Version: 162.0.0

Co-authored-by: ElectroJr <leonsfriedrich@gmail.com>

MSBuild/Robust.Engine.Version.props

@@ -1,4 +1,4 @@
 <Project>
 
-    <!-- This file automatically reset by Tools/version.py -->
+    <!-- This file automatically reset by Tools/version.py -->
 

RELEASE-NOTES.md

@@ -54,6 +54,90 @@ END TEMPLATE-->
 *None yet*
 
 
+## 162.0.0
+
+### New features
+
+* Add entity categories for prototypes and deprecate the `noSpawn` tag.
+* Add missing proxy method for `TryGetEntityData`.
+* Add NetForceAckThreshold cvar to forcibly update acks for late clients.
+
+### Internal
+
+* Use CollectionMarshals in PVS and DynamicTree.
+* Make the proxy methods use MetaQuery / TransformQuery.
+
+
+## 161.1.0
+
+### New features
+
+* Add more DebugTools assert variations.
+
+### Bugfixes
+
+* Don't attempt to insert entities into deleted containers.
+* Try to fix oldestAck not being set correctly leading to deletion history getting bloated for pvs.
+
+
+## 161.0.0
+
+### Breaking changes
+
+* Point light animations now need to use different component fields in order to animate the lights. `Enabled` should be replaced with `AnimatedEnable` and `Radius` should be replaced with `AnimatedRadius`
+
+### New features
+
+* EntProtoId is now net-serializable
+* Added print_pvs_ack command to debug PVS issues.
+
+### Bugfixes
+
+* Fixes AngleTypeParser not using InvariantCulture
+* Fixed a bug that was causing `MetaDataComponent.LastComponentRemoved` to be updated improperly.
+
+### Other
+
+* The string representation of client-side entities now looks nicer and simply uses a 'c' prefix.
+
+
+## 160.1.0
+
+### New features
+
+* Add optional MetaDataComponent args to Entitymanager methods.
+
+### Internal
+
+* Move _netComponents onto MetaDataComponent.
+* Remove some component resolves internally on adding / removing components.
+
+
+## 160.0.2
+
+### Other
+
+* Transform component and containers have new convenience fields to make using VIewVariables easier.
+
+
+## 160.0.0
+
+### Breaking changes
+
+* ComponentReference has now been entirely removed.
+* Sensor / non-hard physics bodies are now included in EntityLookup by default.
+
+
+## 159.1.0
+
+
+## 159.0.3
+
+### Bugfixes
+
+* Fix potentially deleted entities having states re-applied when NetEntities come in.
+
+
 ## 159.0.2
 
 ### Bugfixes

Resources/EnginePrototypes/Debug/rotation.yml

@@ -1,7 +1,7 @@
 - type: entity
   id: debugRotation
   abstract: true
-  suffix: DEBUG
+  categories: [ debug ]
   components:
   - type: Sprite
     netsync: false

Resources/EnginePrototypes/entityCategory.yml

@@ -0,0 +1,17 @@
+# debug related entities
+- type: entityCategory
+  id: debug
+  name: entity-category-name-debug
+  description: entity-category-desc-debug
+
+# entities that spawn other entities
+- type: entityCategory
+  id: spawner
+  name: entity-category-name-spawner
+  description: entity-category-desc-spawner
+
+# entities that should be hidden from the spawn menu
+- type: entityCategory
+  id: hideSpawnMenu
+  name: entity-category-name-hide
+  description: entity-category-desc-hide

Resources/Locale/en-US/entity-category.ftl

@@ -0,0 +1,8 @@
+entity-category-name-debug = Debug
+entity-category-desc-debug = Entity prototypes intended for debugging & testing.
+
+entity-category-name-spawner = Spawner
+entity-category-desc-spawner = Entity prototypes that spawn other entities.
+
+entity-category-name-hide = Hidden
+entity-category-desc-hide = Entity prototypes that should be hidden from the spawn menu

Robust.Client/Console/Commands/Debug.cs

@@ -78,14 +78,7 @@ namespace Robust.Client.Console.Commands
                     message.Append($"net ID: {registration.NetID}");
                 }
 
-                message.Append($", References:");
-
                 shell.WriteLine(message.ToString());
-
-                foreach (var type in registration.References)
-                {
-                    shell.WriteLine($"  {type}");
-                }
             }
             catch (UnknownComponentException)
             {

Robust.Client/GameObjects/ClientEntityManager.Network.cs

@@ -35,14 +35,14 @@ public sealed partial class ClientEntityManager
 
         if (NetEntityLookup.TryGetValue(nEntity, out var entity))
         {
-            return entity;
+            return entity.Item1;
         }
 
         // Flag the callerEntity to have their state potentially re-run later.
         var pending = PendingNetEntityStates.GetOrNew(nEntity);
         pending.Add((typeof(T), callerEntity));
 
-        return entity;
+        return entity.Item1;
     }
 
     public override EntityCoordinates EnsureCoordinates<T>(NetCoordinates netCoordinates, EntityUid callerEntity)

Robust.Client/GameObjects/ClientEntityManager.cs

@@ -1,5 +1,6 @@
 using System;
 using System.Collections.Generic;
+using System.Diagnostics.CodeAnalysis;
 using Prometheus;
 using Robust.Client.GameStates;
 using Robust.Client.Player;
@@ -65,9 +66,12 @@ namespace Robust.Client.GameObjects
                 base.DirtyEntity(uid, meta);
         }
 
-        public override void QueueDeleteEntity(EntityUid uid)
+        public override void QueueDeleteEntity(EntityUid? uid)
         {
-            if (IsClientSide(uid))
+            if (uid == null)
+                return;
+
+            if (IsClientSide(uid.Value))
             {
                 base.QueueDeleteEntity(uid);
                 return;
@@ -78,7 +82,7 @@ namespace Robust.Client.GameObjects
 
             // Client-side entity deletion is not supported and will cause errors.
             if (_client.RunLevel == ClientRunLevel.Connected || _client.RunLevel == ClientRunLevel.InGame)
-                LogManager.RootSawmill.Error($"Predicting the queued deletion of a networked entity: {ToPrettyString(uid)}. Trace: {Environment.StackTrace}");
+                LogManager.RootSawmill.Error($"Predicting the queued deletion of a networked entity: {ToPrettyString(uid.Value)}. Trace: {Environment.StackTrace}");
         }
 
         /// <inheritdoc />
@@ -89,12 +93,16 @@ namespace Robust.Client.GameObjects
                 base.Dirty(uid, component, meta);
         }
 
-        public override EntityStringRepresentation ToPrettyString(EntityUid uid)
+        [return: NotNullIfNotNull("uid")]
+        public override EntityStringRepresentation? ToPrettyString(EntityUid? uid)
         {
+            if (uid == null)
+                return null;
+
             if (_playerManager.LocalPlayer?.ControlledEntity == uid)
-                return base.ToPrettyString(uid) with { Session = _playerManager.LocalPlayer.Session };
-            else
-                return base.ToPrettyString(uid);
+                return base.ToPrettyString(uid).Value with { Session = _playerManager.LocalPlayer.Session };
+
+            return base.ToPrettyString(uid);
         }
 
         public override void RaisePredictiveEvent<T>(T msg)

Robust.Client/GameObjects/EntitySystems/EyeSystem.cs

@@ -17,12 +17,18 @@ public sealed class EyeSystem : SharedEyeSystem
         SubscribeLocalEvent<EyeComponent, ComponentInit>(OnInit);
         SubscribeLocalEvent<EyeComponent, PlayerDetachedEvent>(OnEyeDetached);
         SubscribeLocalEvent<EyeComponent, PlayerAttachedEvent>(OnEyeAttached);
+        SubscribeLocalEvent<EyeComponent, AfterAutoHandleStateEvent>(OnEyeAutoState);
 
         // Make sure this runs *after* entities have been moved by interpolation and movement.
         UpdatesAfter.Add(typeof(TransformSystem));
         UpdatesAfter.Add(typeof(PhysicsSystem));
     }
 
+    private void OnEyeAutoState(EntityUid uid, EyeComponent component, ref AfterAutoHandleStateEvent args)
+    {
+        UpdateEye(component);
+    }
+
     private void OnEyeAttached(EntityUid uid, EyeComponent component, PlayerAttachedEvent args)
     {
         // TODO: This probably shouldn't be nullable bruv.

Robust.Client/GameObjects/EntitySystems/PointLightSystem.cs

@@ -25,13 +25,15 @@ namespace Robust.Client.GameObjects
             if (args.Current is not PointLightComponentState state)
                 return;
 
-            SetEnabled(uid, state.Enabled, component);
+            component.Enabled = state.Enabled;
             component.Offset = state.Offset;
             component.Softness = state.Softness;
             component.CastShadows = state.CastShadows;
             component.Energy = state.Energy;
             component.Radius = state.Radius;
             component.Color = state.Color;
+
+            _lightTree.QueueTreeUpdate(uid, component);
         }
 
         public override SharedPointLightComponent EnsureLight(EntityUid uid)

Robust.Client/GameStates/ClientDirtySystem.cs

@@ -1,7 +1,6 @@
 using Robust.Client.Timing;
 using Robust.Shared.GameObjects;
 using Robust.Shared.IoC;
-using Robust.Shared.Log;
 using Robust.Shared.Utility;
 using System;
 using System.Collections.Generic;
@@ -54,7 +53,7 @@ public sealed class ClientDirtySystem : EntitySystem
 
         var uid = args.BaseArgs.Owner;
         var comp = args.BaseArgs.Component;
-        if (!_timing.InPrediction || !comp.NetSyncEnabled || IsClientSide(uid))
+        if (!_timing.InPrediction || !comp.NetSyncEnabled || IsClientSide(uid, args.Meta))
             return;
 
         // Was this component added during prediction? If yes, then there is no need to re-add it when resetting.

Robust.Client/GameStates/ClientGameStateManager.cs

@@ -47,7 +47,7 @@ namespace Robust.Client.GameStates
                 = new();
 
         // Game state dictionaries that get used every tick.
-        private readonly Dictionary<EntityUid, (NetEntity NetEntity, bool EnteringPvs, GameTick LastApplied, EntityState? curState, EntityState? nextState)> _toApply = new();
+        private readonly Dictionary<EntityUid, (NetEntity NetEntity, MetaDataComponent Meta, 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();
@@ -497,11 +497,7 @@ namespace Robust.Client.GameStates
 
                 countReset += 1;
 
-                var netComps = _entityManager.GetNetComponentsOrNull(entity);
-                if (netComps == null)
-                    continue;
-
-                foreach (var (netId, comp) in netComps.Value)
+                foreach (var (netId, comp) in meta.NetComponents)
                 {
                     if (!comp.NetSyncEnabled)
                         continue;
@@ -549,13 +545,13 @@ namespace Robust.Client.GameStates
                 {
                     foreach (var netId in netIds)
                     {
-                        if (_entities.HasComponent(entity, netId))
+                        if (meta.NetComponents.ContainsKey(netId))
                             continue;
 
                         if (!last.TryGetValue(netId, out var state))
                             continue;
 
-                        var comp = _entityManager.AddComponent(entity, netId);
+                        var comp = _entityManager.AddComponent(entity, netId, meta);
 
                         if (_sawmill.Level <= LogLevel.Debug)
                             _sawmill.Debug($"  A component was removed: {comp.GetType()}");
@@ -597,11 +593,11 @@ namespace Robust.Client.GameStates
 
             foreach (var netEntity in createdEntities)
             {
-                var createdEntity = _entityManager.GetEntity(netEntity);
+                var (createdEntity, meta) = _entityManager.GetEntityData(netEntity);
                 var compData = new Dictionary<ushort, ComponentState>();
                 outputData.Add(netEntity, compData);
 
-                foreach (var (netId, component) in _entityManager.GetNetComponents(createdEntity))
+                foreach (var (netId, component) in meta.NetComponents)
                 {
                     if (!component.NetSyncEnabled)
                         continue;
@@ -692,9 +688,9 @@ namespace Robust.Client.GameStates
 
                     var uid = _entities.CreateEntity(metaState.PrototypeId);
                     _toCreate.Add(es.NetEntity, es);
-                    _toApply.Add(uid, (es.NetEntity, false, GameTick.Zero, es, null));
-
                     var newMeta = metas.GetComponent(uid);
+                    _toApply.Add(uid, (es.NetEntity, newMeta, false, GameTick.Zero, es, null));
+
 
                     // Client creates a client-side net entity for the newly created entity.
                     // We need to clear this mapping before assigning the real net id.
@@ -742,7 +738,7 @@ namespace Robust.Client.GameStates
                     continue;
                 }
 
-                _toApply.Add(uid, (es.NetEntity, isEnteringPvs, meta.LastStateApplied, es, null));
+                _toApply.Add(uid, (es.NetEntity, meta, isEnteringPvs, meta.LastStateApplied, es, null));
                 meta.LastStateApplied = curState.ToSequence;
             }
 
@@ -756,29 +752,32 @@ namespace Robust.Client.GameStates
             {
                 foreach (var es in nextState.EntityStates.Span)
                 {
-                    if (!_entityManager.TryGetEntity(es.NetEntity, out var uid))
+                    if (!_entityManager.TryGetEntityData(es.NetEntity, out var uid, out var meta))
                         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.Value, out var state))
-                        _toApply[uid.Value] = (es.NetEntity, state.EnteringPvs, state.LastApplied, state.curState, es);
+                        _toApply[uid.Value] = (es.NetEntity, meta, state.EnteringPvs, state.LastApplied, state.curState, es);
                     else
-                        _toApply[uid.Value] = (es.NetEntity, false, GameTick.Zero, null, es);
+                        _toApply[uid.Value] = (es.NetEntity, meta, 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)
             {
+                // State already being re-applied so don't bulldoze it.
                 if (_toApply.ContainsKey(uid))
                     continue;
 
-                _toApply[uid] = (_entityManager.GetNetEntity(uid), false, GameTick.Zero, null, null);
+                // Original entity referencing the NetEntity may have been deleted.
+                if (!metas.TryGetComponent(uid, out var meta))
+                    continue;
+
+                _toApply[uid] = (meta.NetEntity, meta, false, GameTick.Zero, null, null);
             }
 
             var queuedBroadphaseUpdates = new List<(EntityUid, TransformComponent)>(enteringPvs);
@@ -788,7 +787,7 @@ namespace Robust.Client.GameStates
             {
                 foreach (var (entity, data) in _toApply)
                 {
-                    HandleEntityState(entity, data.NetEntity, _entities.EventBus, data.curState,
+                    HandleEntityState(entity, data.NetEntity, data.Meta, _entities.EventBus, data.curState,
                         data.nextState, data.LastApplied, curState.ToSequence, data.EnteringPvs);
 
                     if (!data.EnteringPvs)
@@ -1128,7 +1127,7 @@ namespace Robust.Client.GameStates
 #endif
         }
 
-        private void HandleEntityState(EntityUid uid, NetEntity netEntity, IEventBus bus, EntityState? curState,
+        private void HandleEntityState(EntityUid uid, NetEntity netEntity, MetaDataComponent meta, IEventBus bus, EntityState? curState,
             EntityState? nextState, GameTick lastApplied, GameTick toTick, bool enteringPvs)
         {
             _compStateWork.Clear();
@@ -1137,7 +1136,7 @@ namespace Robust.Client.GameStates
             if (curState?.NetComponents != null)
             {
                 RemQueue<Component> toRemove = new();
-                foreach (var (id, comp) in _entities.GetNetComponents(uid))
+                foreach (var (id, comp) in meta.NetComponents)
                 {
                     if (comp.NetSyncEnabled && !curState.NetComponents.Contains(id))
                         toRemove.Add(comp);
@@ -1145,7 +1144,7 @@ namespace Robust.Client.GameStates
 
                 foreach (var comp in toRemove)
                 {
-                    _entities.RemoveComponent(uid, comp);
+                    _entities.RemoveComponent(uid, comp, meta);
                 }
             }
 
@@ -1158,12 +1157,11 @@ namespace Robust.Client.GameStates
                 // the entity. most notably, all entities will have been ejected from their containers.
                 foreach (var (id, state) in _processor.GetLastServerStates(netEntity))
                 {
-                    if (!_entityManager.TryGetComponent(uid, id, out var comp))
+                    if (!meta.NetComponents.TryGetValue(id, out var comp))
                     {
-                        comp = _compFactory.GetComponent(id);
-                        var newComp = (Component)comp;
-                        newComp.Owner = uid;
-                        _entityManager.AddComponent(uid, newComp, true);
+                        comp = (Component) _compFactory.GetComponent(id);
+                        comp.Owner = uid;
+                        _entityManager.AddComponent(uid, comp, true, metadata: meta);
                     }
 
                     _compStateWork[id] = (comp, state, null);
@@ -1173,12 +1171,11 @@ namespace Robust.Client.GameStates
             {
                 foreach (var compChange in curState.ComponentChanges.Span)
                 {
-                    if (!_entityManager.TryGetComponent(uid, compChange.NetID, out var comp))
+                    if (!meta.NetComponents.TryGetValue(compChange.NetID, out var comp))
                     {
-                        comp = _compFactory.GetComponent(compChange.NetID);
-                        var newComp = (Component)comp;
-                        newComp.Owner = uid;
-                        _entityManager.AddComponent(uid, newComp, true);
+                        comp = (Component) _compFactory.GetComponent(compChange.NetID);
+                        comp.Owner = uid;
+                        _entityManager.AddComponent(uid, comp, true, metadata:meta);
                     }
                     else if (compChange.LastModifiedTick <= lastApplied && lastApplied != GameTick.Zero)
                         continue;
@@ -1194,7 +1191,7 @@ namespace Robust.Client.GameStates
                     if (compState.LastModifiedTick != toTick + 1)
                         continue;
 
-                    if (!_entityManager.TryGetComponent(uid, compState.NetID, out var comp))
+                    if (!meta.NetComponents.TryGetValue(compState.NetID, out var comp))
                     {
                         // The component can be null here due to interp, because the NEXT state will have a new
                         // component, but the component does not yet exist.
@@ -1222,7 +1219,7 @@ namespace Robust.Client.GameStates
                         continue;
 
                     if (_compStateWork.ContainsKey(netId.Value) ||
-                        !_entityManager.TryGetComponent(uid, type, out var comp) ||
+                        !meta.NetComponents.TryGetValue(netId.Value, out var comp) ||
                         !lastState.TryGetValue(netId.Value, out var lastCompState))
                     {
                         continue;
@@ -1242,10 +1239,10 @@ namespace Robust.Client.GameStates
                 catch (Exception e)
                 {
 #if EXCEPTION_TOLERANCE
-                        _sawmill.Error($"Failed to apply comp state: entity={comp.Owner}, comp={comp.GetType()}");
-                        _runtimeLog.LogException(e, $"{nameof(ClientGameStateManager)}.{nameof(HandleEntityState)}");
+                    _sawmill.Error($"Failed to apply comp state: entity={_entities.ToPrettyString(uid)}, comp={comp.GetType()}");
+                    _runtimeLog.LogException(e, $"{nameof(ClientGameStateManager)}.{nameof(HandleEntityState)}");
 #else
-                    _sawmill.Error($"Failed to apply comp state: entity={uid}, comp={comp.GetType()}");
+                    _sawmill.Error($"Failed to apply comp state: entity={_entities.ToPrettyString(uid)}, comp={comp.GetType()}");
                     throw;
 #endif
                 }
@@ -1393,12 +1390,11 @@ namespace Robust.Client.GameStates
 
             foreach (var (id, state) in lastState)
             {
-                if (!_entityManager.TryGetComponent(uid, id, out var comp))
+                if (!meta.NetComponents.TryGetValue(id, out var comp))
                 {
-                    comp = _compFactory.GetComponent(id);
-                    var newComp = (Component)comp;
-                    newComp.Owner = uid;
-                    _entityManager.AddComponent(uid, newComp, true);
+                    comp = (Component) _compFactory.GetComponent(id);
+                    comp.Owner = uid;
+                    _entityManager.AddComponent(uid, comp, true, meta);
                 }
 
                 var handleState = new ComponentHandleState(state, null);
@@ -1407,7 +1403,7 @@ namespace Robust.Client.GameStates
 
             // ensure we don't have any extra components
             RemQueue<Component> toRemove = new();
-            foreach (var (id, comp) in _entities.GetNetComponents(uid))
+            foreach (var (id, comp) in meta.NetComponents)
             {
                 if (comp.NetSyncEnabled && !lastState.ContainsKey(id))
                     toRemove.Add(comp);

Robust.Client/Graphics/IClydeWindow.cs

@@ -38,8 +38,7 @@ namespace Robust.Client.Graphics
         event Action<WindowDestroyedEventArgs> Destroyed;
 
         /// <summary>
-        /// Raised when the window has been definitively closed.
-        /// This means the window must not be used anymore (it is disposed).
+        /// Raised when the window has been resized.
         /// </summary>
         event Action<WindowResizedEventArgs> Resized;
     }

Robust.Client/UserInterface/Controllers/Implementations/EntitySpawningUIController.cs

@@ -10,6 +10,7 @@ using Robust.Client.UserInterface.CustomControls;
 using Robust.Shared.Enums;
 using Robust.Shared.IoC;
 using Robust.Shared.Prototypes;
+using Robust.Shared.Serialization.Manager.Attributes;
 using Robust.Shared.Utility;
 using static Robust.Client.UserInterface.Controls.BaseButton;
 using static Robust.Client.UserInterface.Controls.LineEdit;
@@ -199,7 +200,7 @@ public sealed class EntitySpawningUIController : UIController
                 continue;
             }
 
-            if (prototype.NoSpawn)
+            if (prototype.HideSpawnMenu)
             {
                 continue;
             }

Robust.Client/UserInterface/Tooltips.cs

@@ -44,7 +44,7 @@ namespace Robust.Client.UserInterface
             LayoutContainer.SetPosition(tooltip, new Vector2(screenPosition.X, screenPosition.Y - combinedMinSize.Y));
 
             var right = tooltip.Position.X + combinedMinSize.X;
-            var top = tooltip.Position.Y - combinedMinSize.Y;
+            var top = tooltip.Position.Y;
 
             if (right > screenBounds.X)
             {

Robust.Client/ViewVariables/ClientViewVariablesManager.cs

@@ -190,6 +190,11 @@ namespace Robust.Client.ViewVariables
                 return new VVPropEditorEntityUid();
             }
 
+            if (type == typeof(NetEntity))
+            {
+                return new VVPropEditorNetEntity();
+            }
+
             if (type == typeof(Color))
             {
                 return new VVPropEditorColor();

Robust.Client/ViewVariables/Editors/VVPropEditorEntityUid.cs

@@ -4,7 +4,6 @@ using Robust.Client.UserInterface.Controls;
 using Robust.Shared.Console;
 using Robust.Shared.GameObjects;
 using Robust.Shared.IoC;
-using Robust.Shared.Maths;
 using static Robust.Client.UserInterface.Controls.BoxContainer;
 
 namespace Robust.Client.ViewVariables.Editors
@@ -39,7 +38,8 @@ namespace Robust.Client.ViewVariables.Editors
 
             vvButton.OnPressed += e =>
             {
-                IoCManager.Resolve<IConsoleHost>().ExecuteCommand($"vv {uid}");
+                var id = IoCManager.Resolve<IEntityManager>().GetNetEntity(uid);
+                IoCManager.Resolve<IConsoleHost>().ExecuteCommand($"vv {id}");
             };
 
             hBox.AddChild(lineEdit);

