmdMessage(ICommonSession? session, InputCmdMessage message);
+        public abstract bool HandleCmdMessage(IEntityManager entManager, ICommonSession? session, IFullInputCmdMessage message);
 
         /// <summary>
         ///     Makes a quick input command from enabled and disabled delegates.
@@ -56,12 +57,9 @@ namespace Robust.Shared.Input.Binding
                 DisabledDelegate?.Invoke(session);
             }
 
-            public override bool HandleCmdMessage(ICommonSession? session, InputCmdMessage message)
+            public override bool HandleCmdMessage(IEntityManager entManager, ICommonSession? session, IFullInputCmdMessage message)
             {
-                if (!(message is FullInputCmdMessage msg))
-                    return false;
-
-                switch (msg.State)
+                switch (message.State)
                 {
                     case BoundKeyState.Up:
                         Disabled(session);
@@ -111,14 +109,28 @@ namespace Robust.Shared.Input.Binding
             FireOutsidePrediction = outsidePrediction;
         }
 
-        public override bool HandleCmdMessage(ICommonSession? session, InputCmdMessage message)
+        public override bool HandleCmdMessage(IEntityManager entManager, ICommonSession? session, IFullInputCmdMessage message)
         {
-            if (!(message is FullInputCmdMessage msg) || (_ignoreUp && msg.State != BoundKeyState.Down))
+            if ((_ignoreUp && message.State != BoundKeyState.Down))
                 return false;
 
-            var handled = _callback?.Invoke(new PointerInputCmdArgs(session, msg.Coordinates,
-                msg.ScreenCoordinates, msg.Uid, msg.State, msg));
-            return handled.HasValue && handled.Value;
+            switch (message)
+            {
+                case ClientFullInputCmdMessage clientInput:
+                {
+                    var handled = _callback?.Invoke(new PointerInputCmdArgs(session, clientInput.Coordinates,
+                        clientInput.ScreenCoordinates, clientInput.Uid, message.State, message));
+                    return handled.HasValue && handled.Value;
+                }
+                case FullInputCmdMessage fullInput:
+                {
+                    var handled = _callback?.Invoke(new PointerInputCmdArgs(session, entManager.GetCoordinates(fullInput.Coordinates),
+                        fullInput.ScreenCoordinates, entManager.GetEntity(fullInput.Uid), fullInput.State, message));
+                    return handled.HasValue && handled.Value;
+                }
+                default:
+                    throw new ArgumentOutOfRangeException();
+            }
         }
 
         public readonly struct PointerInputCmdArgs
@@ -128,11 +140,11 @@ namespace Robust.Shared.Input.Binding
             public readonly ScreenCoordinates ScreenCoordinates;
             public readonly EntityUid EntityUid;
             public readonly BoundKeyState State;
-            public readonly FullInputCmdMessage OriginalMessage;
+            public readonly IFullInputCmdMessage OriginalMessage;
 
             public PointerInputCmdArgs(ICommonSession? session, EntityCoordinates coordinates,
                 ScreenCoordinates screenCoordinates, EntityUid entityUid, BoundKeyState state,
-                FullInputCmdMessage originalMessage)
+                IFullInputCmdMessage originalMessage)
             {
                 Session = session;
                 Coordinates = coordinates;
@@ -158,17 +170,28 @@ namespace Robust.Shared.Input.Binding
         }
 
