Version: 162.2.2

(cherry picked from commit 24d5c26fa6)
(cherry picked from commit 688efac67b634c613539b783a9fb6e679948cd53)

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 +54,79 @@ END TEMPLATE-->
 *None yet*
 
 
+## 162.2.2
+
+
+## 162.2.1
+
+
+## 162.2.0
+
+### New features
+
+* Add support for automatically networking entity lists and sets.
+* Add nullable conversion operators for ProtoIds.
+* Add LocId serializer for validation.
+
+### Bugfixes
+
+* Fix deleting a contact inside of collision events throwing.
+* Localize VV.
+
+### Internal
+
+* Use CollectionsMarshal in GameStateManager.
+
+
+## 162.1.1
+
+### Bugfixes
+
+* Fixes "NoSpawn" entities appearing in the spawn menu.
+
+
+## 162.1.0
+
+### New features
+
+* Mark ProtoId as NetSerializable.
+
+### Bugfixes
+
+* Temporarily revert NetForceAckThreshold change as it can lead to client stalling.
+* Fix eye visibility layers not updating on children when a parent changes.
+
+### Internal
+
+* Use CollectionsMarshal in RobustTree and AddComponentInternal.
+
+
+## 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

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

Resources/Locale/en-US/view-variables.ftl

@@ -1,5 +1,6 @@
 ## ViewVariablesInstanceEntity
 
+view-variables = View Variables
 view-variable-instance-entity-server-components-add-component-button-placeholder = Add Component
 view-variable-instance-entity-client-variables-tab-title = Client Variables
 view-variable-instance-entity-client-components-tab-title = Client Components
@@ -8,4 +9,4 @@ view-variable-instance-entity-server-components-tab-title = Server Components
 view-variable-instance-entity-client-components-search-bar-placeholder = Search
 view-variable-instance-entity-server-components-search-bar-placeholder = Search
 view-variable-instance-entity-add-window-server-components = Add Component [S]
-view-variable-instance-entity-add-window-client-components = Add Component [C]
+view-variable-instance-entity-add-window-client-components = Add Component [C]

Robust.Client/GameStates/ClientGameStateManager.cs

@@ -4,6 +4,7 @@ using System;
 using System.Collections.Generic;
 using System.Diagnostics.CodeAnalysis;
 using System.Linq;
+using System.Runtime.InteropServices;
 using JetBrains.Annotations;
 using Robust.Client.GameObjects;
 using Robust.Client.Input;
@@ -759,25 +760,29 @@ namespace Robust.Client.GameStates
                     if (es.EntityLastModified != nextState.ToSequence)
                         continue;
 
-                    if (_toApply.TryGetValue(uid.Value, out var state))
-                        _toApply[uid.Value] = (es.NetEntity, meta, state.EnteringPvs, state.LastApplied, state.curState, es);
+                    ref var state = ref CollectionsMarshal.GetValueRefOrAddDefault(_toApply, uid.Value, out var exists);
+
+                    if (exists)
+                        state = (es.NetEntity, meta, state.EnteringPvs, state.LastApplied, state.curState, es);
                     else
-                        _toApply[uid.Value] = (es.NetEntity, meta, false, GameTick.Zero, null, es);
+                        state = (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;
-
                 // 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);
+                // State already being re-applied so don't bulldoze it.
+                ref var state = ref CollectionsMarshal.GetValueRefOrAddDefault(_toApply, uid, out var exists);
+
+                if (exists)
+                    continue;
+
+                state = (meta.NetEntity, meta, false, GameTick.Zero, null, null);
             }
 
             var queuedBroadphaseUpdates = new List<(EntityUid, TransformComponent)>(enteringPvs);
@@ -1198,10 +1203,13 @@ namespace Robust.Client.GameStates
                         continue;
                     }
 
-                    if (_compStateWork.TryGetValue(compState.NetID, out var state))
-                        _compStateWork[compState.NetID] = (comp, state.curState, compState.State);
+                    ref var state =
+                        ref CollectionsMarshal.GetValueRefOrAddDefault(_compStateWork, compState.NetID, out var exists);
+
+                    if (exists)
+                        state = (comp, state.curState, compState.State);
                     else
-                        _compStateWork[compState.NetID] = (comp, null, compState.State);
+                        state = (comp, null, compState.State);
                 }
             }
 
@@ -1218,14 +1226,19 @@ namespace Robust.Client.GameStates
                     if (netId == null)
                         continue;
 