Robust.Client/ViewVariables/Editors/VVPropEditorNetEntity.cs

@@ -0,0 +1,48 @@
+using System.Numerics;
+using Robust.Client.UserInterface;
+using Robust.Client.UserInterface.Controls;
+using Robust.Shared.Console;
+using Robust.Shared.GameObjects;
+using Robust.Shared.IoC;
+using static Robust.Client.UserInterface.Controls.BoxContainer;
+
+namespace Robust.Client.ViewVariables.Editors;
+
+public sealed class VVPropEditorNetEntity : VVPropEditor
+{
+    protected override Control MakeUI(object? value)
+    {
+        var hBox = new BoxContainer
+        {
+            Orientation = LayoutOrientation.Horizontal,
+            MinSize = new Vector2(200, 0)
+        };
+
+        var nuid = (NetEntity)value!;
+        var lineEdit = new LineEdit
+        {
+            Text = nuid.ToString(),
+            Editable = !ReadOnly,
+            HorizontalExpand = true,
+        };
+        if (!ReadOnly)
+        {
+            lineEdit.OnTextEntered += e =>
+                ValueChanged(NetEntity.Parse(e.Text));
+        }
+
+        var vvButton = new Button()
+        {
+            Text = "View",
+        };
+
+        vvButton.OnPressed += e =>
+        {
+            IoCManager.Resolve<IConsoleHost>().ExecuteCommand($"vv {nuid}");
+        };
+
+        hBox.AddChild(lineEdit);
+        hBox.AddChild(vvButton);
+        return hBox;
+    }
+}

Robust.Client/ViewVariables/Instances/ViewVariablesInstanceEntity.cs

@@ -469,8 +469,7 @@ namespace Robust.Client.ViewVariables.Instances
             _entitySession = session;
 
             _membersBlob = await ViewVariablesManager.RequestData<ViewVariablesBlobMembers>(session, new ViewVariablesRequestMembers());
-
-            var uid = (EntityUid) _membersBlob.MemberGroups.SelectMany(p => p.Item2).Single(p => p.Name == "Uid").Value;
+            var uid = (NetEntity) _membersBlob.MemberGroups.SelectMany(p => p.Item2).First(p => p.Value is NetEntity).Value;
 
             Initialize(window, uid);
         }

Robust.Server/GameObjects/EntitySystems/MapLoaderSystem.cs

@@ -879,7 +879,7 @@ public sealed class MapLoaderSystem : EntitySystem
             return;
         }
 
-        foreach (var (netId, component) in EntityManager.GetNetComponents(entity))
+        foreach (var component in metadata.NetComponents.Values)
         {
             var compName = _factory.GetComponentName(component.GetType());
 

Robust.Server/GameObjects/EntitySystems/ServerMetaDataSystem.cs

@@ -7,6 +7,7 @@ namespace Robust.Server.GameObjects;
 public sealed class ServerMetaDataSystem : MetaDataSystem
 {
     [Dependency] private readonly PvsSystem _pvsSystem = default!;
+    private EntityQuery<MetaDataComponent> _mQuery;
 
     public override void Initialize()
     {
@@ -16,6 +17,7 @@ public sealed class ServerMetaDataSystem : MetaDataSystem
 
         EntityManager.ComponentAdded += OnComponentAdded;
         EntityManager.ComponentRemoved += OnComponentRemoved;
+        _mQuery = GetEntityQuery<MetaDataComponent>();
     }
 
     public override void Shutdown()
@@ -45,7 +47,7 @@ public sealed class ServerMetaDataSystem : MetaDataSystem
         if (obj.Terminating || !removed.NetSyncEnabled || (!removed.SessionSpecific && !removed.SendOnlyToOwner))
             return;
 
-        foreach (var (_, comp) in EntityManager.GetNetComponents(obj.BaseArgs.Owner))
+        foreach (var comp in obj.Meta.NetComponents.Values)
         {
             if (comp.LifeStage >= ComponentLifeStage.Removing)
                 continue;
@@ -55,7 +57,7 @@ public sealed class ServerMetaDataSystem : MetaDataSystem
         }
 
         // remove the flag
-        MetaData(obj.BaseArgs.Owner).Flags &= ~MetaDataFlags.SessionSpecific;
+        obj.Meta.Flags &= ~MetaDataFlags.SessionSpecific;
     }
 
     /// <summary>
@@ -67,7 +69,7 @@ public sealed class ServerMetaDataSystem : MetaDataSystem
         if ((meta.Flags & MetaDataFlags.SessionSpecific) == 0)
             return;
 
-        foreach (var (_, comp) in EntityManager.GetNetComponents(uid))
+        foreach (var (_, comp) in meta.NetComponents)
         {
             if (comp.SessionSpecific || comp.SendOnlyToOwner)
                 Dirty(uid, comp);

Robust.Server/GameObjects/ServerEntityManager.cs

@@ -1,5 +1,6 @@
 using System;
 using System.Collections.Generic;
+using System.Diagnostics.CodeAnalysis;
 using JetBrains.Annotations;
 using Prometheus;
 using Robust.Server.Player;
@@ -108,11 +109,15 @@ namespace Robust.Server.GameObjects
             }
         }
 
-        public override EntityStringRepresentation ToPrettyString(EntityUid uid)
+        [return: NotNullIfNotNull("uid")]
+        public override EntityStringRepresentation? ToPrettyString(EntityUid? uid)
         {
+            if (uid == null)
+                return null;
+
             TryGetComponent(uid, out ActorComponent? actor);
 
-            return base.ToPrettyString(uid) with { Session = actor?.PlayerSession };
+            return base.ToPrettyString(uid).Value with { Session = actor?.PlayerSession };
         }
 
         #region IEntityNetworkManager impl
@@ -134,9 +139,6 @@ namespace Robust.Server.GameObjects
         {
             _networkManager.RegisterNetMessage<MsgEntity>(HandleEntityNetworkMessage);
 
-            // For syncing component deletions.
-            ComponentRemoved += OnComponentRemoved;
-
             _playerManager.PlayerStatusChanged += OnPlayerStatusChanged;
 
             _configurationManager.OnValueChanged(CVars.NetLogLateMsg, b => _logLateMsgs = b, true);
@@ -163,15 +165,6 @@ namespace Robust.Server.GameObjects
             return _lastProcessedSequencesCmd[session];
         }
 
-        private void OnComponentRemoved(RemovedComponentEventArgs e)
-        {
-            if (e.Terminating || !e.BaseArgs.Component.NetSyncEnabled)
-                return;
-
-            if (TryGetComponent(e.BaseArgs.Owner, out MetaDataComponent? meta))
-                meta.LastComponentRemoved = _gameTiming.CurTick;
-        }
-
         /// <inheritdoc />
         public void SendSystemNetworkMessage(EntityEventArgs message, bool recordReplay = true)
         {

Robust.Server/GameStates/PvsSystem.cs

@@ -2,6 +2,7 @@ using System;
 using System.Collections.Generic;
 using System.Linq;
 using System.Numerics;
+using System.Runtime.InteropServices;
 using System.Text;
 using Microsoft.Extensions.ObjectPool;
 using Robust.Server.Configuration;
@@ -24,7 +25,7 @@ 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 INetworkedMapManager _mapManager = default!;
     [Shared.IoC.Dependency] private readonly IPlayerManager _playerManager = default!;
     [Shared.IoC.Dependency] private readonly IParallelManager _parallelManager = default!;
     [Shared.IoC.Dependency] private readonly IServerGameStateManager _serverGameStateManager = default!;
@@ -34,10 +35,16 @@ internal sealed partial class PvsSystem : EntitySystem
     public const float ChunkSize = 8;
 
     // TODO make this a cvar. Make it in terms of seconds and tie it to tick rate?
+    // Main issue is that I CBF figuring out the logic for handling it changing mid-game.
     public const int DirtyBufferSize = 20;
     // Note: If a client has ping higher than TickBuffer / TickRate, then the server will treat every entity as if it
     // had entered PVS for the first time. Note that due to the PVS budget, this buffer is easily overwhelmed.
 
+    /// <summary>
+    /// See <see cref="CVars.NetForceAckThreshold"/>.
+    /// </summary>
+    public int ForceAckThreshold { get; private set; }
+
     /// <summary>
     /// Maximum number of pooled objects
     /// </summary>
@@ -70,6 +77,9 @@ internal sealed partial class PvsSystem : EntitySystem
         = new DefaultObjectPool<Dictionary<NetEntity, PvsEntityVisibility>>(
             new DictPolicy<NetEntity, PvsEntityVisibility>(), MaxVisPoolSize);
 
+    private readonly ObjectPool<HashSet<EntityUid>> _uidSetPool
+        = new DefaultObjectPool<HashSet<EntityUid>>(new SetPolicy<EntityUid>(), MaxVisPoolSize);
+
     private readonly ObjectPool<Stack<NetEntity>> _stackPool
         = new DefaultObjectPool<Stack<NetEntity>>(
             new StackPolicy<NetEntity>(), MaxVisPoolSize);
@@ -135,6 +145,7 @@ internal sealed partial class PvsSystem : EntitySystem
 
         _configManager.OnValueChanged(CVars.NetPVS, SetPvs, true);
         _configManager.OnValueChanged(CVars.NetMaxUpdateRange, OnViewsizeChanged, true);
+        _configManager.OnValueChanged(CVars.NetForceAckThreshold, OnForceAckChanged, true);
 
         _serverGameStateManager.ClientAck += OnClientAck;
         _serverGameStateManager.ClientRequestFull += OnClientRequestFull;
@@ -152,6 +163,7 @@ internal sealed partial class PvsSystem : EntitySystem
 
         _configManager.UnsubValueChanged(CVars.NetPVS, SetPvs);
         _configManager.UnsubValueChanged(CVars.NetMaxUpdateRange, OnViewsizeChanged);
+        _configManager.UnsubValueChanged(CVars.NetForceAckThreshold, OnForceAckChanged);
 
         _serverGameStateManager.ClientAck -= OnClientAck;
         _serverGameStateManager.ClientRequestFull -= OnClientRequestFull;
@@ -207,6 +219,11 @@ internal sealed partial class PvsSystem : EntitySystem
         _viewSize = obj * 2;
     }
 
+    private void OnForceAckChanged(int value)
+    {
+        ForceAckThreshold = value;
+    }
+
     private void SetPvs(bool value)
     {
         _seenAllEnts.Clear();
@@ -224,6 +241,7 @@ internal sealed partial class PvsSystem : EntitySystem
     public void CullDeletionHistory(GameTick oldestAck)
     {
         _entityPvsCollection.CullDeletionHistoryUntil(oldestAck);
+        _mapManager.CullDeletionHistory(oldestAck);
     }
 
     #region PVSCollection methods to maybe make public someday:tm:
@@ -310,7 +328,7 @@ internal sealed partial class PvsSystem : EntitySystem
         // since elements are cached grid-/map-relative, we don't need to update a given grids/maps children
         DebugTools.Assert(!_mapManager.IsGrid(uid) && !_mapManager.IsMap(uid));
 
-        var indices = PVSCollection<EntityUid>.GetChunkIndices(coordinates.Position);
+        var indices = PVSCollection<NetEntity>.GetChunkIndices(coordinates.Position);
         if (xform.GridUid != null)
             _entityPvsCollection.UpdateIndex(metadata.NetEntity, xform.GridUid.Value, indices, forceDirty: forceDirty);
         else
@@ -610,8 +628,8 @@ internal sealed partial class PvsSystem : EntitySystem
         var tree = _treePool.Get();
         foreach (var netEntity in chunk)
         {
-            var uid = GetEntity(netEntity);
-            AddToChunkSetRecursively(in uid, in netEntity, visMask, tree, chunkSet);
+            var (uid, meta) = GetEntityData(netEntity);
+            AddToChunkSetRecursively(in uid, in netEntity, meta, visMask, tree, chunkSet);
 #if DEBUG
             var xform = _xformQuery.GetComponent(uid);
             if (chunkLocation is MapChunkLocation)
@@ -645,13 +663,12 @@ internal sealed partial class PvsSystem : EntitySystem
         }
     }
 
-    private bool AddToChunkSetRecursively(in EntityUid uid, in NetEntity netEntity, int visMask, RobustTree<NetEntity> tree, Dictionary<NetEntity, MetaDataComponent> set)
+    private bool AddToChunkSetRecursively(in EntityUid uid, in NetEntity netEntity, MetaDataComponent mComp,
+        int visMask, RobustTree<NetEntity> tree, Dictionary<NetEntity, MetaDataComponent> set)
     {
         if (set.ContainsKey(netEntity))
             return true;
 
-        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)
@@ -672,13 +689,10 @@ internal sealed partial class PvsSystem : EntitySystem
         DebugTools.Assert(!_mapManager.IsGrid(uid) && !_mapManager.IsMap(uid));
 
         var parent = xform.ParentUid;
-        var parentNetEntity = _metaQuery.GetComponent(parent).NetEntity;
+        var parentMeta = _metaQuery.GetComponent(parent);
+        var parentNetEntity = parentMeta.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?
+        if (!AddToChunkSetRecursively(in parent, in parentNetEntity, parentMeta, visMask, tree, set)) //did we just fail to add the parent?
         {
             return false; //we failed? suppose we dont get added either
         }
@@ -733,7 +747,7 @@ internal sealed partial class PvsSystem : EntitySystem
 
             foreach (var rootNode in cache.Value.tree.RootNodes)
             {
-                RecursivelyAddTreeNode(in rootNode, cache.Value.tree, lastAcked, lastSent, visibleEnts, lastSeen, stack, in fromTick,
+                RecursivelyAddTreeNode(in rootNode, cache.Value.tree, lastAcked, lastSent, visibleEnts, lastSeen, cache.Value.metadata, stack, in fromTick,
                         ref newEntityCount, ref enteredEntityCount, ref entStateCount,  in newEntityBudget, in enteredEntityBudget);
             }
         }
@@ -749,7 +763,6 @@ internal sealed partial class PvsSystem : EntitySystem
         }
         globalEnumerator.Dispose();
 
-
         var globalRecursiveEnumerator = _entityPvsCollection.GlobalRecursiveOverridesEnumerator;
         while (globalRecursiveEnumerator.MoveNext())
         {
@@ -794,9 +807,10 @@ internal sealed partial class PvsSystem : EntitySystem
 
         foreach (var (netEntity, visiblity) in visibleEnts)
         {
-            var uid = GetEntity(netEntity);
-
+            EntityUid uid;
+            MetaDataComponent meta;
 #if DEBUG
+            uid = GetEntity(netEntity);
             // if an entity is visible, its parents should always be visible.
             DebugTools.Assert((_xformQuery.GetComponent(uid).ParentUid is not { Valid: true } parent) ||
                               visibleEnts.ContainsKey(_metaQuery.GetComponent(parent).NetEntity),
@@ -805,16 +819,18 @@ internal sealed partial class PvsSystem : EntitySystem
 
             if (sessionData.RequestedFull)
             {
-                entityStates.Add(GetFullEntityState(session, uid, _metaQuery.GetComponent(uid)));
+                (uid, meta) = GetEntityData(netEntity);
+                entityStates.Add(GetFullEntityState(session, uid, meta));
                 continue;
             }
 
             if (visiblity == PvsEntityVisibility.StayedUnchanged)
                 continue;
 
+            (uid, meta) = GetEntityData(netEntity);
             var entered = visiblity == PvsEntityVisibility.Entered;
             var entFromTick = entered ? lastSeen.GetValueOrDefault(netEntity) : fromTick;
-            var state = GetEntityState(session, uid, entFromTick, _metaQuery.GetComponent(uid));
+            var state = GetEntityState(session, uid, entFromTick, meta);
 
             if (entered || !state.Empty)
                 entityStates.Add(state);
@@ -881,6 +897,7 @@ internal sealed partial class PvsSystem : EntitySystem
         Dictionary<NetEntity, PvsEntityVisibility>? lastSent,
         Dictionary<NetEntity, PvsEntityVisibility> toSend,
         Dictionary<NetEntity, GameTick> lastSeen,
+        Dictionary<NetEntity, MetaDataComponent> metaDataCache,
         Stack<NetEntity> stack,
         in GameTick fromTick,
         ref int newEntityCount,
@@ -898,16 +915,22 @@ internal sealed partial class PvsSystem : EntitySystem
             // As every map is parented to uid 0 in the tree we still need to get their children, plus because we go top-down
             // we may find duplicate parents with children we haven't encountered before
             // on different chunks (this is especially common with direct grid children)
-            if (!toSend.ContainsKey(currentNodeIndex))
+
+            ref var value = ref CollectionsMarshal.GetValueRefOrAddDefault(toSend, currentNodeIndex, out var exists);
+            if (!exists)
             {
                 var (entered, shouldAdd) = ProcessEntry(in currentNodeIndex, lastAcked, lastSent, lastSeen,
                     ref newEntityCount, ref enteredEntityCount, newEntityBudget, enteredEntityBudget);
 
                 if (!shouldAdd)
+                {
+                    // In the majority of instances entities do get added.
+                    // So its better to add and maybe remove, rather than checking ContainsKey() and then maybe adding it.
+                    toSend.Remove(currentNodeIndex);
                     continue;
+                }
 
-                var entity = GetEntity(currentNodeIndex);
-                AddToSendSet(in currentNodeIndex, _metaQuery.GetComponent(entity), toSend, fromTick, in entered, ref entStateCount);
+                AddToSendSet(in currentNodeIndex, metaDataCache[currentNodeIndex], ref value, toSend, fromTick, in entered, ref entStateCount);
             }
 
             var node = tree[currentNodeIndex];
@@ -949,21 +972,22 @@ internal sealed partial class PvsSystem : EntitySystem
         }
 
         var metadata = _metaQuery.GetComponent(uid);
-        var netEntity = GetNetEntity(uid, metadata);
+        var netEntity = metadata.NetEntity;
 
         //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(netEntity))
+        ref var value = ref CollectionsMarshal.GetValueRefOrAddDefault(toSend, netEntity, out var exists);
+        if (!exists)
         {
             // 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 netEntity, lastAcked, lastSent, lastSeen, ref newEntityCount, ref enteredEntityCount, newEntityBudget, enteredEntityBudget);
-            AddToSendSet(in netEntity, _metaQuery.GetComponent(uid), toSend, fromTick, in entered, ref entStateCount);
+            AddToSendSet(in netEntity, metadata, ref value, toSend, fromTick, in entered, ref entStateCount);
         }
 
         if (addChildren)
@@ -993,14 +1017,15 @@ internal sealed partial class PvsSystem : EntitySystem
                 continue;
 
             var metadata = _metaQuery.GetComponent(child);
-            var childNetEntity = GetNetEntity(child, metadata);
+            var childNetEntity = metadata.NetEntity;
 
-            if (!toSend.ContainsKey(childNetEntity))
+            ref var value = ref CollectionsMarshal.GetValueRefOrAddDefault(toSend, childNetEntity, out var exists);
+            if (!exists)
             {
                 var (entered, _) = ProcessEntry(in childNetEntity, lastAcked, lastSent, lastSeen, ref newEntityCount,
                     ref enteredEntityCount, newEntityBudget, enteredEntityBudget);
 
-                AddToSendSet(in childNetEntity, metadata, toSend, fromTick, in entered, ref entStateCount);
+                AddToSendSet(in childNetEntity, metadata, ref value, toSend, fromTick, in entered, ref entStateCount);
             }
 
             RecursivelyAddChildren(childXform, lastAcked, lastSent, toSend, lastSeen, fromTick, ref newEntityCount,
@@ -1043,10 +1068,13 @@ internal sealed partial class PvsSystem : EntitySystem
         return (entered, true);
     }
 
-    private void AddToSendSet(in NetEntity netEntity, MetaDataComponent metaDataComponent, Dictionary<NetEntity, PvsEntityVisibility> toSend, GameTick fromTick, in bool entered, ref int entStateCount)
+    private void AddToSendSet(in NetEntity netEntity, MetaDataComponent metaDataComponent,
+        ref PvsEntityVisibility vis, Dictionary<NetEntity, PvsEntityVisibility> toSend,
+        GameTick fromTick, in bool entered, ref int entStateCount)
     {
         if (metaDataComponent.EntityLifeStage >= EntityLifeStage.Terminating)
         {
+            toSend.Remove(netEntity);
             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;
@@ -1054,7 +1082,7 @@ internal sealed partial class PvsSystem : EntitySystem
 
         if (entered)
         {
-            toSend.Add(netEntity, PvsEntityVisibility.Entered);
+            vis = PvsEntityVisibility.Entered;
             entStateCount++;
             return;
         }
@@ -1062,12 +1090,12 @@ internal sealed partial class PvsSystem : EntitySystem
         if (metaDataComponent.EntityLastModifiedTick <= fromTick)
         {
             //entity has been sent before and hasnt been updated since
-            toSend.Add(netEntity, PvsEntityVisibility.StayedUnchanged);
+            vis = PvsEntityVisibility.StayedUnchanged;
             return;
         }
 
         //add us
-        toSend.Add(netEntity, PvsEntityVisibility.StayedChanged);
+        vis = PvsEntityVisibility.StayedChanged;
         entStateCount++;
     }
 
@@ -1077,7 +1105,7 @@ internal sealed partial class PvsSystem : EntitySystem
     public (List<EntityState>?, List<NetEntity>?, GameTick fromTick) GetAllEntityStates(ICommonSession? player, GameTick fromTick, GameTick toTick)
     {
         List<EntityState>? stateEntities;
-        var toSend = new HashSet<EntityUid>();
+        var toSend = _uidSetPool.Get();
         DebugTools.Assert(toSend.Count == 0);
         bool enumerateAll = false;
 
@@ -1126,7 +1154,6 @@ Transform last modified: {Transform(uid).LastModifiedTick}");
         else
         {
             stateEntities = new();
-            var metaQuery = EntityManager.GetEntityQuery<MetaDataComponent>();
             for (var i = fromTick.Value + 1; i <= toTick.Value; i++)
             {
                 if (!TryGetDirtyEntities(new GameTick(i), out var add, out var dirty))
@@ -1137,7 +1164,7 @@ Transform last modified: {Transform(uid).LastModifiedTick}");
 
                 foreach (var uid in add)
                 {
-                    if (!toSend.Add(uid) || !metaQuery.TryGetComponent(uid, out var md))
+                    if (!toSend.Add(uid) || !_metaQuery.TryGetComponent(uid, out var md))
                         continue;
 
                     DebugTools.Assert(md.EntityLifeStage >= EntityLifeStage.Initialized);
@@ -1164,7 +1191,7 @@ Transform last modified: {Transform(uid).LastModifiedTick}");
                 foreach (var uid in dirty)
                 {
                     DebugTools.Assert(!add.Contains(uid));
-                    if (!toSend.Add(uid) || !metaQuery.TryGetComponent(uid, out var md))
+                    if (!toSend.Add(uid) || !_metaQuery.TryGetComponent(uid, out var md))
                         continue;
 
                     DebugTools.Assert(md.EntityLifeStage >= EntityLifeStage.Initialized);
@@ -1179,6 +1206,7 @@ Transform last modified: {Transform(uid).LastModifiedTick}");
             }
         }
 
+        _uidSetPool.Return(toSend);
         var deletions = _entityPvsCollection.GetDeletedIndices(fromTick);
 
         if (stateEntities.Count == 0)
@@ -1203,7 +1231,7 @@ Transform last modified: {Transform(uid).LastModifiedTick}");
         bool sendCompList = meta.LastComponentRemoved > fromTick;
         HashSet<ushort>? netComps = sendCompList ? new() : null;
 
-        foreach (var (netId, component) in EntityManager.GetNetComponents(entityUid))
+        foreach (var (netId, component) in meta.NetComponents)
         {
             if (!component.NetSyncEnabled)
                 continue;
@@ -1252,7 +1280,7 @@ Transform last modified: {Transform(uid).LastModifiedTick}");
 
         HashSet<ushort> netComps = new();
 