         /// <inheritdoc />
-        public override bool HandleCmdMessage(ICommonSession? session, InputCmdMessage message)
+        public override bool HandleCmdMessage(IEntityManager entManager, ICommonSession? session, IFullInputCmdMessage message)
         {
-            if (!(message is FullInputCmdMessage msg))
-                return false;
-
-            switch (msg.State)
+            switch (message)
             {
-                case BoundKeyState.Up:
-                    return _disabled?.Invoke(session, msg.Coordinates, msg.Uid) == true;
-                case BoundKeyState.Down:
-                    return _enabled?.Invoke(session, msg.Coordinates, msg.Uid) == true;
+                case ClientFullInputCmdMessage clientInput:
+                    switch (clientInput.State)
+                    {
+                        case BoundKeyState.Up:
+                            return _disabled?.Invoke(session, clientInput.Coordinates, clientInput.Uid) == true;
+                        case BoundKeyState.Down:
+                            return _enabled?.Invoke(session, clientInput.Coordinates, clientInput.Uid) == true;
+                    }
+                    break;
+                case FullInputCmdMessage fullInput:
+                    switch (fullInput.State)
+                    {
+                        case BoundKeyState.Up:
+                            return _disabled?.Invoke(session, entManager.GetCoordinates(fullInput.Coordinates), entManager.GetEntity(fullInput.Uid)) == true;
+                        case BoundKeyState.Down:
+                            return _enabled?.Invoke(session, entManager.GetCoordinates(fullInput.Coordinates), entManager.GetEntity(fullInput.Uid)) == true;
+                    }
+                    break;
             }
 
             //Client Sanitization: unknown key state, just ignore
@@ -183,7 +206,7 @@ namespace Robust.Shared.Input.Binding
     public sealed class NullInputCmdHandler : InputCmdHandler
     {
         /// <inheritdoc />
-        public override bool HandleCmdMessage(ICommonSession? session, InputCmdMessage message)
+        public override bool HandleCmdMessage(IEntityManager entManager, ICommonSession? session, IFullInputCmdMessage message)
         {
             return true;
         }

Robust.Shared/Input/InputCmdMessage.cs

@@ -113,12 +113,12 @@ namespace Robust.Shared.Input
         /// <summary>
         ///     Local Coordinates of the pointer when the command was created.
         /// </summary>
-        public EntityCoordinates Coordinates { get; }
+        public NetCoordinates Coordinates { get; }
 
         /// <summary>
         ///     Entity that was under the pointer when the command was created (if any).
         /// </summary>
-        public EntityUid Uid { get; }
+        public NetEntity Uid { get; }
 
         /// <summary>
         ///     Creates an instance of <see cref="PointerInputCmdMessage"/>.
@@ -126,8 +126,8 @@ namespace Robust.Shared.Input
         /// <param name="tick">Client tick this was created.</param>
         /// <param name="inputFunctionId">Function this command is changing.</param>
         /// <param name="coordinates">Local Coordinates of the pointer when the command was created.</param>
-        public PointerInputCmdMessage(GameTick tick, ushort subTick, KeyFunctionId inputFunctionId, EntityCoordinates coordinates)
-            : this(tick, subTick, inputFunctionId, coordinates, EntityUid.Invalid) { }
+        public PointerInputCmdMessage(GameTick tick, ushort subTick, KeyFunctionId inputFunctionId, NetCoordinates coordinates)
+            : this(tick, subTick, inputFunctionId, coordinates, NetEntity.Invalid) { }
 
         /// <summary>
         ///     Creates an instance of <see cref="PointerInputCmdMessage"/> with an optional Entity reference.
@@ -136,7 +136,7 @@ namespace Robust.Shared.Input
         /// <param name="inputFunctionId">Function this command is changing.</param>
         /// <param name="coordinates">Local Coordinates of the pointer when the command was created.</param>
         /// <param name="uid">Entity that was under the pointer when the command was created.</param>
-        public PointerInputCmdMessage(GameTick tick, ushort subTick, KeyFunctionId inputFunctionId, EntityCoordinates coordinates, EntityUid uid)
+        public PointerInputCmdMessage(GameTick tick, ushort subTick, KeyFunctionId inputFunctionId, NetCoordinates coordinates, NetEntity uid)
             : base(tick, subTick, inputFunctionId)
         {
             Coordinates = coordinates;
@@ -144,11 +144,51 @@ namespace Robust.Shared.Input
         }
     }
 
+    /// <summary>
+    /// Handles inputs clientside. This is used so the client can still interact with client-only entities without relying on
+    /// <see cref="NetEntity"/>.
+    /// </summary>
+    public sealed class ClientFullInputCmdMessage : InputCmdMessage, IFullInputCmdMessage
+    {
+        /// <summary>
+        ///     New state of the Input Function.
+        /// </summary>
+        public BoundKeyState State { get; init; }
+
+        /// <summary>
+        ///     Local Coordinates of the pointer when the command was created.
+        /// </summary>
+        public EntityCoordinates Coordinates { get; init; }
+
+        /// <summary>
+        ///     Screen Coordinates of the pointer when the command was created.
+        /// </summary>
+        public ScreenCoordinates ScreenCoordinates { get; init; }
+
+        /// <summary>
+        ///     Entity that was under the pointer when the command was created (if any).
+        /// </summary>
+        public EntityUid Uid { get; init; }
+
+        public ClientFullInputCmdMessage(GameTick tick, ushort subTick, KeyFunctionId inputFunctionId) : base(tick, subTick, inputFunctionId)
+        {
+        }
+    }
+
+    public interface IFullInputCmdMessage
+    {
+        GameTick Tick { get; }
+        BoundKeyState State { get; }
+        KeyFunctionId InputFunctionId { get; }
+        ushort SubTick { get; }
+        uint InputSequence { get; set; }
+    }
+
     /// <summary>
     ///     An input command that has both state and pointer info.
     /// </summary>
     [Serializable, NetSerializable]
-    public sealed class FullInputCmdMessage : InputCmdMessage
+    public sealed class FullInputCmdMessage : InputCmdMessage, IFullInputCmdMessage
     {
         /// <summary>
         ///     New state of the Input Function.
@@ -158,7 +198,7 @@ namespace Robust.Shared.Input
         /// <summary>
         ///     Local Coordinates of the pointer when the command was created.
         /// </summary>
-        public EntityCoordinates Coordinates { get; }
+        public NetCoordinates Coordinates { get; }
 
         /// <summary>
         ///     Screen Coordinates of the pointer when the command was created.
@@ -168,7 +208,7 @@ namespace Robust.Shared.Input
         /// <summary>
         ///     Entity that was under the pointer when the command was created (if any).
         /// </summary>
-        public EntityUid Uid { get; }
+        public NetEntity Uid { get; init; }
 
         /// <summary>
         ///     Creates an instance of <see cref="FullInputCmdMessage"/>.
@@ -179,8 +219,8 @@ namespace Robust.Shared.Input
         /// <param name="state">New state of the Input Function.</param>
         /// <param name="coordinates">Local Coordinates of the pointer when the command was created.</param>
         /// <param name="screenCoordinates"></param>
-        public FullInputCmdMessage(GameTick tick, ushort subTick, int inputSequence, KeyFunctionId inputFunctionId, BoundKeyState state, EntityCoordinates coordinates, ScreenCoordinates screenCoordinates)
-            : this(tick, subTick, inputFunctionId, state, coordinates, screenCoordinates, EntityUid.Invalid) { }
+        public FullInputCmdMessage(GameTick tick, ushort subTick, int inputSequence, KeyFunctionId inputFunctionId, BoundKeyState state, NetCoordinates coordinates, ScreenCoordinates screenCoordinates)
+            : this(tick, subTick, inputFunctionId, state, coordinates, screenCoordinates, NetEntity.Invalid) { }
 
         /// <summary>
         ///     Creates an instance of <see cref="FullInputCmdMessage"/> with an optional Entity reference.
@@ -191,7 +231,7 @@ namespace Robust.Shared.Input
         /// <param name="coordinates">Local Coordinates of the pointer when the command was created.</param>
         /// <param name="screenCoordinates"></param>
         /// <param name="uid">Entity that was under the pointer when the command was created.</param>
-        public FullInputCmdMessage(GameTick tick, ushort subTick, KeyFunctionId inputFunctionId, BoundKeyState state, EntityCoordinates coordinates, ScreenCoordinates screenCoordinates, EntityUid uid)
+        public FullInputCmdMessage(GameTick tick, ushort subTick, KeyFunctionId inputFunctionId, BoundKeyState state, NetCoordinates coordinates, ScreenCoordinates screenCoordinates, NetEntity uid)
             : base(tick, subTick, inputFunctionId)
         {
             State = state;