-        foreach (var (netId, component) in EntityManager.GetNetComponents(entityUid))
+        foreach (var (netId, component) in meta.NetComponents)
         {
             if (!component.NetSyncEnabled)
                 continue;
@@ -1276,34 +1304,28 @@ Transform last modified: {Transform(uid).LastModifiedTick}");
 
     private EntityUid[] GetSessionViewers(ICommonSession session)
     {
-        if (session.Status != SessionStatus.InGame)
+        if (session.Status != SessionStatus.InGame || session is not IPlayerSession sess)
             return Array.Empty<EntityUid>();
 
+        // Fast path
+        if (sess.ViewSubscriptionCount == 0)
+        {
+            if (session.AttachedEntity == null)
+                return Array.Empty<EntityUid>();
+
+            return new[] { session.AttachedEntity.Value };
+        }
+
         var viewers = new HashSet<EntityUid>();
-
         if (session.AttachedEntity != null)
-        {
-            // Fast path
-            if (session is IPlayerSession { ViewSubscriptionCount: 0 })
-            {
-                return new[] { session.AttachedEntity.Value };
-            }
-
             viewers.Add(session.AttachedEntity.Value);
-        }
 
-        // This is awful, but we're not gonna add the list of view subscriptions to common session.
-        if (session is IPlayerSession playerSession)
+        foreach (var uid in sess.ViewSubscriptions)
         {
-            foreach (var uid in playerSession.ViewSubscriptions)
-            {
-                viewers.Add(uid);
-            }
+            viewers.Add(uid);
         }
 
-        var viewerArray = viewers.ToArray();
-
-        return viewerArray;
+        return viewers.ToArray();
     }
 
     // Read Safe

Robust.Server/GameStates/ServerGameStateManager.cs

@@ -24,6 +24,7 @@ using SharpZstd.Interop;
 using Microsoft.Extensions.ObjectPool;
 using Prometheus;
 using Robust.Server.Replays;
+using Robust.Shared.Console;
 using Robust.Shared.Map.Components;
 using Robust.Shared.Players;
 
@@ -48,6 +49,7 @@ namespace Robust.Server.GameStates
         [Dependency] private readonly IServerEntityNetworkManager _entityNetworkManager = default!;
         [Dependency] private readonly IConfigurationManager _cfg = default!;
         [Dependency] private readonly IParallelManager _parallelMgr = default!;
+        [Dependency] private readonly IConsoleHost _conHost = default!;
 
         private static readonly Histogram _usageHistogram = Metrics.CreateHistogram("robust_game_state_update_usage",
             "Amount of time spent processing different parts of the game state update", new HistogramConfiguration
@@ -83,6 +85,25 @@ namespace Robust.Server.GameStates
             _parallelMgr.AddAndInvokeParallelCountChanged(ResetParallelism);
 
             _cfg.OnValueChanged(CVars.NetPVSCompressLevel, _ => ResetParallelism(), true);
+
+            // temporary command for debugging PVS bugs.
+            _conHost.RegisterCommand("print_pvs_ack", PrintPvsAckInfo);
+        }
+
+        private void PrintPvsAckInfo(IConsoleShell shell, string argstr, string[] args)
+        {
+            var ack = _pvs.PlayerData.Min(x => x.Value.LastReceivedAck);
+            var players = _pvs.PlayerData
+                .Where(x => x.Value.LastReceivedAck == ack)
+                .Select(x => x.Key)
+                .Select(x => $"{x.Name} ({_entityManager.ToPrettyString(x.AttachedEntity)})");
+
+            shell.WriteLine($@"Current tick: {_gameTiming.CurTick}
+Stored oldest acked tick: {_lastOldestAck}
+Deletion history size: {_pvs.EntityPVSCollection.GetDeletedIndices(GameTick.First)?.Count ?? 0}
+Actual oldest: {ack}
+Oldest acked clients: {string.Join(", ", players)}
+");
         }
 
         private void ResetParallelism()
@@ -147,15 +168,6 @@ namespace Robust.Server.GameStates
         /// <inheritdoc />
         public void SendGameStateUpdate()
         {
-            if (!_networkManager.IsConnected)
-            {
-                // Prevent deletions piling up if we have no clients.
-                _pvs.CullDeletionHistory(GameTick.MaxValue);
-                _mapManager.CullDeletionHistory(GameTick.MaxValue);
-                _pvs.CleanupDirty(Enumerable.Empty<IPlayerSession>());
-                return;
-            }
-
             var players = _playerManager.ServerSessions.Where(o => o.Status == SessionStatus.InGame).ToArray();
 
             // Update entity positions in PVS chunks/collections
@@ -195,14 +207,21 @@ namespace Robust.Server.GameStates
                 _pvs.CleanupDirty(players);
             }
 
-            // keep the deletion history buffers clean
-            if (oldestAck > _lastOldestAck)
+            if (oldestAck == GameTick.MaxValue)
             {
-                using var _ = _usageHistogram.WithLabels("Cull History").NewTimer();
-                _lastOldestAck = oldestAck;
-                _pvs.CullDeletionHistory(oldestAck);
-                _mapManager.CullDeletionHistory(oldestAck);
+                // There were no connected players?
+                // In that case we just clear all deletion history.
+                _pvs.CullDeletionHistory(GameTick.MaxValue);
+                _lastOldestAck = GameTick.Zero;
+                return;
             }
+
+            if (oldestAck == _lastOldestAck)
+                return;
+
+            _lastOldestAck = oldestAck;
+            using var __ = _usageHistogram.WithLabels("Cull History").NewTimer();
+            _pvs.CullDeletionHistory(oldestAck);
         }
 
         private GameTick SendStates(IPlayerSession[] players, PvsData? pvsData)
@@ -210,8 +229,6 @@ namespace Robust.Server.GameStates
             var inputSystem = _systemManager.GetEntitySystem<InputSystem>();
             var opts = new ParallelOptions {MaxDegreeOfParallelism = _parallelMgr.ParallelProcessCount};
             var oldestAckValue = GameTick.MaxValue.Value;
-            var tQuery = _entityManager.GetEntityQuery<TransformComponent>();
-            var mQuery = _entityManager.GetEntityQuery<MetaDataComponent>();
 
             // Replays process game states in parallel with players
             Parallel.For(-1, players.Length, opts, _threadResourcesPool.Get, SendPlayer, _threadResourcesPool.Return);
@@ -225,7 +242,7 @@ namespace Robust.Server.GameStates
                     PvsEventSource.Log.WorkStart(_gameTiming.CurTick.Value, i, guid);
 
                     if (i >= 0)
-                        SendStateUpdate(i, resource, inputSystem, players[i], pvsData, mQuery, tQuery, ref oldestAckValue);
+                        SendStateUpdate(i, resource, inputSystem, players[i], pvsData, ref oldestAckValue);
                     else
                         _replay.Update();
 
@@ -304,8 +321,6 @@ namespace Robust.Server.GameStates
             InputSystem inputSystem,
             IPlayerSession session,
             PvsData? pvsData,
-            EntityQuery<MetaDataComponent> mQuery,
-            EntityQuery<TransformComponent> tQuery,
             ref uint oldestAckValue)
         {
             var channel = session.ConnectedClient;
@@ -358,6 +373,21 @@ namespace Robust.Server.GameStates
             // If the state is too big we let Lidgren send it reliably. This is to avoid a situation where a state is so
             // large that it (or part of it) consistently gets dropped. When we send reliably, we immediately update the
             // ack so that the next state will not also be huge.
+            //
+            // We also do this if the client's last ack is too old. This helps prevent things like the entity deletion
+            // history from becoming too bloated if a bad client fails to send acks for whatever reason.
+
+            if (_gameTiming.CurTick.Value > lastAck.Value + _pvs.ForceAckThreshold)
+            {
+                stateUpdateMessage.ForceSendReliably = true;
+
+                // Aside from the time shortly after connecting, this shouldn't be common. If it is happening,
+                // something is probably wrong. If it is more frequent than I think, this can be downgraded to a warning.
+                var connectedTime = (DateTime.UtcNow - session.ConnectedTime).TotalMinutes;
+                if (lastAck > GameTick.Zero && connectedTime > 1)
+                    _logger.Error($"Client {session} exceeded ack-tick threshold. Last ack: {lastAck}. Cur tick: {_gameTiming.CurTick}. Connect time: {connectedTime} minutes");
+            }
+
             if (stateUpdateMessage.ShouldSendReliably())
             {
                 sessionData.LastReceivedAck = _gameTiming.CurTick;

Robust.Server/Prototypes/ServerPrototypeManager.cs

@@ -51,6 +51,7 @@ namespace Robust.Server.Prototypes
 
         public override void LoadDefaultPrototypes(Dictionary<Type, HashSet<string>>? changed = null)
         {
+            LoadDirectory(new("/EnginePrototypes/"), changed: changed);
             LoadDirectory(_server.Options.PrototypeDirectory, changed: changed);
             ResolveResults();
         }

Robust.Server/ViewVariables/ViewVariablesTrait.cs

@@ -1,6 +1,7 @@
 using System;
 using System.Collections.Generic;
 using Robust.Server.ViewVariables.Traits;
+using Robust.Shared.GameObjects;
 using Robust.Shared.IoC;
 using Robust.Shared.Network.Messages;
 using Robust.Shared.Prototypes;
@@ -92,6 +93,9 @@ namespace Robust.Server.ViewVariables
                 return null;
             }
 
+            if (value is EntityUid uid)
+                return IoCManager.Resolve<IEntityManager>().GetNetEntity(uid);
+
             var valType = value.GetType();
             if (!valType.IsValueType)
             {

Robust.Shared.Maths/Box2.cs

@@ -2,6 +2,7 @@ using System;
 using System.Numerics;
 using System.Runtime.CompilerServices;
 using System.Runtime.InteropServices;
+using System.Runtime.Intrinsics;
 using JetBrains.Annotations;
 using Robust.Shared.Utility;
 
@@ -35,9 +36,15 @@ namespace Robust.Shared.Maths
         /// </summary>
         [FieldOffset(sizeof(float) * 3)] public float Top;
 
+        [NonSerialized]
         [FieldOffset(sizeof(float) * 0)] public Vector2 BottomLeft;
+
+        [NonSerialized]
         [FieldOffset(sizeof(float) * 2)] public Vector2 TopRight;
 
+        [NonSerialized]
+        [FieldOffset(sizeof(float) * 0)] public System.Numerics.Vector4 AsVector4;
+
         public readonly Vector2 BottomRight
         {
             [MethodImpl(MethodImplOptions.AggressiveInlining)]
@@ -141,6 +148,11 @@ namespace Robust.Shared.Maths
             return new Box2(min, max);
         }
 
+        public readonly bool HasNan()
+        {
+            return Vector128.EqualsAny(AsVector4.AsVector128(), Vector128.Create(float.NaN));
+        }
+
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
         [Pure]
         public readonly bool Intersects(in Box2 other)

Robust.Shared.Scripting/ScriptGlobalsShared.cs

@@ -218,7 +218,8 @@ namespace Robust.Shared.Scripting
         public EntityPrototype? Prototype(EntityUid uid)
             => ent.GetComponent<MetaDataComponent>(uid).EntityPrototype;
 
-        public EntityStringRepresentation ToPrettyString(EntityUid uid)
+        [return: NotNullIfNotNull("uid")]
+        public EntityStringRepresentation? ToPrettyString(EntityUid? uid)
             => ent.ToPrettyString(uid);
 
         public IEnumerable<IComponent> AllComps(EntityUid uid)

Robust.Shared/CVars.cs

@@ -172,6 +172,13 @@ namespace Robust.Shared
         public static readonly CVarDef<float> NetMaxUpdateRange =
             CVarDef.Create("net.maxupdaterange", 12.5f, CVar.ARCHIVE | CVar.REPLICATED | CVar.SERVER);
 
+        /// <summary>
+        /// Maximum allowed delay between the current tick and a client's last acknowledged tick before we send the
+        /// next game state reliably and simply force update the acked tick,
+        /// </summary>
+        public static readonly CVarDef<int> NetForceAckThreshold =
+            CVarDef.Create("net.force_ack_threshold", 40, CVar.ARCHIVE | CVar.SERVERONLY);
+
         /// <summary>
         /// This limits the number of new entities that can be sent to a client in a single game state. This exists to
         /// avoid stuttering on the client when it has to spawn a bunch of entities in a single tick. If ever entity

Robust.Shared/Containers/BaseContainer.cs

@@ -11,7 +11,9 @@ using Robust.Shared.Utility;
 using Robust.Shared.ViewVariables;
 using System;
 using System.Collections.Generic;
+using System.Linq;
 using System.Numerics;
+using Robust.Shared.Log;
 using Robust.Shared.Serialization;
 
 namespace Robust.Shared.Containers
@@ -25,9 +27,13 @@ namespace Robust.Shared.Containers
         /// <summary>
         /// Readonly collection of all the entities contained within this specific container
         /// </summary>
-        [ViewVariables]
         public abstract IReadOnlyList<EntityUid> ContainedEntities { get; }
 
+        // VV convenience field
+        [ViewVariables]
+        private IReadOnlyList<NetEntity> NetContainedEntities => ContainedEntities
+            .Select(o => IoCManager.Resolve<IEntityManager>().GetNetEntity(o)).ToList();
+
         /// <summary>
         /// Number of contained entities.
         /// </summary>
@@ -106,6 +112,7 @@ namespace Robust.Shared.Containers
             DebugTools.Assert(ownerTransform == null || ownerTransform.Owner == Owner);
             DebugTools.Assert(physics == null || physics.Owner == toinsert);
             DebugTools.Assert(!ExpectedEntities.Contains(entMan.GetNetEntity(toinsert)));
+            DebugTools.Assert(Manager.Containers.ContainsKey(ID));
 
             var physicsQuery = entMan.GetEntityQuery<PhysicsComponent>();
             var transformQuery = entMan.GetEntityQuery<TransformComponent>();
@@ -116,6 +123,26 @@ namespace Robust.Shared.Containers
             var jointSys = entMan.EntitySysManager.GetEntitySystem<SharedJointSystem>();
             var containerSys = entMan.EntitySysManager.GetEntitySystem<SharedContainerSystem>();
 
+            // If someone is attempting to insert an entity into a container that is getting deleted, then we will
+            // automatically delete that entity. I.e., the insertion automatically "succeeds" and both entities get deleted.
+            // This is consistent with what happens if you attempt to attach an entity to a terminating parent.
+
+            if (!entMan.TryGetComponent(Owner, out MetaDataComponent? ownerMeta))
+            {
+                Logger.ErrorS("container",
+                    $"Attempted to insert an entity {entMan.ToPrettyString(toinsert)} into a non-existent entity.");
+                entMan.QueueDeleteEntity(toinsert);
+                return false;
+            }
+
+            if (ownerMeta.EntityLifeStage >= EntityLifeStage.Terminating)
+            {
+                Logger.ErrorS("container",
+                    $"Attempted to insert an entity {entMan.ToPrettyString(toinsert)} into an entity that is terminating. Entity: {entMan.ToPrettyString(Owner)}.");
+                entMan.QueueDeleteEntity(toinsert);
+                return false;
+            }
+
             //Verify we can insert into this container
             if (!force && !containerSys.CanInsert(toinsert, this))
                 return false;

Robust.Shared/GameObjects/ComponentEventArgs.cs

@@ -46,10 +46,13 @@ namespace Robust.Shared.GameObjects
 
         public readonly bool Terminating;
 
-        public RemovedComponentEventArgs(ComponentEventArgs baseArgs, bool terminating)
+        public readonly MetaDataComponent Meta;
+
+        public RemovedComponentEventArgs(ComponentEventArgs baseArgs, bool terminating, MetaDataComponent meta)
         {
             BaseArgs = baseArgs;
             Terminating = terminating;
+            Meta = meta;
         }
     }
 

Robust.Shared/GameObjects/ComponentFactory.cs

@@ -59,9 +59,6 @@ namespace Robust.Shared.GameObjects
         /// <inheritdoc />
         public event Action<ComponentRegistration>? ComponentAdded;
 
-        /// <inheritdoc />
-        public event Action<ComponentRegistration, CompIdx>? ComponentReferenceAdded;
-
         /// <inheritdoc />
         public event Action<string>? ComponentIgnoreAdded;
 
@@ -173,31 +170,6 @@ namespace Robust.Shared.GameObjects
             }
         }
 
-        private void RegisterReference(Type target, Type @interface)
-        {
-            if (_networkedComponents is not null)
-                throw new ComponentRegistrationLockException();
-
-            if (!types.ContainsKey(target))
-            {
-                throw new InvalidOperationException($"Unregistered type: {target}");
-            }
-
-            if (@interface == typeof(MetaDataComponent) || @interface == typeof(TransformComponent))
-                throw new InvalidOperationException("Cannot make Transform or Metadata a reference type!");
-
-            var idx = CompIdx.Index(@interface);
-            _idxToType[idx] = @interface;
-
-            var registration = types[target];
-            if (registration.References.Contains(idx))
-            {
-                throw new InvalidOperationException($"Attempted to register a reference twice: {@interface}");
-            }
-            registration.References.Add(idx);
-            ComponentReferenceAdded?.Invoke(registration, idx);
-        }
-
         public void IgnoreMissingComponents(string postfix = "")
         {
             if (_ignoreMissingComponentPostfix != null && _ignoreMissingComponentPostfix != postfix)
@@ -333,7 +305,7 @@ namespace Robust.Shared.GameObjects
         {
             return GetRegistration(netID).Name;
         }
-        
+
         public ComponentRegistration GetRegistration(ushort netID)
         {
             if (_networkedComponents is null)
@@ -450,28 +422,11 @@ namespace Robust.Shared.GameObjects
             }
 
             Register(type);
-
-#pragma warning disable CS0618
-            foreach (var attribute in Attribute.GetCustomAttributes(type, typeof(ComponentReferenceAttribute)))
-            {
-                var cast = (ComponentReferenceAttribute) attribute;
-#pragma warning restore CS0618
-
-                var refType = cast.ReferenceType;
-
-                if (!refType.IsAssignableFrom(type))
-                {
-                    _sawmill.Error("Type {0} has reference for type it does not implement: {1}.", type, refType);
-                    continue;
-                }
-
-                RegisterReference(type, refType);
-            }
         }
 
         public IEnumerable<CompIdx> GetAllRefTypes()
         {
-            return AllRegistrations.SelectMany(r => r.References).Distinct();
+            return AllRegistrations.Select(x => x.Idx).Distinct();
         }
 
         /// <inheritdoc />

Robust.Shared/GameObjects/ComponentReferenceAttribute.cs

@@ -1,30 +0,0 @@
-using System;
-
-namespace Robust.Shared.GameObjects;
-
-/*
- * Obsoleted because this has a massive performance cost and it is not worth it.
- */
-
-/// <summary>
-///     Marks a component as having a specific reference type,
-///     for use with <see cref="RegisterComponentAttribute"/>.
-/// </summary>
-[Obsolete("Refactor your code to not use component references.")]
-[AttributeUsage(AttributeTargets.Class, Inherited = false, AllowMultiple = true)]
-public sealed class ComponentReferenceAttribute : Attribute
-{
-    /// <summary>
-    ///     The type this component is a reference to.
-    /// </summary>
-    public Type ReferenceType { get; }
-
-    /// <summary>
-    ///     Default constructor.
-    /// </summary>
-    /// <param name="referenceType">The type this component is a reference to.</param>
-    public ComponentReferenceAttribute(Type referenceType)
-    {
-        ReferenceType = referenceType;
-    }
-}

Robust.Shared/GameObjects/ComponentRegistration.cs

@@ -33,8 +33,6 @@ public sealed class ComponentRegistration
     /// </summary>
     public Type Type { get; }
 
-    public ValueList<CompIdx> References;
-
     // Internal for sandboxing.
     // Avoid content passing an instance of this to ComponentFactory to get any type they want instantiated.
     internal ComponentRegistration(string name, Type type, CompIdx idx)
@@ -42,7 +40,6 @@ public sealed class ComponentRegistration
         Name = name;
         Type = type;
         Idx = idx;
-        References.Add(idx);
     }
 
     public override string ToString()

Robust.Shared/GameObjects/Components/Eye/EyeComponent.cs

@@ -9,7 +9,7 @@ using Robust.Shared.ViewVariables;
 
 namespace Robust.Shared.GameObjects
 {
-    [RegisterComponent, NetworkedComponent, Access(typeof(SharedEyeSystem)), AutoGenerateComponentState]
+    [RegisterComponent, NetworkedComponent, Access(typeof(SharedEyeSystem)), AutoGenerateComponentState(true)]
     public sealed partial class EyeComponent : Component
     {
         #region Client

Robust.Shared/GameObjects/Components/Light/SharedPointLightComponent.cs

@@ -1,9 +1,11 @@
+using System;
 using Robust.Shared.Animations;
 using Robust.Shared.GameStates;
 using Robust.Shared.Maths;
 using Robust.Shared.Serialization.Manager.Attributes;
 using Robust.Shared.ViewVariables;
 using System.Numerics;
+using Robust.Shared.IoC;
 
 namespace Robust.Shared.GameObjects
 {
@@ -39,16 +41,35 @@ namespace Robust.Shared.GameObjects
 
         [Access(typeof(SharedPointLightSystem))]
         [DataField("enabled")]
+        public bool Enabled = true;
+
+        // TODO ECS animations
         [Animatable]
-        public bool Enabled { get; set; } = true;
+        public bool AnimatedEnable
+        {
+            [Obsolete]
+            get => Enabled;
+
+            [Obsolete]
+            set => IoCManager.Resolve<IEntityManager>().System<SharedPointLightSystem>().SetEnabled(Owner, value, this);
+        }
+
+        // TODO ECS animations
+        [Animatable]
+        public float AnimatedRadius
+        {
+            [Obsolete]
+            get => Radius;
+            [Obsolete]
+            set => IoCManager.Resolve<IEntityManager>().System<SharedPointLightSystem>().SetRadius(Owner, value, this);
+        }
 
         /// <summary>
         /// How far the light projects.
         /// </summary>
         [DataField("radius")]
         [Access(typeof(SharedPointLightSystem))]
-        [Animatable]
-        public float Radius { get; set; } = 5f;
+        public float Radius = 5f;
 
         [ViewVariables]
         public bool ContainerOccluded;

Robust.Shared/GameObjects/Components/MetaDataComponent.cs

@@ -8,6 +8,7 @@ using Robust.Shared.Timing;
 using Robust.Shared.Utility;
 using Robust.Shared.ViewVariables;
 using System;
+using System.Collections.Generic;
 
 namespace Robust.Shared.GameObjects
 {
@@ -63,6 +64,12 @@ namespace Robust.Shared.GameObjects
         [DataField("desc")] internal string? _entityDescription;
         internal EntityPrototype? _entityPrototype;
 
+        /// <summary>
+        /// The components attached to the entity that are currently networked.
+        /// </summary>
+        [ViewVariables]
+        internal readonly Dictionary<ushort, Component> NetComponents = new();
+
         /// <summary>
         /// Network identifier for this entity.
         /// </summary>
@@ -87,7 +94,8 @@ namespace Robust.Shared.GameObjects
         public GameTick LastStateApplied { get; internal set; } = GameTick.Zero;
 
         /// <summary>
-        ///     This is the most recent tick at which some component was removed from this entity.
+        ///     This is the most recent tick at which a networked component was removed from this entity.
+        ///     Currently only reliable server-side, client side prediction may cause the value to be wrong.
         /// </summary>
         [ViewVariables]
         public GameTick LastComponentRemoved { get; internal set; } = GameTick.Zero;

Robust.Shared/GameObjects/Components/Transform/TransformComponent.cs

@@ -25,6 +25,10 @@ namespace Robust.Shared.GameObjects
         [Dependency] private readonly IEntityManager _entMan = default!;
         [Dependency] private readonly IGameTiming _gameTiming = default!;
 
+        // Currently this field just exists for VV. In future, it might become a real field
+        [ViewVariables]
+        private NetEntity NetParent => _entMan.GetNetEntity(_parent);
+
         [DataField("parent")] internal EntityUid _parent;
         [DataField("pos")] internal Vector2 _localPosition = Vector2.Zero; // holds offset from grid, or offset from parent
         [DataField("rot")] internal Angle _localRotation; // local rotation

Robust.Shared/GameObjects/EntityEventBus.Directed.cs

@@ -116,7 +116,6 @@ namespace Robust.Shared.GameObjects
 
             // Dynamic handling of components is only for RobustUnitTest compatibility spaghetti.
             _comFac.ComponentAdded += ComFacOnComponentAdded;
-            _comFac.ComponentReferenceAdded += ComFacOnComponentReferenceAdded;
 
             InitEntSubscriptionsArray();
         }
@@ -310,11 +309,6 @@ namespace Robust.Shared.GameObjects
             EntUnsubscribe(CompIdx.Index<TComp>(), typeof(TEvent));
         }
 
-        private void ComFacOnComponentReferenceAdded(ComponentRegistration arg1, CompIdx arg2)
-        {
-            CompIdx.RefArray(ref _entSubscriptions, arg2) ??= new Dictionary<Type, DirectedRegistration>();
-        }
-
         private void ComFacOnComponentAdded(ComponentRegistration obj)
         {
             CompIdx.RefArray(ref _entSubscriptions, obj.Idx) ??= new Dictionary<Type, DirectedRegistration>();
@@ -427,40 +421,35 @@ namespace Robust.Shared.GameObjects
         private void EntAddComponent(EntityUid euid, CompIdx compType)
         {
             var eventTable = _entEventTables[euid];
+            var compSubs = _entSubscriptions[compType.Value]!;
 
-            var enumerator = EntGetReferences(compType);
-            while (enumerator.MoveNext(out var type))
+            foreach (var evType in compSubs.Keys)
             {
-                var compSubs = _entSubscriptions[type.Value]!;
+                // Skip adding this to significantly reduce memory use and GC noise on entity create.
+                if (_eventData[evType].ComponentEvent)
+                    continue;
 
-                foreach (var (evType, _) in compSubs)
-                {
-                    // Skip adding this to significantly reduce memory use and GC noise on entity create.
-                    if (_eventData[evType].ComponentEvent)
-                        continue;
+                if (eventTable.Free < 0)
+                    GrowEventTable(eventTable);
 
-                    if (eventTable.Free < 0)
-                        GrowEventTable(eventTable);
+                DebugTools.Assert(eventTable.Free >= 0);
 
-                    DebugTools.Assert(eventTable.Free >= 0);
+                ref var eventStartIdx = ref CollectionsMarshal.GetValueRefOrAddDefault(
+                    eventTable.EventIndices,
+                    evType,
+                    out var exists);
 
-                    ref var eventStartIdx = ref CollectionsMarshal.GetValueRefOrAddDefault(
-                        eventTable.EventIndices,
-                        evType,
-                        out var exists);
+                // Allocate linked list entry by popping free list.
+                var entryIdx = eventTable.Free;
+                ref var entry = ref eventTable.ComponentLists[entryIdx];
+                eventTable.Free = entry.Next;
 
-                    // Allocate linked list entry by popping free list.
-                    var entryIdx = eventTable.Free;
-                    ref var entry = ref eventTable.ComponentLists[entryIdx];
-                    eventTable.Free = entry.Next;
+                // Set it up
+                entry.Component = compType;
+                entry.Next = exists ? eventStartIdx : -1;
 
-                    // Set it up
-                    entry.Component = type;
-                    entry.Next = exists ? eventStartIdx : -1;
-
-                    // Assign new list entry to EventIndices dictionary.
-                    eventStartIdx = entryIdx;
-                }
+                // Assign new list entry to EventIndices dictionary.
+                eventStartIdx = entryIdx;
             }
         }
 
@@ -493,51 +482,46 @@ namespace Robust.Shared.GameObjects
         private void EntRemoveComponent(EntityUid euid, CompIdx compType)
         {
             var eventTable = _entEventTables[euid];
+            var compSubs = _entSubscriptions[compType.Value]!;
 
-            var enumerator = EntGetReferences(compType);
-            while (enumerator.MoveNext(out var type))
+            foreach (var evType in compSubs.Keys)
             {
-                var compSubs = _entSubscriptions[type.Value]!;
+                ref var dictIdx = ref CollectionsMarshal.GetValueRefOrNullRef(eventTable.EventIndices, evType);
+                if (Unsafe.IsNullRef(ref dictIdx))
+                    continue;
 
-                foreach (var (evType, _) in compSubs)
+                ref var updateNext = ref dictIdx;
+
+                // Go over linked list to find index of component.
+                var entryIdx = dictIdx;
+                ref var entry = ref Unsafe.NullRef<EventTableListEntry>();
+                while (true)
                 {
-                    ref var dictIdx = ref CollectionsMarshal.GetValueRefOrNullRef(eventTable.EventIndices, evType);
-                    if (Unsafe.IsNullRef(ref dictIdx))
-                        continue;
-
-                    ref var updateNext = ref dictIdx;
-
-                    // Go over linked list to find index of component.
-                    var entryIdx = dictIdx;
-                    ref var entry = ref Unsafe.NullRef<EventTableListEntry>();
-                    while (true)
+                    entry = ref eventTable.ComponentLists[entryIdx];
+                    if (entry.Component == compType)
                     {
-                        entry = ref eventTable.ComponentLists[entryIdx];
-                        if (entry.Component == type)
-                        {
-                            // Found
-                            break;
-                        }
-
-                        entryIdx = entry.Next;
-                        updateNext = ref entry.Next;
+                        // Found
+                        break;
                     }
 
-                    if (entry.Next == -1 && Unsafe.AreSame(ref dictIdx, ref updateNext))
-                    {
-                        // Last entry for this event type, remove from dict.
-                        eventTable.EventIndices.Remove(evType);
-                    }
-                    else
-                    {
-                        // Rewrite previous index to point to next in chain.
-                        updateNext = entry.Next;
-                    }
-
-                    // Push entry back onto free list.
-                    entry.Next = eventTable.Free;
-                    eventTable.Free = entryIdx;
+                    entryIdx = entry.Next;
+                    updateNext = ref entry.Next;
                 }
+
+                if (entry.Next == -1 && Unsafe.AreSame(ref dictIdx, ref updateNext))
+                {
+                    // Last entry for this event type, remove from dict.
+                    eventTable.EventIndices.Remove(evType);
+                }
+                else
+                {
+                    // Rewrite previous index to point to next in chain.
+                    updateNext = entry.Next;
+                }
+
+                // Push entry back onto free list.
+                entry.Next = eventTable.Free;
+                eventTable.Free = entryIdx;
             }
         }
 
@@ -588,27 +572,15 @@ namespace Robust.Shared.GameObjects
             bool dispatchByReference)
             where TEvent : notnull
         {
-            var enumerator = EntGetReferences(baseType);
-            while (enumerator.MoveNext(out var type))
-            {
-                var compSubs = _entSubscriptions[type.Value]!;
+            var compSubs = _entSubscriptions[baseType.Value]!;
 
-                if (!compSubs.TryGetValue(typeof(TEvent), out var reg))
-                    continue;
+            if (!compSubs.TryGetValue(typeof(TEvent), out var reg))
+                return;
 
-                if (reg.ReferenceEvent != dispatchByReference)
-                    ThrowByRefMisMatch();
+            if (reg.ReferenceEvent != dispatchByReference)
+                ThrowByRefMisMatch();
 
-                reg.Handler(euid, component, ref args);
-            }
-        }
-
-        /// <summary>
-        ///     Enumerates the type's component references, returning the type itself last.
-        /// </summary>
-        private ReferencesEnumerator EntGetReferences(CompIdx type)
-        {
-            return new(type, _comFac.GetRegistration(type).References);
+            reg.Handler(euid, component, ref args);
         }
 
         /// <summary>
@@ -652,7 +624,6 @@ namespace Robust.Shared.GameObjects
         public void Dispose()
         {
             _comFac.ComponentAdded -= ComFacOnComponentAdded;
-            _comFac.ComponentReferenceAdded -= ComFacOnComponentReferenceAdded;
 
             // punishment for use-after-free
             _entMan = null!;
@@ -662,43 +633,6 @@ namespace Robust.Shared.GameObjects
             _entSubscriptionsInv = null!;
         }
 
-        private struct ReferencesEnumerator
-        {
-            private readonly CompIdx _baseType;
-            private readonly ValueList<CompIdx> _list;
-            private readonly int _totalLength;
-            private int _idx;
-
-            public ReferencesEnumerator(CompIdx baseType, ValueList<CompIdx> list)
-            {
-                _baseType = baseType;
-                _list = list;
-                _totalLength = list.Count;
-                _idx = 0;
-            }
-
-            public bool MoveNext(out CompIdx type)
-            {
-                if (_idx >= _totalLength)
-                {
-                    if (_idx++ == _totalLength)
-                    {
-                        type = _baseType;
-                        return true;
-                    }
-
-                    type = default;
-                    return false;
-                }
-
-                type = _list[_idx++];
-                if (type == _baseType)
-                    return MoveNext(out type);
-
-                return true;
-            }
-        }
-
         private struct SubscriptionsEnumerator
         {
             private readonly Type _eventType;

Robust.Shared/GameObjects/EntityManager.Components.cs

@@ -35,9 +35,6 @@ namespace Robust.Shared.GameObjects
 
         private static readonly ComponentState DefaultComponentState = new();
 
-        private readonly Dictionary<EntityUid, Dictionary<ushort, Component>> _netComponents
-            = new(EntityCapacity);
-
         private readonly Dictionary<Type, Dictionary<EntityUid, Component>> _entTraitDict
             = new();
 
@@ -62,7 +59,6 @@ namespace Robust.Shared.GameObjects
 
             FillComponentDict();
             _componentFactory.ComponentAdded += OnComponentAdded;
-            _componentFactory.ComponentReferenceAdded += OnComponentReferenceAdded;
         }
 
         /// <summary>
@@ -71,7 +67,6 @@ namespace Robust.Shared.GameObjects
         /// </summary>
         public void ClearComponents()
         {
-            _netComponents.Clear();
             _entCompIndex.Clear();
             _deleteSet.Clear();
             foreach (var dict in _entTraitDict.Values)
@@ -94,11 +89,6 @@ namespace Robust.Shared.GameObjects
 
         #region Component Management
 
-        private void OnComponentReferenceAdded(ComponentRegistration reg, CompIdx type)
-        {
-            AddComponentRefType(type);
-        }
-
         /// <inheritdoc />
         public int Count<T>() where T : Component
         {
@@ -181,13 +171,13 @@ namespace Robust.Shared.GameObjects
             }
         }
 
-        public Component AddComponent(EntityUid uid, ushort netId)
+        public Component AddComponent(EntityUid uid, ushort netId, MetaDataComponent? meta = null)
         {
             var newComponent = (Component)_componentFactory.GetComponent(netId);
 #pragma warning disable CS0618 // Type or member is obsolete
             newComponent.Owner = uid;
 #pragma warning restore CS0618 // Type or member is obsolete
-            AddComponent(uid, newComponent);
+            AddComponent(uid, newComponent, metadata: meta);
             return newComponent;
         }
 
@@ -255,7 +245,7 @@ namespace Robust.Shared.GameObjects
         }
 
         /// <inheritdoc />
-        public void AddComponent<T>(EntityUid uid, T component, bool overwrite = false) where T : Component
+        public void AddComponent<T>(EntityUid uid, T component, bool overwrite = false, MetaDataComponent? metadata = null) where T : Component
         {
             if (!uid.IsValid() || !EntityExists(uid))
                 throw new ArgumentException($"Entity {uid} is not valid.", nameof(uid));
@@ -273,53 +263,48 @@ namespace Robust.Shared.GameObjects
             }
 #pragma warning restore CS0618 // Type or member is obsolete
 
-            AddComponentInternal(uid, component, overwrite, false);
+            AddComponentInternal(uid, component, overwrite, false, metadata);
         }
 
-        private void AddComponentInternal<T>(EntityUid uid, T component, bool overwrite, bool skipInit) where T : Component
+        private void AddComponentInternal<T>(EntityUid uid, T component, bool overwrite, bool skipInit, MetaDataComponent? metadata = null) where T : Component
+        {
+            // get interface aliases for mapping
+            var reg = _componentFactory.GetRegistration(component);
+            AddComponentInternal(uid, component, reg, overwrite, skipInit, metadata);
+        }
+
+        private void AddComponentInternal<T>(EntityUid uid, T component, ComponentRegistration reg, bool overwrite, bool skipInit, MetaDataComponent? metadata = null) where T : Component
         {
             // We can't use typeof(T) here in case T is just Component
             DebugTools.Assert(component is MetaDataComponent ||
-                GetComponent<MetaDataComponent>(uid).EntityLifeStage < EntityLifeStage.Terminating,
+                              (metadata ?? MetaQuery.GetComponent(uid)).EntityLifeStage < EntityLifeStage.Terminating,
                 $"Attempted to add a {component.GetType().Name} component to an entity ({ToPrettyString(uid)}) while it is terminating");
 
-            // get interface aliases for mapping
-            var reg = _componentFactory.GetRegistration(component);
+            // Check that there is no existing component.
+            var type = reg.Idx;
+            var dict = _entTraitArray[type.Value];
+            DebugTools.Assert(dict != null);
 
-            // Check that there are no overlapping references.
-            foreach (var type in reg.References)
+            if (dict.TryGetValue(uid, out var duplicate))
             {
-                var dict = _entTraitArray[type.Value];
-                if (!dict.TryGetValue(uid, out var duplicate))
-                    continue;
-
                 if (!overwrite && !duplicate.Deleted)
                     throw new InvalidOperationException(
                         $"Component reference type {component.GetType().Name} already occupied by {duplicate}");
 
-                RemoveComponentImmediate(duplicate, uid, false);
+                RemoveComponentImmediate(duplicate, uid, false, metadata);
             }
 
-            // add the component to the grid
-            foreach (var type in reg.References)
-            {
-                _entTraitArray[type.Value].Add(uid, component);
-                _entCompIndex.Add(uid, component);
-            }
+            // actually ADD the component
+            dict.Add(uid, component);
+            _entCompIndex.Add(uid, component);
 
             // add the component to the netId grid
             if (reg.NetID != null)
             {
                 // the main comp grid keeps this in sync
                 var netId = reg.NetID.Value;
-
-                if (!_netComponents.TryGetValue(uid, out var netSet))
-                {
-                    netSet = new Dictionary<ushort, Component>(NetComponentCapacity);
-                    _netComponents.Add(uid, netSet);
-                }
-
-                netSet.Add(netId, component);
+                metadata ??= MetaQuery.GetComponentInternal(uid);
+                metadata.NetComponents.Add(netId, component);
             }
             else
             {
@@ -335,7 +320,7 @@ namespace Robust.Shared.GameObjects
             if (skipInit)
                 return;
 
-            var metadata = GetComponent<MetaDataComponent>(uid);
+            metadata ??= MetaQuery.GetComponentInternal(uid);
 
             if (!metadata.EntityInitialized && !metadata.EntityInitializing)
                 return;
@@ -354,45 +339,48 @@ namespace Robust.Shared.GameObjects
 
         /// <inheritdoc />
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        public bool RemoveComponent<T>(EntityUid uid)
+        public bool RemoveComponent<T>(EntityUid uid, MetaDataComponent? meta = null)
         {
-            return RemoveComponent(uid, typeof(T));
+            return RemoveComponent(uid, typeof(T), meta);
         }
 
         /// <inheritdoc />
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        public bool RemoveComponent(EntityUid uid, Type type)
+        public bool RemoveComponent(EntityUid uid, Type type, MetaDataComponent? meta = null)
         {
             if (!TryGetComponent(uid, type, out var comp))
                 return false;
 
-            RemoveComponentImmediate((Component)comp, uid, false);
+            RemoveComponentImmediate((Component)comp, uid, false, meta);
             return true;
         }
 
         /// <inheritdoc />
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        public bool RemoveComponent(EntityUid uid, ushort netId)
+        public bool RemoveComponent(EntityUid uid, ushort netId, MetaDataComponent? meta = null)
         {
-            if (!TryGetComponent(uid, netId, out var comp))
+            if (!MetaQuery.Resolve(uid, ref meta))
                 return false;
 
-            RemoveComponentImmediate((Component)comp, uid, false);
+            if (!TryGetComponent(uid, netId, out var comp, meta))
+                return false;
+
+            RemoveComponentImmediate((Component)comp, uid, false, meta);
             return true;
         }
 
         /// <inheritdoc />
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        public void RemoveComponent(EntityUid uid, IComponent component)
+        public void RemoveComponent(EntityUid uid, IComponent component, MetaDataComponent? meta = null)
         {
-            RemoveComponent(uid, (Component)component);
+            RemoveComponent(uid, (Component)component, meta);
         }
 
         /// <inheritdoc />
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        public void RemoveComponent(EntityUid uid, Component component)
+        public void RemoveComponent(EntityUid uid, Component component, MetaDataComponent? meta = null)
         {
-            RemoveComponentImmediate(component, uid, false);
+            RemoveComponentImmediate(component, uid, false, meta);
         }
 
         /// <inheritdoc />
@@ -414,9 +402,12 @@ namespace Robust.Shared.GameObjects
 
         /// <inheritdoc />
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        public bool RemoveComponentDeferred(EntityUid uid, ushort netId)
+        public bool RemoveComponentDeferred(EntityUid uid, ushort netId, MetaDataComponent? meta = null)
         {
-            if (!TryGetComponent(uid, netId, out var comp))
+            if (!MetaQuery.Resolve(uid, ref meta))
+                return false;
+
+            if (!TryGetComponent(uid, netId, out var comp, meta))
                 return false;
 
             RemoveComponentDeferred((Component)comp, uid, false);
@@ -452,22 +443,28 @@ namespace Robust.Shared.GameObjects
         }
 
         /// <inheritdoc />
-        public void RemoveComponents(EntityUid uid)
+        public void RemoveComponents(EntityUid uid, MetaDataComponent? meta = null)
         {
+            if (!MetaQuery.Resolve(uid, ref meta))
+                return;
+
             foreach (var comp in InSafeOrder(_entCompIndex[uid]))
             {
-                RemoveComponentImmediate(comp, uid, false);
+                RemoveComponentImmediate(comp, uid, false, meta);
             }
         }
 
         /// <inheritdoc />
-        public void DisposeComponents(EntityUid uid)
+        public void DisposeComponents(EntityUid uid, MetaDataComponent? meta = null)
         {
+            if (!MetaQuery.Resolve(uid, ref meta))
+                return;
+
             foreach (var comp in InSafeOrder(_entCompIndex[uid]))
             {
                 try
                 {
-                    RemoveComponentImmediate(comp, uid, true);
+                    RemoveComponentImmediate(comp, uid, true, meta);
                 }
                 catch (Exception)
                 {
@@ -476,7 +473,6 @@ namespace Robust.Shared.GameObjects
             }
 
             _entCompIndex.Remove(uid);
-            _netComponents.Remove(uid);
         }
 
         private void RemoveComponentDeferred(Component component, EntityUid uid, bool terminating)
@@ -517,7 +513,8 @@ namespace Robust.Shared.GameObjects
 #endif
         }
 
-        private void RemoveComponentImmediate(Component component, EntityUid uid, bool terminating)
+        private void RemoveComponentImmediate(Component component, EntityUid uid, bool terminating,
+            MetaDataComponent? meta)
         {
             if (component.Deleted)
             {
@@ -550,10 +547,7 @@ namespace Robust.Shared.GameObjects
                 _runtimeLog.LogException(e, nameof(RemoveComponentImmediate));
             }
 #endif
-            var eventArgs = new RemovedComponentEventArgs(new ComponentEventArgs(component, uid), terminating);
-            ComponentRemoved?.Invoke(eventArgs);
-            _eventBus.OnComponentRemoved(eventArgs);
-            DeleteComponent(uid, component, terminating);
+            DeleteComponent(uid, component, terminating, meta);
         }
 
         /// <inheritdoc />
@@ -588,39 +582,45 @@ namespace Robust.Shared.GameObjects
                 _runtimeLog.LogException(e, nameof(CullRemovedComponents));
             }
 #endif
-                var eventArgs = new RemovedComponentEventArgs(new ComponentEventArgs(component, uid), false);
-                ComponentRemoved?.Invoke(eventArgs);
-                _eventBus.OnComponentRemoved(eventArgs);
-
                 DeleteComponent(uid, component, false);
             }
 
             _deleteSet.Clear();
         }
 
-        private void DeleteComponent(EntityUid entityUid, Component component, bool terminating)
+        private void DeleteComponent(EntityUid entityUid, Component component, bool terminating, MetaDataComponent? metadata = null)
         {
-            var reg = _componentFactory.GetRegistration(component.GetType());
+            if (!MetaQuery.ResolveInternal(entityUid, ref metadata))
+                return;
 
-            if (!terminating && reg.NetID != null && _netComponents.TryGetValue(entityUid, out var netSet))
+            var eventArgs = new RemovedComponentEventArgs(new ComponentEventArgs(component, entityUid), false, metadata);
+            ComponentRemoved?.Invoke(eventArgs);
+            _eventBus.OnComponentRemoved(eventArgs);
+
+            var reg = _componentFactory.GetRegistration(component);
+            DebugTools.Assert(component.Networked == (reg.NetID != null));
+
+            if (!terminating && reg.NetID != null)
             {
-                if (netSet.Count == 1)
-                    _netComponents.Remove(entityUid);
-                else
-                    netSet.Remove(reg.NetID.Value);
+                if (!metadata.NetComponents.Remove(reg.NetID.Value))
+                    _sawmill.Error($"Entity {ToPrettyString(entityUid, metadata)} did not have {component.GetType().Name} in its networked component dictionary during component deletion.");
 
                 if (component.NetSyncEnabled)
-                    DirtyEntity(entityUid);
+                {
+                    DirtyEntity(entityUid, metadata);
+                    metadata.LastComponentRemoved = _gameTiming.CurTick;
+                }
             }
 
-            foreach (var refType in reg.References)
-            {
-                _entTraitArray[refType.Value].Remove(entityUid);
-            }
+            _entTraitArray[reg.Idx.Value].Remove(entityUid);
 
             // TODO if terminating the entity, maybe defer this?
             // _entCompIndex.Remove(uid) gets called later on anyways.
             _entCompIndex.Remove(entityUid, component);
+
+
+            DebugTools.Assert(_netMan.IsClient // Client side prediction can set LastComponentRemoved to some future tick,
+                              || metadata.EntityLastModifiedTick >= metadata.LastComponentRemoved);
         }
 
         /// <inheritdoc />
@@ -662,23 +662,25 @@ namespace Robust.Shared.GameObjects
 
         /// <inheritdoc />
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        public bool HasComponent(EntityUid uid, ushort netId)
+        public bool HasComponent(EntityUid uid, ushort netId, MetaDataComponent? meta = null)
         {
-            return _netComponents.TryGetValue(uid, out var netSet)
-                   && netSet.ContainsKey(netId);
+            if (!MetaQuery.Resolve(uid, ref meta))
+                return false;
+
+            return meta.NetComponents.ContainsKey(netId);
         }
 
         /// <inheritdoc />
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        public bool HasComponent(EntityUid? uid, ushort netId)
+        public bool HasComponent(EntityUid? uid, ushort netId, MetaDataComponent? meta = null)
         {
             if (!uid.HasValue)
             {
+                DebugTools.AssertNull(meta);
                 return false;
             }
 