Robust.Shared/Map/EntityCoordinates.cs

@@ -13,7 +13,6 @@ namespace Robust.Shared.Map
     ///     A set of coordinates relative to another entity.
     /// </summary>
     [PublicAPI]
-    [Serializable, NetSerializable]
     public readonly struct EntityCoordinates : IEquatable<EntityCoordinates>, ISpanFormattable
     {
         public static readonly EntityCoordinates Invalid = new(EntityUid.Invalid, Vector2.Zero);

Robust.Shared/Map/NetCoordinates.cs

@@ -0,0 +1,102 @@
+using System;
+using System.Numerics;
+using JetBrains.Annotations;
+using Robust.Shared.GameObjects;
+using Robust.Shared.Serialization;
+using Robust.Shared.Utility;
+
+namespace Robust.Shared.Map;
+
+/// <summary>
+///     A networked version of <see cref="EntityCoordinates"/>
+/// </summary>
+[PublicAPI]
+[Serializable, NetSerializable]
+public readonly struct NetCoordinates : IEquatable<NetCoordinates>, ISpanFormattable
+{
+    public static readonly NetCoordinates Invalid = new(NetEntity.Invalid, Vector2.Zero);
+
+    /// <summary>
+    ///     Networked ID of the entity that this position is relative to.
+    /// </summary>
+    public readonly NetEntity NetEntity;
+
+    /// <summary>
+    ///     Position in the entity's local space.
+    /// </summary>
+    public readonly Vector2 Position;
+
+    /// <summary>
+    ///     Location of the X axis local to the entity.
+    /// </summary>
+    public float X => Position.X;
+
+    /// <summary>
+    ///     Location of the Y axis local to the entity.
+    /// </summary>
+    public float Y => Position.Y;
+
+    public NetCoordinates(NetEntity netEntity, Vector2 position)
+    {
+        NetEntity = netEntity;
+        Position = position;
+    }
+
+    public NetCoordinates(NetEntity netEntity, float x, float y)
+    {
+        NetEntity = netEntity;
+        Position = new Vector2(x, y);
+    }
+    #region IEquatable
+
+    /// <inheritdoc />
+    public bool Equals(NetCoordinates other)
+    {
+        return NetEntity.Equals(other.NetEntity) && Position.Equals(other.Position);
+    }
+
+    /// <inheritdoc />
+    public override bool Equals(object? obj)
+    {
+        return obj is NetCoordinates other && Equals(other);
+    }
+
+    /// <inheritdoc />
+    public override int GetHashCode()
+    {
+        return HashCode.Combine(NetEntity, Position);
+    }
+
+    #endregion
+
+    /// <summary>
+    /// Deconstructs the object into it's fields.
+    /// </summary>
+    /// <param name="entId">ID of the entity that this position is relative to.</param>
+    /// <param name="localPos">Position in the entity's local space.</param>
+    public void Deconstruct(out NetEntity entId, out Vector2 localPos)
+    {
+        entId = NetEntity;
+        localPos = Position;
+    }
+
+    /// <inheritdoc />
+    public override string ToString()
+    {
+        return $"NetEntity={NetEntity}, X={Position.X:N2}, Y={Position.Y:N2}";
+    }
+
+    public string ToString(string? format, IFormatProvider? formatProvider) => ToString();
+
+    public bool TryFormat(
+        Span<char> destination,
+        out int charsWritten,
+        ReadOnlySpan<char> format,
+        IFormatProvider? provider)
+    {
+        return FormatHelpers.TryFormatInto(
+            destination,
+            out charsWritten,
+            $"NetEntity={NetEntity}, X={Position.X:N2}, Y={Position.Y:N2}");
+    }
+}