-            return _netComponents.TryGetValue(uid.Value, out var netSet)
-                   && netSet.ContainsKey(netId);
+            return HasComponent(uid.Value, netId, meta);
         }
 
         /// <inheritdoc />
@@ -763,9 +765,9 @@ namespace Robust.Shared.GameObjects
         }
 
         /// <inheritdoc />
-        public IComponent GetComponent(EntityUid uid, ushort netId)
+        public IComponent GetComponent(EntityUid uid, ushort netId, MetaDataComponent? meta = null)
         {
-            return _netComponents[uid][netId];
+            return (meta ?? MetaQuery.GetComponentInternal(uid)).NetComponents[netId];
         }
 
         /// <inheritdoc />
@@ -774,7 +776,7 @@ namespace Robust.Shared.GameObjects
             var dict = _entTraitArray[type.Value];
             if (dict.TryGetValue(uid, out var comp))
             {
-                    return comp;
+                return comp;
             }
 
             throw new KeyNotFoundException($"Entity {uid} does not have a component of type {type}");
@@ -879,10 +881,10 @@ namespace Robust.Shared.GameObjects
         }
 
         /// <inheritdoc />
-        public bool TryGetComponent(EntityUid uid, ushort netId, [MaybeNullWhen(false)] out IComponent component)
+        public bool TryGetComponent(EntityUid uid, ushort netId, [MaybeNullWhen(false)] out IComponent component, MetaDataComponent? meta = null)
         {
-            if (_netComponents.TryGetValue(uid, out var netSet)
-                && netSet.TryGetValue(netId, out var comp))
+            if (MetaQuery.TryGetComponentInternal(uid, out var metadata)
+                && metadata.NetComponents.TryGetValue(netId, out var comp))
             {
                 component = comp;
                 return true;
@@ -894,23 +896,16 @@ namespace Robust.Shared.GameObjects
 
         /// <inheritdoc />
         public bool TryGetComponent([NotNullWhen(true)] EntityUid? uid, ushort netId,
-            [MaybeNullWhen(false)] out IComponent component)
+            [MaybeNullWhen(false)] out IComponent component, MetaDataComponent? meta = null)
         {
             if (!uid.HasValue)
             {
+                DebugTools.AssertNull(meta);
                 component = default;
                 return false;
             }
 
-            if (_netComponents.TryGetValue(uid.Value, out var netSet)
-                && netSet.TryGetValue(netId, out var comp))
-            {
-                component = comp;
-                return true;
-            }
-
-            component = default;
-            return false;
+            return TryGetComponent(uid.Value, netId, out component, meta);
         }
 
         public EntityQuery<TComp1> GetEntityQuery<TComp1>() where TComp1 : Component
@@ -978,17 +973,18 @@ namespace Robust.Shared.GameObjects
         }
 
         /// <inheritdoc />
-        public NetComponentEnumerable GetNetComponents(EntityUid uid)
+        public NetComponentEnumerable GetNetComponents(EntityUid uid, MetaDataComponent? meta = null)
         {
-            return new NetComponentEnumerable(_netComponents[uid]);
+            meta ??= MetaQuery.GetComponentInternal(uid);
+            return new NetComponentEnumerable(meta.NetComponents);
         }
 
         /// <inheritdoc />
-        public NetComponentEnumerable? GetNetComponentsOrNull(EntityUid uid)
+        public NetComponentEnumerable? GetNetComponentsOrNull(EntityUid uid, MetaDataComponent? meta = null)
         {
-            return _netComponents.TryGetValue(uid, out var data)
-                    ? new NetComponentEnumerable(data)
-                    : null;
+            return MetaQuery.Resolve(uid, ref meta)
+                ? new NetComponentEnumerable(meta.NetComponents)
+                : null;
         }
 
         #region Join Functions

Robust.Shared/GameObjects/EntityManager.Network.cs

@@ -16,7 +16,7 @@ public partial class EntityManager
     /// Inverse lookup for net entities.
     /// Regular lookup uses MetadataComponent.
     /// </summary>
-    protected readonly Dictionary<NetEntity, EntityUid> NetEntityLookup = new(EntityCapacity);
+    protected readonly Dictionary<NetEntity, (EntityUid, MetaDataComponent)> NetEntityLookup = new(EntityCapacity);
 
     /// <summary>
     /// Clears an old inverse lookup for a particular entityuid.
@@ -34,7 +34,7 @@ public partial class EntityManager
     internal void SetNetEntity(EntityUid uid, NetEntity netEntity, MetaDataComponent component)
     {
         DebugTools.Assert(!NetEntityLookup.ContainsKey(netEntity));
-        NetEntityLookup[netEntity] = uid;
+        NetEntityLookup[netEntity] = (uid, component);
         component.NetEntity = netEntity;
     }
 
@@ -64,7 +64,7 @@ public partial class EntityManager
     {
         if (NetEntityLookup.TryGetValue(nEntity, out var went))
         {
-            entity = went;
+            entity = went.Item1;
             return true;
         }
 
@@ -72,6 +72,21 @@ public partial class EntityManager
         return false;
     }
 
+    /// <inheritdoc />
+    public bool TryGetEntityData(NetEntity nEntity, [NotNullWhen(true)] out EntityUid? entity, [NotNullWhen(true)] out MetaDataComponent? meta)
+    {
+        if (NetEntityLookup.TryGetValue(nEntity, out var went))
+        {
+            entity = went.Item1;
+            meta = went.Item2;
+            return true;
+        }
+
+        entity = null;
+        meta = null;
+        return false;
+    }
+
     /// <inheritdoc />
     public bool TryGetEntity(NetEntity? nEntity, [NotNullWhen(true)] out EntityUid? entity)
     {
@@ -141,7 +156,15 @@ public partial class EntityManager
         if (nEntity == NetEntity.Invalid)
             return EntityUid.Invalid;
 
-        return NetEntityLookup.GetValueOrDefault(nEntity);
+        if (!NetEntityLookup.TryGetValue(nEntity, out var tuple))
+            return EntityUid.Invalid;
+
+        return tuple.Item1;
+    }
+
+    public (EntityUid, MetaDataComponent) GetEntityData(NetEntity nEntity)
+    {
+        return NetEntityLookup[nEntity];
     }
 
     /// <inheritdoc />

Robust.Shared/GameObjects/EntityManager.Spawn.cs

@@ -95,7 +95,7 @@ public partial class EntityManager
         ComponentRegistry? overrides = null)
     {
         uid = null;
-        if (!_xformQuery.Resolve(target, ref xform))
+        if (!TransformQuery.Resolve(target, ref xform))
             return false;
 
         if (!xform.ParentUid.IsValid())
@@ -157,7 +157,7 @@ public partial class EntityManager
 
     public EntityUid SpawnNextToOrDrop(string? protoName, EntityUid target, TransformComponent? xform = null, ComponentRegistry? overrides = null)
     {
-        xform ??= _xformQuery.GetComponent(target);
+        xform ??= TransformQuery.GetComponent(target);
         if (!xform.ParentUid.IsValid())
             return Spawn(protoName);
 
@@ -181,7 +181,7 @@ public partial class EntityManager
              || !container.Insert(uid, this))
         {
 
-            xform ??= _xformQuery.GetComponent(containerUid);
+            xform ??= TransformQuery.GetComponent(containerUid);
             if (xform.ParentUid.IsValid())
                 _xforms.PlaceNextToOrDrop(uid, containerUid, targetXform: xform);
         }

Robust.Shared/GameObjects/EntityManager.cs

@@ -1,17 +1,18 @@
-using Prometheus;
-using Robust.Shared.Log;
-using Robust.Shared.Map;
-using Robust.Shared.Profiling;
-using Robust.Shared.Prototypes;
-using Robust.Shared.Serialization.Manager;
-using Robust.Shared.Timing;
-using Robust.Shared.Utility;
 using System;
 using System.Collections.Generic;
 using System.Diagnostics.CodeAnalysis;
 using System.Linq;
 using System.Runtime.CompilerServices;
+using Prometheus;
+using Robust.Shared.Log;
+using Robust.Shared.Map;
+using Robust.Shared.Network;
+using Robust.Shared.Profiling;
+using Robust.Shared.Prototypes;
+using Robust.Shared.Serialization.Manager;
 using Robust.Shared.Serialization.Markdown.Mapping;
+using Robust.Shared.Timing;
+using Robust.Shared.Utility;
 
 namespace Robust.Shared.GameObjects
 {
@@ -32,13 +33,14 @@ namespace Robust.Shared.GameObjects
         [IoC.Dependency] private readonly IGameTiming _gameTiming = default!;
         [IoC.Dependency] private readonly ISerializationManager _serManager = default!;
         [IoC.Dependency] private readonly ProfManager _prof = default!;
+        [IoC.Dependency] private readonly INetManager _netMan = default!;
 
         // I feel like PJB might shed me for putting a system dependency here, but its required for setting entity
         // positions on spawn....
         private SharedTransformSystem _xforms = default!;
 
-        protected EntityQuery<MetaDataComponent> MetaQuery;
-        private EntityQuery<TransformComponent> _xformQuery;
+        public EntityQuery<MetaDataComponent> MetaQuery;
+        public EntityQuery<TransformComponent> TransformQuery;
 
         #endregion Dependencies
 
@@ -86,6 +88,9 @@ namespace Robust.Shared.GameObjects
 
         private string _xformName = string.Empty;
 
+        private ComponentRegistration _metaReg = default!;
+        private ComponentRegistration _xformReg = default!;
+
         private SharedMapSystem _mapSystem = default!;
 
         private ISawmill _sawmill = default!;
@@ -112,7 +117,9 @@ namespace Robust.Shared.GameObjects
             _eventBus = new EntityEventBus(this);
 
             InitializeComponents();
-            _xformName = _componentFactory.GetComponentName(typeof(TransformComponent));
+            _metaReg = _componentFactory.GetRegistration(typeof(MetaDataComponent));
+            _xformReg = _componentFactory.GetRegistration(typeof(TransformComponent));
+            _xformName = _xformReg.Name;
             _sawmill = LogManager.GetSawmill("entity");
             _resolveSawmill = LogManager.GetSawmill("resolve");
 
@@ -234,7 +241,7 @@ namespace Robust.Shared.GameObjects
             _mapSystem = System<SharedMapSystem>();
             _xforms = System<SharedTransformSystem>();
             MetaQuery = GetEntityQuery<MetaDataComponent>();
-            _xformQuery = GetEntityQuery<TransformComponent>();
+            TransformQuery = GetEntityQuery<TransformComponent>();
         }
 
         public virtual void Shutdown()
@@ -251,7 +258,6 @@ namespace Robust.Shared.GameObjects
         public virtual void Cleanup()
         {
             _componentFactory.ComponentAdded -= OnComponentAdded;
-            _componentFactory.ComponentReferenceAdded -= OnComponentReferenceAdded;
             ShuttingDown = true;
             FlushEntities();
             _entitySystemManager.Clear();
@@ -318,7 +324,7 @@ namespace Robust.Shared.GameObjects
         public virtual EntityUid CreateEntityUninitialized(string? prototypeName, EntityCoordinates coordinates, ComponentRegistry? overrides = null)
         {
             var newEntity = CreateEntity(prototypeName, overrides);
-            _xforms.SetCoordinates(newEntity, _xformQuery.GetComponent(newEntity), coordinates, unanchor: false);
+            _xforms.SetCoordinates(newEntity, TransformQuery.GetComponent(newEntity), coordinates, unanchor: false);
             return newEntity;
         }
 
@@ -326,7 +332,7 @@ namespace Robust.Shared.GameObjects
         public virtual EntityUid CreateEntityUninitialized(string? prototypeName, MapCoordinates coordinates, ComponentRegistry? overrides = null)
         {
             var newEntity = CreateEntity(prototypeName, overrides);
-            var transform = _xformQuery.GetComponent(newEntity);
+            var transform = TransformQuery.GetComponent(newEntity);
 
             if (coordinates.MapId == MapId.Nullspace)
             {
@@ -365,18 +371,8 @@ namespace Robust.Shared.GameObjects
         public virtual void DirtyEntity(EntityUid uid, MetaDataComponent? metadata = null)
         {
             // We want to retrieve MetaDataComponent even if its Deleted flag is set.
-            if (metadata == null)
-            {
-                if (!_entTraitArray[CompIdx.ArrayIndex<MetaDataComponent>()].TryGetValue(uid, out var component))
-                    throw new KeyNotFoundException($"Entity {uid} does not exist, cannot dirty it.");
-                metadata = (MetaDataComponent)component;
-            }
-            else
-            {
-#pragma warning disable CS0618
-                DebugTools.Assert(metadata.Owner == uid);
-#pragma warning restore CS0618
-            }
+            if (!MetaQuery.ResolveInternal(uid, ref metadata))
+                return;
 
             if (metadata.EntityLastModifiedTick == _gameTiming.CurTick)
                 return;
@@ -447,7 +443,7 @@ namespace Robust.Shared.GameObjects
             EntityUid uid,
             MetaDataComponent metadata)
         {
-            var transform = _xformQuery.GetComponent(uid);
+            var transform = TransformQuery.GetComponent(uid);
             metadata.EntityLifeStage = EntityLifeStage.Terminating;
 
             try
@@ -479,7 +475,7 @@ namespace Robust.Shared.GameObjects
         {
             // Note about this method: #if EXCEPTION_TOLERANCE is not used here because we're gonna it in the future...
             var netEntity = GetNetEntity(uid, metadata);
-            var transform = _xformQuery.GetComponent(uid);
+            var transform = TransformQuery.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).
@@ -545,20 +541,23 @@ namespace Robust.Shared.GameObjects
             NetEntityLookup.Remove(netEntity);
         }
 
-        public virtual void QueueDeleteEntity(EntityUid uid)
+        public virtual void QueueDeleteEntity(EntityUid? uid)
         {
-            if (!QueuedDeletionsSet.Add(uid))
+            if (uid == null)
                 return;
 
-            QueuedDeletions.Enqueue(uid);
-            EntityQueueDeleted?.Invoke(uid);
+            if (!QueuedDeletionsSet.Add(uid.Value))
+                return;
+
+            QueuedDeletions.Enqueue(uid.Value);
+            EntityQueueDeleted?.Invoke(uid.Value);
         }
 
         public bool IsQueuedForDeletion(EntityUid uid) => QueuedDeletionsSet.Contains(uid);
 
         public bool EntityExists(EntityUid uid)
         {
-            return _entTraitArray[CompIdx.ArrayIndex<MetaDataComponent>()].ContainsKey(uid);
+            return MetaQuery.HasComponentInternal(uid);
         }
 
         public bool EntityExists(EntityUid? uid)
@@ -577,12 +576,12 @@ namespace Robust.Shared.GameObjects
 
         public bool Deleted(EntityUid uid)
         {
-            return !_entTraitArray[CompIdx.ArrayIndex<MetaDataComponent>()].TryGetValue(uid, out var comp) || ((MetaDataComponent) comp).EntityDeleted;
+            return !MetaQuery.TryGetComponentInternal(uid, out var comp) || comp.EntityDeleted;
         }
 
         public bool Deleted([NotNullWhen(false)] EntityUid? uid)
         {
-            return !uid.HasValue || !_entTraitArray[CompIdx.ArrayIndex<MetaDataComponent>()].TryGetValue(uid.Value, out var comp) || ((MetaDataComponent) comp).EntityDeleted;
+            return !uid.HasValue || !MetaQuery.TryGetComponentInternal(uid.Value, out var comp) || comp.EntityDeleted;
         }
 
         /// <summary>
@@ -644,10 +643,12 @@ namespace Robust.Shared.GameObjects
 
             Entities.Add(uid);
             // add the required MetaDataComponent directly.
-            AddComponentInternal(uid, metadata, false, false);
+            AddComponentInternal(uid, metadata, _metaReg, false, true, metadata);
 
             // allocate the required TransformComponent
-            AddComponent<TransformComponent>(uid);
+            var xformComp = Unsafe.As<TransformComponent>(_componentFactory.GetComponent(_xformReg));
+            xformComp.Owner = uid;
+            AddComponentInternal(uid, xformComp, false, true, metadata);
 
             return uid;
         }
@@ -705,7 +706,7 @@ namespace Robust.Shared.GameObjects
                 StartEntity(entity);
 
                 // If the map we're initializing the entity on is initialized, run map init on it.
-                if (_mapManager.IsMapInitialized(mapId ?? _xformQuery.GetComponent(entity).MapID))
+                if (_mapManager.IsMapInitialized(mapId ?? TransformQuery.GetComponent(entity).MapID))
                     RunMapInit(entity, meta);
             }
             catch (Exception e)
@@ -738,23 +739,34 @@ namespace Robust.Shared.GameObjects
         }
 
         /// <inheritdoc />
-        public virtual EntityStringRepresentation ToPrettyString(EntityUid uid)
+        [return: NotNullIfNotNull("uid")]
+        public virtual EntityStringRepresentation? ToPrettyString(EntityUid? uid)
         {
             // We want to retrieve the MetaData component even if it is deleted.
-            if (!_entTraitArray[CompIdx.ArrayIndex<MetaDataComponent>()].TryGetValue(uid, out var component))
-                return new EntityStringRepresentation(uid, true);
+            if (uid == null)
+                return null;
+
+            if (!_entTraitArray[CompIdx.ArrayIndex<MetaDataComponent>()].TryGetValue(uid.Value, out var component))
+                return new EntityStringRepresentation(uid.Value, true);
 
             var metadata = (MetaDataComponent) component;
 
-            return ToPrettyString(uid, metadata);
+            return ToPrettyString(uid.Value, metadata);
         }
 
         /// <inheritdoc />
-        public EntityStringRepresentation ToPrettyString(NetEntity netEntity)
+        [return: NotNullIfNotNull("netEntity")]
+        public EntityStringRepresentation? ToPrettyString(NetEntity? netEntity)
         {
             return ToPrettyString(GetEntity(netEntity));
         }
 
+        public EntityStringRepresentation ToPrettyString(EntityUid uid)
+            => ToPrettyString((EntityUid?) uid).Value;
+
+        public EntityStringRepresentation ToPrettyString(NetEntity netEntity)
+            => ToPrettyString((NetEntity?) netEntity).Value;
+
         private EntityStringRepresentation ToPrettyString(EntityUid uid, MetaDataComponent metadata)
         {
             return new EntityStringRepresentation(uid, metadata.EntityDeleted, metadata.EntityName, metadata.EntityPrototype?.ID);

Robust.Shared/GameObjects/EntitySystem.Proxy.cs

@@ -61,7 +61,7 @@ public partial class EntitySystem
     [MethodImpl(MethodImplOptions.AggressiveInlining)]
     protected bool Deleted(EntityUid uid, MetaDataComponent? metaData = null)
     {
-        if (!Resolve(uid, ref metaData, false))
+        if (!EntityManager.MetaQuery.Resolve(uid, ref metaData, false))
             return true;
 
         return metaData.EntityDeleted;
@@ -73,7 +73,7 @@ public partial class EntitySystem
     [MethodImpl(MethodImplOptions.AggressiveInlining)]
     protected bool TerminatingOrDeleted(EntityUid uid, MetaDataComponent? metaData = null)
     {
-        if (!Resolve(uid, ref metaData, false))
+        if (!EntityManager.MetaQuery.Resolve(uid, ref metaData, false))
             return true;
 
         return metaData.EntityLifeStage >= EntityLifeStage.Terminating;
@@ -104,7 +104,7 @@ public partial class EntitySystem
     [MethodImpl(MethodImplOptions.AggressiveInlining)]
     protected EntityLifeStage LifeStage(EntityUid uid, MetaDataComponent? metaData = null)
     {
-        if (!Resolve(uid, ref metaData, false))
+        if (!EntityManager.MetaQuery.Resolve(uid, ref metaData, false))
             throw CompNotFound<MetaDataComponent>(uid);
 
         return metaData.EntityLifeStage;
@@ -169,7 +169,7 @@ public partial class EntitySystem
     [MethodImpl(MethodImplOptions.AggressiveInlining)]
     protected bool TryLifeStage(EntityUid uid, [NotNullWhen(true)] out EntityLifeStage? lifeStage, MetaDataComponent? metaData = null)
     {
-        if (!Resolve(uid, ref metaData))
+        if (!EntityManager.MetaQuery.Resolve(uid, ref metaData, false))
         {
             lifeStage = null;
             return false;
@@ -227,7 +227,7 @@ public partial class EntitySystem
     [MethodImpl(MethodImplOptions.AggressiveInlining)]
     protected string Name(EntityUid uid, MetaDataComponent? metaData = null)
     {
-        if(!Resolve(uid, ref metaData, false))
+        if (!EntityManager.MetaQuery.Resolve(uid, ref metaData, false))
             throw CompNotFound<MetaDataComponent>(uid);
 
         return metaData.EntityName;
@@ -240,7 +240,7 @@ public partial class EntitySystem
     [MethodImpl(MethodImplOptions.AggressiveInlining)]
     protected string Description(EntityUid uid, MetaDataComponent? metaData = null)
     {
-        if(!Resolve(uid, ref metaData, false))
+        if (!EntityManager.MetaQuery.Resolve(uid, ref metaData, false))
             throw CompNotFound<MetaDataComponent>(uid);
 
         return metaData.EntityDescription;
@@ -253,7 +253,7 @@ public partial class EntitySystem
     [MethodImpl(MethodImplOptions.AggressiveInlining)]
     protected EntityPrototype? Prototype(EntityUid uid, MetaDataComponent? metaData = null)
     {
-        if (!Resolve(uid, ref metaData, false))
+        if (!EntityManager.MetaQuery.Resolve(uid, ref metaData, false))
             throw CompNotFound<MetaDataComponent>(uid);
 
         return metaData.EntityPrototype;
@@ -265,7 +265,7 @@ public partial class EntitySystem
     /// <exception cref="KeyNotFoundException">Thrown when the entity doesn't exist.</exception>
     protected GameTick LastModifiedTick(EntityUid uid, MetaDataComponent? metaData = null)
     {
-        if (!Resolve(uid, ref metaData, false))
+        if (!EntityManager.MetaQuery.Resolve(uid, ref metaData, false))
             throw CompNotFound<MetaDataComponent>(uid);
 
         return metaData.EntityLastModifiedTick;
@@ -278,7 +278,7 @@ public partial class EntitySystem
     [MethodImpl(MethodImplOptions.AggressiveInlining)]
     protected bool Paused(EntityUid uid, MetaDataComponent? metaData = null)
     {
-        if (!Resolve(uid, ref metaData, false))
+        if (!EntityManager.MetaQuery.Resolve(uid, ref metaData, false))
             throw CompNotFound<MetaDataComponent>(uid);
 
         return metaData.EntityPaused;
@@ -291,7 +291,7 @@ public partial class EntitySystem
     [MethodImpl(MethodImplOptions.AggressiveInlining)]
     protected void SetPaused(EntityUid uid, bool paused, MetaDataComponent? metaData = null)
     {
-        if (!Resolve(uid, ref metaData, false))
+        if (!EntityManager.MetaQuery.Resolve(uid, ref metaData, false))
             throw CompNotFound<MetaDataComponent>(uid);
 
         EntityManager.EntitySysManager.GetEntitySystem<MetaDataSystem>().SetEntityPaused(uid, paused, metaData);
@@ -302,12 +302,12 @@ public partial class EntitySystem
     /// </summary>
     /// <returns>Whether the operation succeeded.</returns>
     [MethodImpl(MethodImplOptions.AggressiveInlining)]
-    protected bool TryDirty(EntityUid uid)
+    protected bool TryDirty(EntityUid uid, MetaDataComponent? metaData = null)
     {
-        if (!Exists(uid))
+        if (!EntityManager.MetaQuery.Resolve(uid, ref metaData, false))
             return false;
 
-        DirtyEntity(uid);
+        DirtyEntity(uid, metaData);
         return true;
     }
 
@@ -318,7 +318,7 @@ public partial class EntitySystem
     [MethodImpl(MethodImplOptions.AggressiveInlining)]
     protected bool TryName(EntityUid uid, [NotNullWhen(true)] out string? name, MetaDataComponent? metaData = null)
     {
-        if (!Resolve(uid, ref metaData, false))
+        if (!EntityManager.MetaQuery.Resolve(uid, ref metaData, false))
         {
             name = null;
             return false;
@@ -335,7 +335,7 @@ public partial class EntitySystem
     [MethodImpl(MethodImplOptions.AggressiveInlining)]
     protected bool TryDescription(EntityUid uid, [NotNullWhen(true)] out string? description, MetaDataComponent? metaData = null)
     {
-        if (!Resolve(uid, ref metaData, false))
+        if (!EntityManager.MetaQuery.Resolve(uid, ref metaData, false))
         {
             description = null;
             return false;
@@ -352,7 +352,7 @@ public partial class EntitySystem
     [MethodImpl(MethodImplOptions.AggressiveInlining)]
     protected bool TryPrototype(EntityUid uid, [NotNullWhen(true)] out EntityPrototype? prototype, MetaDataComponent? metaData = null)
     {
-        if (!Resolve(uid, ref metaData, false))
+        if (!EntityManager.MetaQuery.Resolve(uid, ref metaData, false))
         {
             prototype = null;
             return false;
@@ -369,7 +369,7 @@ public partial class EntitySystem
     [MethodImpl(MethodImplOptions.AggressiveInlining)]
     protected bool TryLastModifiedTick(EntityUid uid, [NotNullWhen(true)] out GameTick? lastModifiedTick, MetaDataComponent? metaData = null)
     {
-        if (!Resolve(uid, ref metaData, false))
+        if (!EntityManager.MetaQuery.Resolve(uid, ref metaData, false))
         {
             lastModifiedTick = null;
             return false;
@@ -386,7 +386,7 @@ public partial class EntitySystem
     [MethodImpl(MethodImplOptions.AggressiveInlining)]
     protected bool TryPaused(EntityUid uid, [NotNullWhen(true)] out bool? paused, MetaDataComponent? metaData = null)
     {
-        if (!Resolve(uid, ref metaData, false))
+        if (!EntityManager.MetaQuery.Resolve(uid, ref metaData, false))
         {
             paused = null;
             return false;
@@ -398,18 +398,30 @@ public partial class EntitySystem
 
     /// <inheritdoc cref="IEntityManager.ToPrettyString"/>
     [MethodImpl(MethodImplOptions.AggressiveInlining)]
-    protected EntityStringRepresentation ToPrettyString(EntityUid uid)
+    [return: NotNullIfNotNull("uid")]
+    protected EntityStringRepresentation? ToPrettyString(EntityUid? uid)
     {
         return EntityManager.ToPrettyString(uid);
     }
 
     /// <inheritdoc cref="IEntityManager.ToPrettyString"/>
     [MethodImpl(MethodImplOptions.AggressiveInlining)]
-    protected EntityStringRepresentation ToPrettyString(NetEntity netEntity)
+    [return: NotNullIfNotNull("netEntity")]
+    protected EntityStringRepresentation? ToPrettyString(NetEntity? netEntity)
     {
         return EntityManager.ToPrettyString(netEntity);
     }
 
+    /// <inheritdoc cref="IEntityManager.ToPrettyString"/>
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    protected EntityStringRepresentation ToPrettyString(EntityUid uid)
+        => ToPrettyString((EntityUid?) uid).Value;
+
+    /// <inheritdoc cref="IEntityManager.ToPrettyString"/>
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    protected EntityStringRepresentation ToPrettyString(NetEntity netEntity)
+        => ToPrettyString((NetEntity?) netEntity).Value;
+
     #endregion
 
     #region Component Get
@@ -446,6 +458,20 @@ public partial class EntitySystem
         return EntityManager.TryGetComponent(uid, out comp);
     }
 
+    /// <inheritdoc cref="IEntityManager.TryGetComponent&lt;T&gt;(EntityUid, out T)"/>
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    protected bool TryComp(EntityUid uid, [NotNullWhen(true)] out TransformComponent? comp)
+    {
+        return EntityManager.TransformQuery.TryGetComponent(uid, out comp);
+    }
+
+    /// <inheritdoc cref="IEntityManager.TryGetComponent&lt;T&gt;(EntityUid, out T)"/>
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    protected bool TryComp(EntityUid uid, [NotNullWhen(true)] out MetaDataComponent? comp)
+    {
+        return EntityManager.MetaQuery.TryGetComponent(uid, out comp);
+    }
+
     /// <inheritdoc cref="IEntityManager.TryGetComponent&lt;T&gt;(EntityUid?, out T)"/>
     [MethodImpl(MethodImplOptions.AggressiveInlining)]
     protected bool TryComp<T>([NotNullWhen(true)] EntityUid? uid, [NotNullWhen(true)] out T? comp)
@@ -459,6 +485,30 @@ public partial class EntitySystem
         return EntityManager.TryGetComponent(uid.Value, out comp);
     }
 
+    /// <inheritdoc cref="IEntityManager.TryGetComponent&lt;T&gt;(EntityUid?, out T)"/>
+    protected bool TryComp([NotNullWhen(true)] EntityUid? uid, [NotNullWhen(true)] out TransformComponent? comp)
+    {
+        if (!uid.HasValue)
+        {
+            comp = default;
+            return false;
+        }
+
+        return EntityManager.TransformQuery.TryGetComponent(uid.Value, out comp);
+    }
+
+    /// <inheritdoc cref="IEntityManager.TryGetComponent&lt;T&gt;(EntityUid?, out T)"/>
+    protected bool TryComp([NotNullWhen(true)] EntityUid? uid, [NotNullWhen(true)] out MetaDataComponent? comp)
+    {
+        if (!uid.HasValue)
+        {
+            comp = default;
+            return false;
+        }
+
+        return EntityManager.MetaQuery.TryGetComponent(uid.Value, out comp);
+    }
+
     /// <inheritdoc cref="IEntityManager.GetComponents"/>
     [MethodImpl(MethodImplOptions.AggressiveInlining)]
     protected IEnumerable<IComponent> AllComps(EntityUid uid)
@@ -480,7 +530,7 @@ public partial class EntitySystem
     [MethodImpl(MethodImplOptions.AggressiveInlining)]
     protected TransformComponent Transform(EntityUid uid)
     {
-        return EntityManager.GetComponent<TransformComponent>(uid);
+        return EntityManager.TransformQuery.GetComponent(uid);
     }
 
     /// <summary>
@@ -490,7 +540,20 @@ public partial class EntitySystem
     [MethodImpl(MethodImplOptions.AggressiveInlining)]
     protected MetaDataComponent MetaData(EntityUid uid)
     {
-        return EntityManager.GetComponent<MetaDataComponent>(uid);
+        return EntityManager.MetaQuery.GetComponent(uid);
+    }
+
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    protected (EntityUid, MetaDataComponent)  GetEntityData(NetEntity nuid)
+    {
+        return EntityManager.GetEntityData(nuid);
+    }
+
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    protected bool TryGetEntityData(NetEntity nuid, [NotNullWhen(true)] out EntityUid? uid,
+        [NotNullWhen(true)] out MetaDataComponent? meta)
+    {
+        return EntityManager.TryGetEntityData(nuid, out uid, out meta);
     }
 
     #endregion
@@ -651,7 +714,7 @@ public partial class EntitySystem
 
     /// <inheritdoc cref="IEntityManager.QueueDeleteEntity(EntityUid)" />
     [MethodImpl(MethodImplOptions.AggressiveInlining)]
-    protected void QueueDel(EntityUid uid)
+    protected void QueueDel(EntityUid? uid)
     {
         EntityManager.QueueDeleteEntity(uid);
     }
@@ -897,9 +960,9 @@ public partial class EntitySystem
     #region NetEntities
 
     [MethodImpl(MethodImplOptions.AggressiveInlining)]
-    protected bool IsClientSide(EntityUid entity)
+    protected bool IsClientSide(EntityUid entity, MetaDataComponent? meta = null)
     {
-        return EntityManager.IsClientSide(entity);
+        return EntityManager.IsClientSide(entity, meta);
     }
 
     [MethodImpl(MethodImplOptions.AggressiveInlining)]

Robust.Shared/GameObjects/EntitySystem.Resolve.cs

@@ -32,6 +32,22 @@ namespace Robust.Shared.GameObjects
             return found;
         }
 
+        /// <inheritdoc cref="Resolve{TComp}"/>
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        protected bool Resolve(EntityUid uid, [NotNullWhen(true)] ref MetaDataComponent? component,
+            bool logMissing = true)
+        {
+            return EntityManager.MetaQuery.Resolve(uid, ref component);
+        }
+
+        /// <inheritdoc cref="Resolve{TComp}"/>
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        protected bool Resolve(EntityUid uid, [NotNullWhen(true)] ref TransformComponent? component,
+            bool logMissing = true)
+        {
+            return EntityManager.TransformQuery.Resolve(uid, ref component);
+        }
+
         /// <summary>
         ///     Resolves the components on the entity for the null component references.
         /// </summary>

Robust.Shared/GameObjects/EntityUid.cs

@@ -190,8 +190,10 @@ namespace Robust.Shared.GameObjects
 
         // This might seem useless, but it allows you to retrieve remote entities that don't exist on the client.
         [ViewVariables]
-        private EntityUid Uid => this;
+        private EntityUid _uid => this;
 
+        [ViewVariables]
+        private NetEntity _netId => IoCManager.Resolve<IEntityManager>().GetNetEntity(this);
         #endregion
     }
 }

Robust.Shared/GameObjects/IComponentFactory.cs

@@ -52,7 +52,6 @@ namespace Robust.Shared.GameObjects
     public interface IComponentFactory
     {
         event Action<ComponentRegistration> ComponentAdded;
-        event Action<ComponentRegistration, CompIdx> ComponentReferenceAdded;
         event Action<string> ComponentIgnoreAdded;
 
         /// <summary>
@@ -156,7 +155,7 @@ namespace Robust.Shared.GameObjects
         /// </exception>
         [Pure]
         string GetComponentName(Type componentType);
-        
+
         /// <summary>
         ///     Gets the name of a component, throwing an exception if it does not exist.
         /// </summary>

Robust.Shared/GameObjects/IEntityManager.Components.cs

@@ -49,7 +49,7 @@ namespace Robust.Shared.GameObjects
         /// <summary>
         ///     Adds a Component with a given network id to an entity.
         /// </summary>
-        Component AddComponent(EntityUid uid, ushort netId);
+        Component AddComponent(EntityUid uid, ushort netId, MetaDataComponent? meta = null);
 
         /// <summary>
         ///     Adds an uninitialized Component type to an entity.
@@ -70,7 +70,7 @@ namespace Robust.Shared.GameObjects
         /// <param name="uid">Entity being modified.</param>
         /// <param name="component">Component to add.</param>
         /// <param name="overwrite">Should it overwrite existing components?</param>
-        void AddComponent<T>(EntityUid uid, T component, bool overwrite = false) where T : Component;
+        void AddComponent<T>(EntityUid uid, T component, bool overwrite = false, MetaDataComponent? metadata = null) where T : Component;
 
         /// <summary>
         ///     Removes the component with the specified reference type,
@@ -78,7 +78,7 @@ namespace Robust.Shared.GameObjects
         /// </summary>
         /// <typeparam name="T">The component reference type to remove.</typeparam>
         /// <param name="uid">Entity UID to modify.</param>
-        bool RemoveComponent<T>(EntityUid uid);
+        bool RemoveComponent<T>(EntityUid uid, MetaDataComponent? meta = null);
 
         /// <summary>
         ///     Removes the component with a specified type.
@@ -86,7 +86,7 @@ namespace Robust.Shared.GameObjects
         /// <param name="uid">Entity UID to modify.</param>
         /// <param name="type">A trait or component type to check for.</param>
         /// <returns>Returns false if the entity did not have the specified component.</returns>
-        bool RemoveComponent(EntityUid uid, Type type);
+        bool RemoveComponent(EntityUid uid, Type type, MetaDataComponent? meta = null);
 
         /// <summary>
         ///     Removes the component with a specified network ID.
@@ -94,14 +94,14 @@ namespace Robust.Shared.GameObjects
         /// <param name="uid">Entity UID to modify.</param>
         /// <param name="netID">Network ID of the component to remove.</param>
         /// <returns>Returns false if the entity did not have the specified component.</returns>
-        bool RemoveComponent(EntityUid uid, ushort netID);
+        bool RemoveComponent(EntityUid uid, ushort netID, MetaDataComponent? meta = null);
 
         /// <summary>
         ///     Removes the specified component. Throws if the given component does not belong to the entity.
         /// </summary>
         /// <param name="uid">Entity UID to modify.</param>
         /// <param name="component">Component to remove.</param>
-        void RemoveComponent(EntityUid uid, IComponent component);
+        void RemoveComponent(EntityUid uid, IComponent component, MetaDataComponent? meta = null);
 
         /// <summary>
         ///     Immediately shuts down a component, but defers the removal and deletion until the end of the tick.
@@ -125,7 +125,7 @@ namespace Robust.Shared.GameObjects
         /// <param name="uid">Entity UID to modify.</param>
         /// <param name="netID">Network ID of the component to remove.</param>
         /// <returns>Returns false if the entity did not have the specified component.</returns>
-        bool RemoveComponentDeferred(EntityUid uid, ushort netID);
+        bool RemoveComponentDeferred(EntityUid uid, ushort netID, MetaDataComponent? meta = null);
 
         /// <summary>
         ///     Immediately shuts down a component, but defers the removal and deletion until the end of the tick.
@@ -147,7 +147,7 @@ namespace Robust.Shared.GameObjects
         ///     Removes all components from an entity, except the required components.
         /// </summary>
         /// <param name="uid">Entity UID to modify.</param>
-        void RemoveComponents(EntityUid uid);
+        void RemoveComponents(EntityUid uid, MetaDataComponent? meta = null);
 
         /// <summary>
         ///     Removes ALL components from an entity. This includes the required components,
@@ -155,7 +155,7 @@ namespace Robust.Shared.GameObjects
         ///     used when deleting an entity.
         /// </summary>
         /// <param name="uid">Entity UID to modify.</param>
-        void DisposeComponents(EntityUid uid);
+        void DisposeComponents(EntityUid uid, MetaDataComponent? meta = null);
 
         /// <summary>
         ///     Checks if the entity has a component type.
@@ -187,7 +187,7 @@ namespace Robust.Shared.GameObjects
         /// <param name="uid">Entity UID to check.</param>
         /// <param name="type">A trait or component type to check for.</param>
         /// <returns>True if the entity has the component type, otherwise false.</returns>
-        bool HasComponent(EntityUid ?uid, Type type);
+        bool HasComponent(EntityUid? uid, Type type);
 
         /// <summary>
         ///     Checks if the entity has a component with a given network ID. This does not check
@@ -196,7 +196,7 @@ namespace Robust.Shared.GameObjects
         /// <param name="uid">Entity UID to check.</param>
         /// <param name="netId">Network ID to check for.</param>
         /// <returns>True if the entity has a component with the given network ID, otherwise false.</returns>
-        bool HasComponent(EntityUid uid, ushort netId);
+        bool HasComponent(EntityUid uid, ushort netId, MetaDataComponent? meta = null);
 
         /// <summary>
         ///     Checks if the entity has a component with a given network ID. This does not check
@@ -205,7 +205,7 @@ namespace Robust.Shared.GameObjects
         /// <param name="uid">Entity UID to check.</param>
         /// <param name="netId">Network ID to check for.</param>
         /// <returns>True if the entity has a component with the given network ID, otherwise false.</returns>
-        bool HasComponent(EntityUid? uid, ushort netId);
+        bool HasComponent(EntityUid? uid, ushort netId, MetaDataComponent? meta = null);
 
         /// <summary>
         ///     This method will always return a component for a certain entity, adding it if it's not there already.
@@ -255,7 +255,7 @@ namespace Robust.Shared.GameObjects
         /// <param name="uid">Entity UID to look on.</param>
         /// <param name="netId">Network ID of the component to retrieve.</param>
         /// <returns>The component with the specified network id.</returns>
-        IComponent GetComponent(EntityUid uid, ushort netId);
+        IComponent GetComponent(EntityUid uid, ushort netId, MetaDataComponent? meta = null);
 
         /// <summary>
         ///     Returns the component of a specific type, even if it has been marked for deletion.
@@ -318,7 +318,7 @@ namespace Robust.Shared.GameObjects
         /// <param name="netId">Component Network ID to check for.</param>
         /// <param name="component">Component with the specified network id.</param>
         /// <returns>If the component existed in the entity.</returns>
-        bool TryGetComponent(EntityUid uid, ushort netId, [NotNullWhen(true)] out IComponent? component);
+        bool TryGetComponent(EntityUid uid, ushort netId, [NotNullWhen(true)] out IComponent? component, MetaDataComponent? meta = null);
 
         /// <summary>
         ///     Returns the component with a specified network ID. This does not check
@@ -328,7 +328,7 @@ namespace Robust.Shared.GameObjects
         /// <param name="netId">Component Network ID to check for.</param>
         /// <param name="component">Component with the specified network id.</param>
         /// <returns>If the component existed in the entity.</returns>
-        bool TryGetComponent([NotNullWhen(true)] EntityUid? uid, ushort netId, [NotNullWhen(true)] out IComponent? component);
+        bool TryGetComponent([NotNullWhen(true)] EntityUid? uid, ushort netId, [NotNullWhen(true)] out IComponent? component, MetaDataComponent? meta = null);
 
         /// <summary>
         /// Returns a cached struct enumerator with the specified component.
@@ -364,7 +364,7 @@ namespace Robust.Shared.GameObjects
         /// </summary>
         /// <param name="uid">Entity UID to look on.</param>
         /// <returns>All components that have a network ID.</returns>
-        NetComponentEnumerable GetNetComponents(EntityUid uid);
+        NetComponentEnumerable GetNetComponents(EntityUid uid, MetaDataComponent? meta = null);
 
         /// <summary>
         ///     Returns ALL networked components on an entity, including deleted ones. Returns null if the entity does
@@ -372,7 +372,7 @@ namespace Robust.Shared.GameObjects
         /// </summary>
         /// <param name="uid">Entity UID to look on.</param>
         /// <returns>All components that have a network ID.</returns>
-        public NetComponentEnumerable? GetNetComponentsOrNull(EntityUid uid);
+        public NetComponentEnumerable? GetNetComponentsOrNull(EntityUid uid, MetaDataComponent? meta = null);
 
         /// <summary>
         ///     Gets a component state.

Robust.Shared/GameObjects/IEntityManager.Network.cs

@@ -22,6 +22,12 @@ public partial interface IEntityManager
     /// </summary>
     public bool TryGetEntity(NetEntity? nEntity, [NotNullWhen(true)] out EntityUid? entity);
 
+    /// <summary>
+    /// Tries to returns the corresponding local <see cref="EntityUid"/> along with the metdata component.
+    /// </summary>
+    public bool TryGetEntityData(NetEntity nEntity, [NotNullWhen(true)] out EntityUid? entity,
+        [NotNullWhen(true)] out MetaDataComponent? meta);
+
     /// <summary>
     /// TryGet version of <see cref="GetNetEntity"/>
     /// </summary>
@@ -191,4 +197,10 @@ public partial interface IEntityManager
     public NetCoordinates[] GetNetCoordinatesArray(EntityCoordinates[] entities);
 
     public NetCoordinates?[] GetNetCoordinatesArray(EntityCoordinates?[] entities);
+
+    /// <summary>
+    /// Returns the corresponding local <see cref="EntityUid"/> along with the metdata component.
+    /// throws an exception if the net entity does not exist.
+    /// </summary>
+    (EntityUid, MetaDataComponent) GetEntityData(NetEntity nEntity);
 }

Robust.Shared/GameObjects/IEntityManager.cs

@@ -87,7 +87,7 @@ namespace Robust.Shared.GameObjects
 
         public void Dirty(EntityUid uid, Component component, MetaDataComponent? meta = null);
 
-        public void QueueDeleteEntity(EntityUid uid);
+        public void QueueDeleteEntity(EntityUid? uid);
 
         public bool IsQueuedForDeletion(EntityUid uid);
 
@@ -129,6 +129,23 @@ namespace Robust.Shared.GameObjects
         /// </summary>
         EntityStringRepresentation ToPrettyString(EntityUid uid);
 
+        /// <summary>
+        /// Returns a string representation of an entity with various information regarding it.
+        /// </summary>
+        EntityStringRepresentation ToPrettyString(NetEntity netEntity);
+
+        /// <summary>
+        /// Returns a string representation of an entity with various information regarding it.
+        /// </summary>
+        [return: NotNullIfNotNull("uid")]
+        EntityStringRepresentation? ToPrettyString(EntityUid? uid);
+
+        /// <summary>
+        /// Returns a string representation of an entity with various information regarding it.
+        /// </summary>
+        [return: NotNullIfNotNull("netEntity")]
+        EntityStringRepresentation? ToPrettyString(NetEntity? netEntity);
+
         #endregion Entity Management
 
         /// <summary>

Robust.Shared/GameObjects/NetEntity.cs

@@ -4,6 +4,7 @@ using Robust.Shared.IoC;
 using Robust.Shared.Prototypes;
 using Robust.Shared.Serialization;
 using Robust.Shared.Timing;
+using Robust.Shared.Utility;
 using Robust.Shared.ViewVariables;
 
 namespace Robust.Shared.GameObjects;
@@ -47,7 +48,14 @@ public readonly struct NetEntity : IEquatable<NetEntity>, IComparable<NetEntity>
     /// </summary>
     public static NetEntity Parse(ReadOnlySpan<char> uid)
     {
-        return new NetEntity(int.Parse(uid));
+        if (uid[0] != 'c')
+            return new NetEntity(int.Parse(uid));
+
+        if (uid.Length == 1)
+            throw new FormatException($"'c' is not a valid NetEntity");
+
+        var id = int.Parse(uid.Slice(1));
+        return new NetEntity(id | ClientEntity);
     }
 
     public static bool TryParse(ReadOnlySpan<char> uid, out NetEntity entity)
@@ -84,7 +92,7 @@ public readonly struct NetEntity : IEquatable<NetEntity>, IComparable<NetEntity>
     public override bool Equals(object? obj)
     {
         if (ReferenceEquals(null, obj)) return false;
-        return obj is EntityUid id && Equals(id);
+        return obj is NetEntity id && Equals(id);
     }
 
     /// <inheritdoc />
@@ -121,6 +129,9 @@ public readonly struct NetEntity : IEquatable<NetEntity>, IComparable<NetEntity>
     /// <inheritdoc />
     public override string ToString()
     {
+        if (IsClientSide())
+            return $"c{Id & ~ClientEntity}";
+
         return Id.ToString();
     }
 
@@ -135,6 +146,14 @@ public readonly struct NetEntity : IEquatable<NetEntity>, IComparable<NetEntity>
         ReadOnlySpan<char> format,
         IFormatProvider? provider)
     {
+        if (IsClientSide())
+        {
+            return FormatHelpers.TryFormatInto(
+                destination,
+                out charsWritten,
+                $"c{Id & ~ClientEntity}");
+        }
+
         return Id.TryFormat(destination, out charsWritten);
     }
 
@@ -214,7 +233,7 @@ public readonly struct NetEntity : IEquatable<NetEntity>, IComparable<NetEntity>
     }
 
     [ViewVariables]
-    private EntityUid Uid
+    private EntityUid _uid
     {
         get
         {
@@ -222,5 +241,7 @@ public readonly struct NetEntity : IEquatable<NetEntity>, IComparable<NetEntity>
         }
     }
 
+    [ViewVariables] private NetEntity _netId => this;
+
     #endregion
 }

Robust.Shared/GameObjects/Systems/EntityLookupSystem.cs

@@ -54,9 +54,11 @@ public enum LookupFlags : byte
     /// </summary>
     Sensors = 1 << 6,
 
-    Uncontained = Dynamic | Static | Sundries,
+    Uncontained = Dynamic | Static | Sundries | Sensors,
 
     StaticSundries = Static | Sundries,
+
+    All = Contained | Dynamic | Static | Sundries | Sensors
 }
 
 /// <summary>
@@ -90,7 +92,7 @@ public sealed partial class EntityLookupSystem : EntitySystem
     /// <summary>
     /// Returns all non-grid entities. Consider using your own flags if you wish for a faster query.
     /// </summary>
-    public const LookupFlags DefaultFlags = LookupFlags.Contained | LookupFlags.Dynamic | LookupFlags.Static | LookupFlags.Sundries;
+    public const LookupFlags DefaultFlags = LookupFlags.All;
 
     public override void Initialize()
     {

Robust.Shared/GameObjects/Systems/SharedEyeSystem.cs

@@ -8,6 +8,20 @@ public abstract class SharedEyeSystem : EntitySystem
 {
     [Dependency] protected readonly SharedTransformSystem TransformSystem = default!;
 
+    /// <summary>
+    /// Refreshes all values for IEye with the component.
+    /// </summary>
+    public void UpdateEye(EyeComponent component)
+    {
+        if (component._eye == null)
+            return;
+
+        component._eye.Offset = component.Offset;
+        component._eye.DrawFov = component.DrawFov;
+        component._eye.Rotation = component.Rotation;
+        component._eye.Zoom = component.Zoom;
+    }
+
     public void SetOffset(EntityUid uid, Vector2 value, EyeComponent? eyeComponent = null)
     {
         if (!Resolve(uid, ref eyeComponent))

Robust.Shared/GameObjects/Systems/SharedGridFixtureSystem.cs

@@ -152,7 +152,10 @@ namespace Robust.Shared.GameObjects
                     poly,
                     MapGridHelpers.CollisionGroup,
                     MapGridHelpers.CollisionGroup,
-                    true);
+                    true)
+                {
+                    Owner = uid
+                };
 #pragma warning restore CS0618
 
                 newFixtures.Add(($"grid_chunk-{bounds.Left}-{bounds.Bottom}", newFixture));

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

@@ -495,7 +495,7 @@ public abstract partial class SharedTransformSystem
                     throw new InvalidOperationException($"Attempted to parent entity {ToPrettyString(uid)} to non-existent entity {value.EntityId}");
                 }
 
-                if (newParent.LifeStage > ComponentLifeStage.Running || LifeStage(value.EntityId) > EntityLifeStage.MapInitialized)
+                if (newParent.LifeStage >= ComponentLifeStage.Stopping || LifeStage(value.EntityId) >= EntityLifeStage.Terminating)
                 {
                     DetachParentToNull(uid, xform);
                     if (_netMan.IsServer || IsClientSide(uid))

Robust.Shared/Network/Messages/MsgState.cs

@@ -95,6 +95,8 @@ namespace Robust.Shared.Network.Messages
             MsgSize = buffer.LengthBytes;
         }
 
+        public bool ForceSendReliably;
+
         /// <summary>
         ///     Whether this state message is large enough to warrant being sent reliably.
         ///     This is only valid after
@@ -103,7 +105,7 @@ namespace Robust.Shared.Network.Messages
         public bool ShouldSendReliably()
         {
             DebugTools.Assert(_hasWritten, "Attempted to determine sending method before determining packet size.");
-            return MsgSize > ReliableThreshold;
+            return ForceSendReliably || MsgSize > ReliableThreshold;
         }
 
         public override NetDeliveryMethod DeliveryMethod

Robust.Shared/Physics/Collision/PhysicsHull.cs

@@ -28,7 +28,7 @@ public record struct PhysicsHull()
         e.Normalize();
 
         // discard points left of e and find point furthest to the right of e
-        var rightPoints = new Vector2[PhysicsConstants.MaxPolygonVertices];
+        Span<Vector2> rightPoints = stackalloc Vector2[PhysicsConstants.MaxPolygonVertices];
         var rightCount = 0;
 
         var bestIndex = 0;

Robust.Shared/Physics/DynamicTree.cs

@@ -24,6 +24,8 @@ using System.Collections.Generic;
 using System.Diagnostics;
 using System.Numerics;
 using System.Runtime.CompilerServices;
+using System.Runtime.InteropServices;
+using System.Runtime.Intrinsics;
 using JetBrains.Annotations;
 using Robust.Shared.Maths;
 
@@ -131,7 +133,7 @@ namespace Robust.Shared.Physics
 
             aabb ??= _extractAabb(item);
 
-            if (HasNaNs(aabb.Value))
+            if (aabb.Value.HasNan())
             {
                 _nodeLookup[item] = DynamicTree.Proxy.Free;
                 return true;
@@ -179,28 +181,25 @@ namespace Robust.Shared.Physics
         [MethodImpl(MethodImplOptions.NoInlining)]
         public bool Update(in T item, Box2? newBox = null)
         {
-            if (!TryGetProxy(item, out var proxy))
-            {
+            ref var proxy = ref CollectionsMarshal.GetValueRefOrNullRef(_nodeLookup, item);
+            if (Unsafe.IsNullRef(ref proxy))
                 return false;
-            }
 
             newBox ??= _extractAabb(item);
 
-            if (HasNaNs(newBox.Value))
+            if (newBox.Value.HasNan())
             {
                 if (proxy == DynamicTree.Proxy.Free)
-                {
                     return false;
-                }
 
                 _b2Tree.DestroyProxy(proxy);
-                _nodeLookup[item] = DynamicTree.Proxy.Free;
+                proxy = DynamicTree.Proxy.Free;
                 return true;
             }
 
             if (proxy == DynamicTree.Proxy.Free)
             {
-                _nodeLookup[item] = _b2Tree.CreateProxy(newBox.Value, item);
+                proxy = _b2Tree.CreateProxy(newBox.Value, item);
                 return true;
             }
 
@@ -331,36 +330,30 @@ namespace Robust.Shared.Physics
         public void AddOrUpdate(T item, Box2? aabb = null)
         {
             aabb ??= _extractAabb(item);
-            if (!_nodeLookup.TryGetValue(item, out var proxy))
+
+            ref var proxy = ref CollectionsMarshal.GetValueRefOrAddDefault(_nodeLookup, item, out var exists);
+            if (!exists)
             {
-                _nodeLookup[item] = HasNaNs(aabb.Value) ? DynamicTree.Proxy.Free : _b2Tree.CreateProxy(aabb.Value, item);
+                proxy = aabb.Value.HasNan() ? DynamicTree.Proxy.Free : _b2Tree.CreateProxy(aabb.Value, item);
                 return;
             }
 
-            if (HasNaNs(aabb.Value))
+            if (aabb.Value.HasNan())
             {
                 if (proxy == DynamicTree.Proxy.Free)
                     return;
 
                 _b2Tree.DestroyProxy(proxy);
-                _nodeLookup[item] = DynamicTree.Proxy.Free;
+                proxy = DynamicTree.Proxy.Free;
                 return;
             }
 
             if (proxy == DynamicTree.Proxy.Free)
-                _nodeLookup[item] = _b2Tree.CreateProxy(aabb.Value, item);
+                proxy = _b2Tree.CreateProxy(aabb.Value, item);
             else
                 _b2Tree.MoveProxy(proxy, aabb.Value, Vector2.Zero);
         }
 
-        private static bool HasNaNs(in Box2 box)
-        {
-            return float.IsNaN(box.Left)
-                   || float.IsNaN(box.Top)
-                   || float.IsNaN(box.Bottom)
-                   || float.IsNaN(box.Right);
-        }
-
         [Conditional("DEBUG_DYNAMIC_TREE")]
         [Conditional("DEBUG_DYNAMIC_TREE_ASSERTS")]
         [DebuggerNonUserCode]

Robust.Shared/Physics/Dynamics/Fixture.cs

@@ -23,6 +23,7 @@
 using System;
 using System.Collections.Generic;
 using System.Numerics;
+using Robust.Shared.GameObjects;
 using Robust.Shared.Maths;
 using Robust.Shared.Physics.Collision.Shapes;
 using Robust.Shared.Physics.Components;
@@ -31,6 +32,7 @@ using Robust.Shared.Physics.Systems;
 using Robust.Shared.Serialization;
 using Robust.Shared.Serialization.Manager.Attributes;
 using Robust.Shared.Serialization.TypeSerializers.Implementations.Custom;
+using Robust.Shared.Utility;
 using Robust.Shared.ViewVariables;
 
 namespace Robust.Shared.Physics.Dynamics
@@ -50,6 +52,9 @@ namespace Robust.Shared.Physics.Dynamics
         [DataField("shape")]
         public IPhysShape Shape { get; private set; } = new PhysShapeAabb();
 
+        [NonSerialized]
+        public EntityUid Owner;
+
         /// <summary>
         /// All of the other fixtures this fixture has a contact with.
         /// </summary>
@@ -176,7 +181,10 @@ namespace Robust.Shared.Physics.Dynamics
         {
             if (other == null) return false;
 
-            return Equivalent(other);
+            // Owner field shouldn't be required, fixtures on other entities shouldn't be getting compared to each other.
+            // This is mainly here because it might've intruded some physics bugs, so this is here just in case.
+            DebugTools.Assert(Owner == other.Owner);
+            return Equivalent(other) && Owner == other.Owner;
         }
     }
 

Robust.Shared/Physics/Systems/FixtureSystem.cs

@@ -98,6 +98,7 @@ namespace Robust.Shared.Physics.Systems
             }
 
             manager.Fixtures.Add(fixtureId, fixture);
+            fixture.Owner = uid;
 
             if (body.CanCollide && Resolve(uid, ref xform))
             {
@@ -205,12 +206,14 @@ namespace Robust.Shared.Physics.Systems
             // hence we'll just make sure its body is set and SharedBroadphaseSystem will deal with it later.
             if (Resolve(uid, ref body, false))
             {
-                foreach (var id in component.Fixtures.Keys)
+                foreach (var (id, fixture) in component.Fixtures)
                 {
                     if (string.IsNullOrEmpty(id))
                     {
                         throw new InvalidOperationException($"Tried to setup fixture on init for {ToPrettyString(uid)} with no ID!");
                     }
+
+                    fixture.Owner = uid;
                 }
 
                 // Make sure all the right stuff is set on the body
@@ -235,6 +238,10 @@ namespace Robust.Shared.Physics.Systems
                 Log.Error($"Tried to apply fixture state for an entity without physics: {ToPrettyString(uid)}");
                 return;
             }
+            foreach (var fixture in component.Fixtures.Values)
+            {
+                fixture.Owner = uid;
+            }
 
             var toAddFixtures = new ValueList<(string Id, Fixture Fixture)>();
             var toRemoveFixtures = new ValueList<(string Id, Fixture Fixture)>();
@@ -248,6 +255,7 @@ namespace Robust.Shared.Physics.Systems
                 var newFixture = new Fixture();
                 fixture.CopyTo(newFixture);
                 newFixtures.Add(id, newFixture);
+                newFixture.Owner = uid;
             }
 
             TransformComponent? xform = null;

Robust.Shared/Prototypes/EntProtoId.cs

@@ -0,0 +1,27 @@
+using System;
+using Robust.Shared.Serialization;
+using Robust.Shared.Serialization.TypeSerializers.Implementations;
+
+namespace Robust.Shared.Prototypes;
+
+/// <summary>
+///     Wrapper type for an <see cref="EntityPrototype"/> with a given id.
+/// </summary>
+/// <param name="Id">The id of the prototype.</param>
+/// <remarks>
+///     This will be automatically validated by <see cref="EntProtoIdSerializer"/> if used in data fields.
+/// </remarks>
+/// <remarks><seealso cref="ProtoId{T}"/> for a wrapper of other prototype kinds.</remarks>
+[Serializable, NetSerializable]
+public readonly record struct EntProtoId(string Id)
+{
+    public static implicit operator string(EntProtoId protoId)
+    {
+        return protoId.Id;
+    }
+
+    public static implicit operator EntProtoId(string id)
+    {
+        return new EntProtoId(id);
+    }
+}

Robust.Shared/Prototypes/EntityCategoryPrototype.cs

@@ -0,0 +1,25 @@
+using Robust.Shared.Serialization.Manager.Attributes;
+
+namespace Robust.Shared.Prototypes;
+
+/// <summary>
+/// Prototype that represents game entities.
+/// </summary>
+[Prototype("entityCategory")]
+public sealed class EntityCategoryPrototype : IPrototype
+{
+    [IdDataField]
+    public string ID { get; private set; } = default!;
+
+    /// <summary>
+    /// Localized name of the category, for use in entity spawn menus.
+    /// </summary>
+    [DataField("name")]
+    public string? Name { get; private set; }
+
+    /// <summary>
+    /// Localized description of the category, for use in entity spawn menus.
+    /// </summary>
+    [DataField("description")]
+    public string? Description { get; private set; }
+}

Robust.Shared/Prototypes/EntityPrototype.cs

@@ -4,7 +4,6 @@ using System.Diagnostics.CodeAnalysis;
 using Robust.Shared.GameObjects;
 using Robust.Shared.IoC;
 using Robust.Shared.Localization;
-using Robust.Shared.Log;
 using Robust.Shared.Map;
 using Robust.Shared.Maths;
 using Robust.Shared.Serialization;
@@ -12,6 +11,7 @@ using Robust.Shared.Serialization.Manager;
 using Robust.Shared.Serialization.Manager.Attributes;
 using Robust.Shared.Serialization.Markdown.Mapping;
 using Robust.Shared.Serialization.TypeSerializers.Implementations.Custom.Prototype.Array;
+using Robust.Shared.Serialization.TypeSerializers.Implementations.Custom.Prototype.Set;
 using Robust.Shared.ViewVariables;
 
 namespace Robust.Shared.Prototypes
@@ -27,6 +27,9 @@ namespace Robust.Shared.Prototypes
 
         private static readonly Dictionary<string, string> LocPropertiesDefault = new();
 
+        [ValidatePrototypeId<EntityCategoryPrototype>]
+        private const string HideCategory = "hideSpawnMenu";
+
         // LOCALIZATION NOTE:
         // Localization-related properties in here are manually localized in LocalizationManager.
         // As such, they should NOT be inherited to avoid confusing the system.
@@ -57,6 +60,10 @@ namespace Robust.Shared.Prototypes
         [DataField("suffix")]
         public string? SetSuffix { get; private set; }
 
+        [DataField("categories")]
+        [AlwaysPushInheritance]
+        public HashSet<string> Categories = new();
+
         [ViewVariables]
         public IReadOnlyDictionary<string, string> LocProperties => _locPropertiesSet ?? LocPropertiesDefault;
 
@@ -92,8 +99,11 @@ namespace Robust.Shared.Prototypes
         [ViewVariables]
         [NeverPushInheritance]
         [DataField("noSpawn")]
+        [Obsolete("Use the HideSpawnMenu")]
         public bool NoSpawn { get; private set; }
 
+        public bool HideSpawnMenu => Categories.Contains(HideCategory);
+
         [DataField("placement")]
         private EntityPlacementProperties PlacementProperties = new();
 

Robust.Shared/Prototypes/IPrototypeManager.cs

@@ -82,6 +82,12 @@ public interface IPrototypeManager
     /// </exception>
     T Index<T>(string id) where T : class, IPrototype;
 
+    /// <inheritdoc cref="Index{T}(string)"/>
+    EntityPrototype Index(EntProtoId id);
+
+    /// <inheritdoc cref="Index{T}(string)"/>
+    T Index<T>(ProtoId<T> id) where T : class, IPrototype;
+
     /// <summary>
     /// Index for a <see cref="IPrototype"/> by ID.
     /// </summary>
@@ -95,9 +101,21 @@ public interface IPrototypeManager
     /// </summary>
     bool HasIndex<T>(string id) where T : class, IPrototype;
 
+    /// <inheritdoc cref="HasIndex{T}(string)"/>
+    bool HasIndex(EntProtoId id);
+
+    /// <inheritdoc cref="HasIndex{T}(string)"/>
+    bool HasIndex<T>(ProtoId<T> id) where T : class, IPrototype;
+
     bool TryIndex<T>(string id, [NotNullWhen(true)] out T? prototype) where T : class, IPrototype;
     bool TryIndex(Type kind, string id, [NotNullWhen(true)] out IPrototype? prototype);
 
+    /// <inheritdoc cref="TryIndex{T}(string, out T)"/>
+    bool TryIndex(EntProtoId id, [NotNullWhen(true)] out EntityPrototype? prototype);
+
+    /// <inheritdoc cref="TryIndex{T}(string, out T)"/>
+    bool TryIndex<T>(ProtoId<T> id, [NotNullWhen(true)] out T? prototype) where T : class, IPrototype;
+
     bool HasMapping<T>(string id);
     bool TryGetMapping(Type kind, string id, [NotNullWhen(true)] out MappingDataNode? mappings);
 

Robust.Shared/Prototypes/ProtoId.cs

@@ -0,0 +1,25 @@
+using Robust.Shared.Serialization.TypeSerializers.Implementations.Generic;
+
+namespace Robust.Shared.Prototypes;
+
+/// <summary>
+///     Wrapper type for a prototype id of kind <see cref="T"/>.
+/// </summary>
+/// <param name="Id">The id of the prototype.</param>
+/// <typeparam name="T">The kind of prototype to wrap, for example <see cref="TileAliasPrototype"/></typeparam>
+/// <remarks>
+///     This will be automatically validated by <see cref="ProtoIdSerializer{T}"/> if used in data fields.
+/// </remarks>
+/// <remarks><seealso cref="EntProtoId"/> for an <see cref="EntityPrototype"/> alias.</remarks>
+public readonly record struct ProtoId<T>(string Id) where T : class, IPrototype
+{
+    public static implicit operator string(ProtoId<T> protoId)
+    {
+        return protoId.Id;
+    }
+
+    public static implicit operator ProtoId<T>(string id)
+    {
+        return new ProtoId<T>(id);
+    }
+}

Robust.Shared/Prototypes/PrototypeManager.cs

@@ -175,7 +175,7 @@ namespace Robust.Shared.Prototypes
                 throw new InvalidOperationException("No prototypes have been loaded yet.");
             return _kinds.Keys;
         }
-        
+
         /// <inheritdoc />
         public T Index<T>(string id) where T : class, IPrototype
         {
@@ -194,6 +194,18 @@ namespace Robust.Shared.Prototypes
             }
         }
 
+        /// <inheritdoc />
+        public EntityPrototype Index(EntProtoId id)
+        {
+            return Index<EntityPrototype>(id.Id);
+        }
+
+        /// <inheritdoc />
+        public T Index<T>(ProtoId<T> id) where T : class, IPrototype
+        {
+            return Index<T>(id.Id);
+        }
+
         /// <inheritdoc />
         public IPrototype Index(Type kind, string id)
         {
@@ -582,6 +594,18 @@ namespace Robust.Shared.Prototypes
             return index.Instances.ContainsKey(id);
         }
 
+        /// <inheritdoc />
+        public bool HasIndex(EntProtoId id)
+        {
+            return HasIndex<EntityPrototype>(id.Id);
+        }
+
+        /// <inheritdoc />
+        public bool HasIndex<T>(ProtoId<T> id) where T : class, IPrototype
+        {
+            return HasIndex<T>(id.Id);
+        }
+
         /// <inheritdoc />
         public bool TryIndex<T>(string id, [NotNullWhen(true)] out T? prototype) where T : class, IPrototype
         {
@@ -601,6 +625,18 @@ namespace Robust.Shared.Prototypes
             return index.Instances.TryGetValue(id, out prototype);
         }
 
+        /// <inheritdoc />
+        public bool TryIndex(EntProtoId id, [NotNullWhen(true)] out EntityPrototype? prototype)
+        {
+            return TryIndex(id.Id, out prototype);
+        }
+
+        /// <inheritdoc />
+        public bool TryIndex<T>(ProtoId<T> id, [NotNullWhen(true)] out T? prototype) where T : class, IPrototype
+        {
+            return TryIndex(id.Id, out prototype);
+        }
+
         /// <inheritdoc />
         public bool HasMapping<T>(string id)
         {

Robust.Shared/Serialization/Manager/Attributes/DataFieldAttribute.cs

@@ -9,7 +9,11 @@ namespace Robust.Shared.Serialization.Manager.Attributes
     [Virtual]
     public class DataFieldAttribute : DataFieldBaseAttribute
     {
-        public readonly string Tag;
+        /// <summary>
+        ///     The name of this field in YAML.
+        ///     If null, the name of the C# field will be used instead, with the first letter lowercased.
+        /// </summary>
+        public string? Tag { get; internal set; }
 
         /// <summary>
         ///     Whether or not this field being mapped is required for the component to function.
@@ -18,14 +22,13 @@ namespace Robust.Shared.Serialization.Manager.Attributes
         /// </summary>
         public readonly bool Required;
 
-
-        public DataFieldAttribute(string tag, bool readOnly = false, int priority = 1, bool required = false, bool serverOnly = false, Type? customTypeSerializer = null) : base(readOnly, priority, serverOnly, customTypeSerializer)
+        public DataFieldAttribute(string? tag = null, bool readOnly = false, int priority = 1, bool required = false, bool serverOnly = false, Type? customTypeSerializer = null) : base(readOnly, priority, serverOnly, customTypeSerializer)
         {
             Tag = tag;
             Required = required;
         }
 
-        public override string ToString()
+        public override string? ToString()
         {
             return Tag;
         }

Robust.Shared/Serialization/Manager/Definition/DataDefinition.cs

@@ -57,6 +57,17 @@ namespace Robust.Shared.Serialization.Manager.Definition
             IsRecord = isRecord;
 
             var fieldDefs = GetFieldDefinitions(manager, isRecord);
+            foreach (var field in fieldDefs)
+            {
+                if (field.Attribute is not DataFieldAttribute attribute ||
+                    attribute.Tag != null)
+                {
+                    continue;
+                }
+
+                var name = field.FieldInfo.Name.AsSpan();
+                attribute.Tag = $"{char.ToLowerInvariant(name[0])}{name[1..]}";
+            }
 
             var dataFields = fieldDefs
                 .Select(f => f.Attribute)
@@ -65,7 +76,7 @@ namespace Robust.Shared.Serialization.Manager.Definition
             Duplicates = dataFields
                 .Where(f =>
                     dataFields.Count(df => df.Tag == f.Tag) > 1)
-                .Select(f => f.Tag)
+                .Select(f => f.Tag!)
                 .Distinct()
                 .ToArray();
 

Robust.Shared/Serialization/Manager/SerializationManager.Composition.cs

@@ -112,14 +112,40 @@ public partial class SerializationManager
         }, (node, this));
     }
 
-    private SequenceDataNode PushInheritanceSequence(SequenceDataNode child, SequenceDataNode _)
+    private SequenceDataNode PushInheritanceSequence(SequenceDataNode child, SequenceDataNode parent)
     {
-        return child; //todo implement different inheritancebehaviours for yamlfield
+        //todo implement different inheritancebehaviours for yamlfield
+        // I have NFI what this comment means.
+
+        var result = new SequenceDataNode(child.Count + parent.Count);
+        foreach (var entry in parent)
+        {
+            result.Add(entry);
+        }
+        foreach (var entry in child)
+        {
+            result.Add(entry);
+        }
+
+        return result;
     }
 
-    private MappingDataNode PushInheritanceMapping(MappingDataNode child, MappingDataNode _)
+    private MappingDataNode PushInheritanceMapping(MappingDataNode child, MappingDataNode parent)
     {
-        return child; //todo implement different inheritancebehaviours for yamlfield
+        //todo implement different inheritancebehaviours for yamlfield
+        // I have NFI what this comment means.
+
+        var result = new MappingDataNode(child.Count + parent.Count);
+        foreach (var (k, v) in parent)
+        {
+            result[k] = v;
+        }
+        foreach (var (k, v) in child)
+        {
+            result[k] = v;
+        }
+
+        return result;
     }
 
     private MappingDataNode PushInheritanceDefinition(MappingDataNode child, MappingDataNode parent,
@@ -134,7 +160,8 @@ public partial class SerializationManager
 
             if (field.Attribute is DataFieldAttribute dfa)
             {
-                if(!processedTags.Add(dfa.Tag)) continue; //tag was already processed, probably because we are using the same tag in an include
+                // tag is set on data definition creation
+                if(!processedTags.Add(dfa.Tag!)) continue; //tag was already processed, probably because we are using the same tag in an include
                 var key = new ValueDataNode(dfa.Tag);
                 if (parent.TryGetValue(key, out var parentValue))
                 {

Robust.Shared/Serialization/Manager/SerializationManager.SerializerProvider.cs

@@ -2,7 +2,6 @@
 using System.Collections.Generic;
 using System.Collections.Immutable;
 using System.Diagnostics.CodeAnalysis;
-using System.Linq;
 using System.Reflection;
 using System.Runtime.CompilerServices;
 using System.Threading;
@@ -16,14 +15,11 @@ namespace Robust.Shared.Serialization.Manager;
 
 public sealed partial class SerializationManager
 {
-    [Obsolete]
-    public static Type[] SerializerInterfaces => _serializerInterfaces.ToArray();
-
     /// <summary>
     ///     <see cref="CopyCreatorIndex"/>
     ///     <see cref="CopierIndex"/>
     /// </summary>
-    private static readonly ImmutableArray<Type> _serializerInterfaces = new[]
+    private static readonly ImmutableArray<Type> SerializerInterfaces = new[]
     {
         typeof(ITypeReader<,>),
         typeof(ITypeInheritanceHandler<,>),
@@ -34,12 +30,12 @@ public sealed partial class SerializationManager
     }.ToImmutableArray();
 
     /// <summary>
-    ///     <see cref="_serializerInterfaces"/>
+    ///     <see cref="SerializerInterfaces"/>
     /// </summary>
     private const int CopyCreatorIndex = 3;
 
     /// <summary>
-    ///     <see cref="_serializerInterfaces"/>
+    ///     <see cref="SerializerInterfaces"/>
     /// </summary>
     private const int CopierIndex = 4;
 
@@ -94,7 +90,7 @@ public sealed partial class SerializationManager
     {
         public SerializerProvider(IEnumerable<Type> typeSerializers)
         {
-            foreach (var serializerInterface in _serializerInterfaces)
+            foreach (var serializerInterface in SerializerInterfaces)
             {
                 RegisterSerializerInterface(serializerInterface);
             }
@@ -107,7 +103,7 @@ public sealed partial class SerializationManager
 
         public SerializerProvider()
         {
-            foreach (var serializerInterface in _serializerInterfaces)
+            foreach (var serializerInterface in SerializerInterfaces)
             {
                 RegisterSerializerInterface(serializerInterface);
             }
@@ -120,7 +116,7 @@ public sealed partial class SerializationManager
         /// <summary>
         ///     Type serializers indexed by their type serializer and type
         ///     that they serialize.
-        ///     <see cref="_serializerInterfaces"/> for the first index.
+        ///     <see cref="SerializationManager.SerializerInterfaces"/> for the first index.
         /// </summary>
         private (object? Regular, object? Generic)[]?[] _typeSerializersArray = new (object? Regular, object? Generic)[]?[] { };
 
@@ -221,7 +217,7 @@ public sealed partial class SerializationManager
                         {
                             var serializerType = val.MakeGenericType(objectType.GetGenericArguments());
                             serializer = RegisterSerializer(serializerType)!;
-                            RegisterIndexedSerializer(objectType, _serializerInterfaces.IndexOf(interfaceType), serializer, false);
+                            RegisterIndexedSerializer(objectType, SerializerInterfaces.IndexOf(interfaceType), serializer, false);
                             return true;
                         }
                     }
@@ -299,7 +295,7 @@ public sealed partial class SerializationManager
                             if (arguments.Length != 1)
                                 throw new InvalidGenericParameterCountException();
                             _typeSerializers.GetOrNew(typeInterface).Add(arguments[0], obj);
-                            RegisterIndexedSerializer(arguments[0], _serializerInterfaces.IndexOf(typeInterface), obj, true);
+                            RegisterIndexedSerializer(arguments[0], SerializerInterfaces.IndexOf(typeInterface), obj, true);
                         }
                     }
 
@@ -424,7 +420,7 @@ public sealed partial class SerializationManager
                 Array.Resize(ref _typeSerializersArray, (id + 1) * 2);
             }
 
-            var array = new (object? Regular, object? Generic)[_serializerInterfaces.Length];
+            var array = new (object? Regular, object? Generic)[SerializerInterfaces.Length];
             _typeSerializersArray[id] = array;
 
             if (regular)

Robust.Shared/Serialization/TypeSerializers/Implementations/ComponentRegistrySerializer.cs

@@ -75,16 +75,15 @@ namespace Robust.Shared.Serialization.TypeSerializers.Implementations
             foreach (var componentName in components.Keys)
             {
                 var registration = factory.GetRegistration(componentName);
-                foreach (var compType in registration.References)
-                {
-                    if (referenceTypes.Contains(compType))
-                    {
-                        throw new InvalidOperationException(
-                            $"Duplicate component reference in prototype: '{compType}'");
-                    }
+                var compType = registration.Idx;
 
-                    referenceTypes.Add(compType);
+                if (referenceTypes.Contains(compType))
+                {
+                    throw new InvalidOperationException(
+                        $"Duplicate component reference in prototype: '{compType}'");
                 }
+
+                referenceTypes.Add(compType);
             }
 
             return components;
@@ -139,16 +138,14 @@ namespace Robust.Shared.Serialization.TypeSerializers.Implementations
             foreach (var componentName in components.Keys)
             {
                 var registration = factory.GetRegistration(componentName);
+                var compType = registration.Idx;
 
-                foreach (var compType in registration.References)
+                if (referenceTypes.Contains(compType))
                 {
-                    if (referenceTypes.Contains(compType))
-                    {
-                        return new ErrorNode(node, "Duplicate ComponentReference.");
-                    }
-
-                    referenceTypes.Add(compType);
+                    return new ErrorNode(node, "Duplicate ComponentReference.");
                 }
+
+                referenceTypes.Add(compType);
             }
 
             return new ValidatedSequenceNode(list);
@@ -202,18 +199,15 @@ namespace Robust.Shared.Serialization.TypeSerializers.Implementations
             {
                 foreach (var (childReg, idx) in newCompRegDict)
                 {
-                    foreach (var x in reg.References)
+                    if (childReg.Idx.Equals(reg.Idx))
                     {
-                        if (childReg.References.Contains(x))
-                        {
-                            newCompReg[idx] = serializationManager.PushCompositionWithGenericNode(
-                                reg.Type,
-                                new[] { parent[mapping] },
-                                newCompReg[idx],
-                                context);
+                        newCompReg[idx] = serializationManager.PushCompositionWithGenericNode(
+                            reg.Type,
+                            new[] { parent[mapping] },
+                            newCompReg[idx],
+                            context);
 
-                            goto found;
-                        }
+                        goto found;
                     }
                 }
 

Robust.Shared/Serialization/TypeSerializers/Implementations/EntProtoIdSerializer.cs

@@ -0,0 +1,42 @@
+using Robust.Shared.IoC;
+using Robust.Shared.Prototypes;
+using Robust.Shared.Serialization.Manager;
+using Robust.Shared.Serialization.Manager.Attributes;
+using Robust.Shared.Serialization.Markdown;
+using Robust.Shared.Serialization.Markdown.Validation;
+using Robust.Shared.Serialization.Markdown.Value;
+using Robust.Shared.Serialization.TypeSerializers.Interfaces;
+using static Robust.Shared.Serialization.Manager.ISerializationManager;
+
+namespace Robust.Shared.Serialization.TypeSerializers.Implementations;
+
+/// <summary>
+///     Serializer used automatically for <see cref="EntProtoId"/> types.
+/// </summary>
+[TypeSerializer]
+public sealed class EntProtoIdSerializer : ITypeSerializer<EntProtoId, ValueDataNode>, ITypeCopyCreator<EntProtoId>
+{
+    public ValidationNode Validate(ISerializationManager serialization, ValueDataNode node, IDependencyCollection dependencies, ISerializationContext? context = null)
+    {
+        var prototypes = dependencies.Resolve<IPrototypeManager>();
+        if (prototypes.HasMapping<EntityPrototype>(node.Value))
+            return new ValidatedValueNode(node);
+
+        return new ErrorNode(node, $"No {nameof(EntityPrototype)} found with id {node.Value}");
+    }
+
+    public EntProtoId Read(ISerializationManager serialization, ValueDataNode node, IDependencyCollection dependencies, SerializationHookContext hookCtx, ISerializationContext? context = null, InstantiationDelegate<EntProtoId>? instanceProvider = null)
+    {
+        return new EntProtoId(node.Value);
+    }
+
+    public DataNode Write(ISerializationManager serialization, EntProtoId value, IDependencyCollection dependencies, bool alwaysWrite = false, ISerializationContext? context = null)
+    {
+        return new ValueDataNode(value.Id);
+    }
+
+    public EntProtoId CreateCopy(ISerializationManager serializationManager, EntProtoId source, IDependencyCollection dependencies, SerializationHookContext hookCtx, ISerializationContext? context = null)
+    {
+        return source;
+    }
+}

Robust.Shared/Serialization/TypeSerializers/Implementations/Generic/ProtoIdSerializer.cs

@@ -0,0 +1,43 @@
+using Robust.Shared.IoC;
+using Robust.Shared.Prototypes;
+using Robust.Shared.Serialization.Manager;
+using Robust.Shared.Serialization.Manager.Attributes;
+using Robust.Shared.Serialization.Markdown;
+using Robust.Shared.Serialization.Markdown.Validation;
+using Robust.Shared.Serialization.Markdown.Value;
+using Robust.Shared.Serialization.TypeSerializers.Interfaces;
+using static Robust.Shared.Serialization.Manager.ISerializationManager;
+
+namespace Robust.Shared.Serialization.TypeSerializers.Implementations.Generic;
+
+/// <summary>
+///     Serializer used automatically for <see cref="ProtoId{T}"/> types.
+/// </summary>
+/// <typeparam name="T">The type of the prototype for which the id is stored.</typeparam>
+[TypeSerializer]
+public sealed class ProtoIdSerializer<T> : ITypeSerializer<ProtoId<T>, ValueDataNode>, ITypeCopyCreator<ProtoId<T>> where T : class, IPrototype
+{
+    public ValidationNode Validate(ISerializationManager serialization, ValueDataNode node, IDependencyCollection dependencies, ISerializationContext? context = null)
+    {
+        var prototypes = dependencies.Resolve<IPrototypeManager>();
+        if (prototypes.HasMapping<T>(node.Value))
+            return new ValidatedValueNode(node);
+
+        return new ErrorNode(node, $"No {typeof(T)} found with id {node.Value}");
+    }
+
+    public ProtoId<T> Read(ISerializationManager serialization, ValueDataNode node, IDependencyCollection dependencies, SerializationHookContext hookCtx, ISerializationContext? context = null, InstantiationDelegate<ProtoId<T>>? instanceProvider = null)
+    {
+        return new ProtoId<T>(node.Value);
+    }
+
+    public DataNode Write(ISerializationManager serialization, ProtoId<T> value, IDependencyCollection dependencies, bool alwaysWrite = false, ISerializationContext? context = null)
+    {
+        return new ValueDataNode(value.Id);
+    }
+
+    public ProtoId<T> CreateCopy(ISerializationManager serializationManager, ProtoId<T> source, IDependencyCollection dependencies, SerializationHookContext hookCtx, ISerializationContext? context = null)
+    {
+        return source;
+    }
+}

Robust.Shared/Toolshed/TypeParsers/Math/AngleTypeParser.cs

@@ -34,7 +34,7 @@ public sealed class AngleTypeParser : TypeParser<Angle>
 
         if (word.EndsWith("deg"))
         {
-            if (!float.TryParse(word[..^3], out var f))
+            if (!float.TryParse(word[..^3], CultureInfo.InvariantCulture, out var f))
             {
                 error = new InvalidAngle(word);
                 result = null;
@@ -47,7 +47,7 @@ public sealed class AngleTypeParser : TypeParser<Angle>
         }
         else
         {
-            if (!float.TryParse(word, out var f))
+            if (!float.TryParse(word, CultureInfo.InvariantCulture, out var f))
             {
                 error = new InvalidAngle(word);
                 result = null;

Robust.Shared/Utility/DebugTools.cs

@@ -1,8 +1,10 @@
 using System;
+using System.Data;
 using System.Diagnostics;
 using System.Diagnostics.CodeAnalysis;
 using System.Runtime.CompilerServices;
 using JetBrains.Annotations;
+using Robust.Shared.GameObjects;
 
 namespace Robust.Shared.Utility
 {
@@ -36,6 +38,67 @@ namespace Robust.Shared.Utility
                 throw new DebugAssertException();
         }
 
+        [Conditional("DEBUG")]
+        [AssertionMethod]
+        public static void AssertEqual(object? objA, object? objB)
+        {
+            if (ReferenceEquals(objA, objB))
+                return;
+
+            if (objA == null || !objA.Equals(objB))
+                throw new DebugAssertException($"Expected: {objB ?? "null"} but was {objA ?? "null"}");
+        }
+
+        [Conditional("DEBUG")]
+        [AssertionMethod]
+        public static void AssertEqual(object? objA, object? objB, string message)
+        {
+            if (ReferenceEquals(objA, objB))
+                return;
+
+            if (objA == null || !objA.Equals(objB))
+                throw new DebugAssertException($"{message}\nExpected: {objB ?? "null"} but was {objA ?? "null"}");
+        }
+
+        [Conditional("DEBUG")]
+        [AssertionMethod]
+        public static void AssertNotEqual(object? objA, object? objB)
+        {
+            if (ReferenceEquals(objA, objB))
+                throw new DebugAssertException($"Expected: not {objB ?? "null"}");
+
+            if (objA == null || !objA.Equals(objB))
+                return;
+
+            throw new DebugAssertException($"Expected: not {objB}");
+        }
+
+        [Conditional("DEBUG")]
+        [AssertionMethod]
+        public static void AssertNotEqual(object? objA, object? objB, string message)
+        {
+            if (ReferenceEquals(objA, objB))
+                throw new DebugAssertException($"{message}\nExpected: not {objB ?? "null"}");
+
+            if (objA == null || !objA.Equals(objB))
+                return;
+
+            throw new DebugAssertException($"{message}\nExpected: not {objB}");
+        }
+
+        [Conditional("DEBUG")]
+        [AssertionMethod]
+        public static void AssertOwner(EntityUid? uid, IComponent component)
+        {
+            if (uid == null)
+                throw new DebugAssertException($"Null entity uid cannot own a component. Component: {component.GetType().Name}");
+
+            // Whenever .owner is removed this will need to be replaced by something.
+            // We need some way to ensure that people don't mix up uids & components when calling methods.
+            if (component.Owner != uid)
+                throw new DebugAssertException($"Entity {uid} is not the owner of the component. Component: {component.GetType().Name}");
+        }
+
         /// <summary>
         ///     An assertion that will <see langword="throw" /> an exception if the
         ///     <paramref name="condition" /> is not true.

Robust.UnitTesting/Server/RobustServerSimulation.cs

@@ -223,13 +223,14 @@ namespace Robust.UnitTesting.Server
             container.RegisterInstance<IConsoleHost>(new Mock<IConsoleHost>().Object); //Console is technically a frontend, we want to run headless
             container.Register<IEntityManager, EntityManager>();
             container.Register<EntityManager, EntityManager>();
-            container.Register<IMapManager, MapManager>();
+            container.Register<IMapManager, NetworkedMapManager>();
+            container.Register<INetworkedMapManager, NetworkedMapManager>();
+            container.Register<IMapManagerInternal, NetworkedMapManager>();
             container.Register<ISerializationManager, SerializationManager>();
             container.Register<IPrototypeManager, ServerPrototypeManager>();
             container.Register<IComponentFactory, ComponentFactory>();
             container.Register<IEntitySystemManager, EntitySystemManager>();
             container.Register<IManifoldManager, CollisionManager>();
-            container.Register<IMapManagerInternal, MapManager>();
             container.Register<INetManager, NetManager>();
             container.Register<IAuthManager, AuthManager>();
             container.Register<ITileDefinitionManager, TileDefinitionManager>();

Robust.UnitTesting/Shared/GameState/ComponentStateTests.cs

@@ -153,6 +153,156 @@ public sealed partial class ComponentStateTests : RobustIntegrationTest
         }
     }
 
+    /// <summary>
+    /// This is a variant of <see cref="UnknownEntityTest"/> that deletes one of the entities before the other entity gets sent.
+    /// </summary>
+    [Test]
+    public async Task UnknownEntityDeleteTest()
+    {
+        // The first chunk of the test just follows UnknownEntityTest
+        var compReg = () => IoCManager.Resolve<IComponentFactory>().RegisterClass<UnknownEntityTestComponent>();
+        var sysReg = () => IoCManager.Resolve<IEntitySystemManager>().LoadExtraSystemType<UnknownEntityTestComponent.UnknownEntityTestComponent_AutoNetworkSystem>();
+        var serverOpts = new ServerIntegrationOptions
+        {
+            Pool = false,
+            BeforeRegisterComponents = compReg,
+            BeforeStart = sysReg,
+        };
+        var clientOpts = new ClientIntegrationOptions
+        {
+            Pool = false,
+            BeforeRegisterComponents = compReg,
+            BeforeStart = sysReg,
+        };
+        var server = StartServer(serverOpts);
+        var client = StartClient(clientOpts);
+
+        await Task.WhenAll(client.WaitIdleAsync(), server.WaitIdleAsync());
+        var netMan = client.ResolveDependency<IClientNetManager>();
+        var xforms = server.System<SharedTransformSystem>();
+
+        Assert.DoesNotThrow(() => client.SetConnectTarget(server));
+        client.Post(() => netMan.ClientConnect(null!, 0, null!));
+        server.Post(() => server.CfgMan.SetCVar(CVars.NetPVS, true));
+
+        // Set up map.
+        EntityUid map = default;
+        await server.WaitPost(() =>
+        {
+            var mapId = server.MapMan.CreateMap();
+            map = server.MapMan.GetMapEntityId(mapId);
+        });
+
+        await RunTicks();
+
+        // Spawn entities
+        var coordsA = new EntityCoordinates(map, default);
+        var coordsB = new EntityCoordinates(map, new Vector2(100, 100));
+        EntityUid player = default;
+        EntityUid cPlayer = default;
+        EntityUid serverEntA = default;
+        EntityUid serverEntB = default;
+        NetEntity serverNetA = default;
+        NetEntity serverNetB = default;
+
+        await server.WaitPost(() =>
+        {
+            // Attach player.
+            player = server.EntMan.Spawn();
+            var session = (IPlayerSession) server.PlayerMan.Sessions.First();
+            server.System<ActorSystem>().Attach(player, session);
+            session.JoinGame();
+
+            // Spawn test entities.
+            serverEntA = server.EntMan.SpawnAttachedTo(null, coordsA);
+            serverEntB = server.EntMan.SpawnAttachedTo(null, coordsB);
+            serverNetA = server.EntMan.GetNetEntity(serverEntA);
+            serverNetB = server.EntMan.GetNetEntity(serverEntB);
+
+            // Setup components
+            var cmp = server.EntMan.EnsureComponent<UnknownEntityTestComponent>(serverEntA);
+            cmp.Other = serverEntB;
+            server.EntMan.Dirty(serverEntA, cmp);
+
+            cmp = server.EntMan.EnsureComponent<UnknownEntityTestComponent>(serverEntB);
+            cmp.Other = serverEntA;
+            server.EntMan.Dirty(serverEntB, cmp);
+        });
+
+        await RunTicks();
+
+        // Check player got properly attached and only knows about the expected entities
+        await client.WaitPost(() =>
+        {
+            cPlayer = client.EntMan.GetEntity(server.EntMan.GetNetEntity(player));
+            Assert.That(client.AttachedEntity, Is.EqualTo(cPlayer));
+            Assert.That(client.EntMan.EntityExists(cPlayer));
+            Assert.That(client.EntMan.EntityExists(client.EntMan.GetEntity(serverNetA)), Is.False);
+            Assert.That(client.EntMan.EntityExists(client.EntMan.GetEntity(serverNetB)), Is.False);
+        });
+
+        // Move the player into PVS range of one of the entities.
+        await server.WaitPost(() => xforms.SetCoordinates(player, coordsB));
+        await RunTicks();
+
+        await client.WaitPost(() =>
+        {
+            var clientEntA = client.EntMan.GetEntity(serverNetA);
+            var clientEntB = client.EntMan.GetEntity(serverNetB);
+            Assert.That(client.EntMan.EntityExists(clientEntB), Is.True);
+            Assert.That(client.EntMan.EntityExists(client.EntMan.GetEntity(serverNetA)), Is.False);
+
+            Assert.That(client.EntMan.TryGetComponent(clientEntB, out UnknownEntityTestComponent? cmp));
+            Assert.That(cmp?.Other, Is.EqualTo(clientEntA));
+        });
+
+        // This is where the test difffers from UnknownEntityTest:
+        // We delete the entity that the player knows about before it receives the entity that it references.
+        await server.WaitPost(() =>
+        {
+            server.EntMan.DeleteEntity(serverEntB);
+            var comp = server.EntMan.GetComponent<UnknownEntityTestComponent>(serverEntA);
+            comp.Other = EntityUid.Invalid;
+            server.EntMan.Dirty(serverEntA, comp);
+        });
+        await RunTicks();
+
+        await client.WaitPost(() =>
+        {
+            var clientEntA = client.EntMan.GetEntity(serverNetA);
+            var clientEntB = client.EntMan.GetEntity(serverNetB);
+            Assert.That(clientEntA, Is.EqualTo(EntityUid.Invalid));
+            Assert.That(clientEntB, Is.EqualTo(EntityUid.Invalid));
+        });
+
+        // Move the player into PVS range of the other entity
+        await server.WaitPost(() => xforms.SetCoordinates(player, coordsA));
+        await RunTicks();
+
+        await client.WaitPost(() =>
+        {
+            var clientEntA = client.EntMan.GetEntity(serverNetA);
+            var clientEntB = client.EntMan.GetEntity(serverNetB);
+            Assert.That(clientEntB, Is.EqualTo(EntityUid.Invalid));
+            Assert.That(client.EntMan.EntityExists(clientEntA), Is.True);
+            Assert.That(client.EntMan.TryGetComponent(clientEntA, out UnknownEntityTestComponent? cmp));
+            Assert.That(cmp?.Other, Is.EqualTo(EntityUid.Invalid));
+        });
+
+        server.Post(() => server.CfgMan.SetCVar(CVars.NetPVS, false));
+
+        // wait for errors.
+        await RunTicks();
+
+        async Task RunTicks()
+        {
+            for (int i = 0; i < 10; i++)
+            {
+                await server!.WaitRunTicks(1);
+                await client!.WaitRunTicks(1);
+            }
+        }
+    }
 }
 
 [RegisterComponent, NetworkedComponent, AutoGenerateComponentState]