-                    if (_compStateWork.ContainsKey(netId.Value) ||
-                        !meta.NetComponents.TryGetValue(netId.Value, out var comp) ||
+                    if (!meta.NetComponents.TryGetValue(netId.Value, out var comp) ||
                         !lastState.TryGetValue(netId.Value, out var lastCompState))
                     {
                         continue;
                     }
 
-                    _compStateWork[netId.Value] = (comp, lastCompState, null);
+                    ref var compState =
+                        ref CollectionsMarshal.GetValueRefOrAddDefault(_compStateWork, netId.Value, out var exists);
+
+                    if (exists)
+                        continue;
+
+                    compState = (comp, lastCompState, null);
                 }
             }
 

Robust.Client/GameStates/GameStateProcessor.cs

@@ -1,5 +1,6 @@
 using System.Collections.Generic;
 using System.Diagnostics.CodeAnalysis;
+using System.Runtime.InteropServices;
 using Robust.Client.Timing;
 using Robust.Shared.GameObjects;
 using Robust.Shared.GameStates;
@@ -361,9 +362,11 @@ namespace Robust.Client.GameStates
 
                 foreach (var (netId, implicitCompState) in implicitEntState)
                 {
-                    if (!fullRep.TryGetValue(netId, out var serverState))
+                    ref var serverState = ref CollectionsMarshal.GetValueRefOrAddDefault(fullRep, netId, out var exists);
+
+                    if (!exists)
                     {
-                        fullRep.Add(netId, implicitCompState);
+                        serverState = implicitCompState;
                         continue;
                     }
 
@@ -379,7 +382,7 @@ namespace Robust.Client.GameStates
                     }
 
                     serverDelta.ApplyToFullState(implicitCompState);
-                    fullRep[netId] = implicitCompState;
+                    serverState = implicitCompState;
                     DebugTools.Assert(implicitCompState is IComponentDeltaState d && d.FullState);
                 }
             }

Robust.Client/Robust.Client.csproj

@@ -17,7 +17,7 @@
     <PackageReference Include="SQLitePCLRaw.bundle_e_sqlite3" Version="2.1.2" Condition="'$(UseSystemSqlite)' != 'True'" PrivateAssets="compile" />
     <PackageReference Include="SpaceWizards.NFluidsynth" Version="0.1.1" PrivateAssets="compile" />
     <PackageReference Include="NVorbis" Version="0.10.1" PrivateAssets="compile" />
-    <PackageReference Include="SixLabors.ImageSharp" Version="2.1.3" />
+    <PackageReference Include="SixLabors.ImageSharp" Version="2.1.7" />
     <PackageReference Include="OpenToolkit.Graphics" Version="4.0.0-pre9.1" PrivateAssets="compile" />
     <PackageReference Include="OpenTK.OpenAL" Version="4.7.5" PrivateAssets="compile" />
     <PackageReference Include="SpaceWizards.SharpFont" Version="1.0.1" PrivateAssets="compile" />

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/Controls/LineEdit.cs

@@ -98,6 +98,11 @@ namespace Robust.Client.UserInterface.Controls
                 OnTextChanged?.Invoke(new LineEditEventArgs(this, _text));
         }
 
+        public void ForceSubmitText()
+        {
+            OnTextEntered?.Invoke(new LineEditEventArgs(this, _text));
+        }
+
         /// <summary>
         ///     The text
         /// </summary>
@@ -607,7 +612,7 @@ namespace Robust.Client.UserInterface.Controls
                 {
                     if (Editable)
                     {
-                        OnTextEntered?.Invoke(new LineEditEventArgs(this, _text));
+                        ForceSubmitText();
                     }
 
                     args.Handle();

Robust.Client/UserInterface/Controls/ScrollContainer.cs

@@ -50,13 +50,13 @@ namespace Robust.Client.UserInterface.Controls
             Action<Range> ev = _scrollValueChanged;
             _hScrollBar = new HScrollBar
             {
-                Visible = false,
+                Visible = _hScrollEnabled,
                 VerticalAlignment = VAlignment.Bottom,
                 HorizontalAlignment = HAlignment.Stretch
             };
             _vScrollBar = new VScrollBar
             {
-                Visible = false,
+                Visible = _vScrollEnabled,
                 VerticalAlignment = VAlignment.Stretch,
                 HorizontalAlignment = HAlignment.Right
             };

Robust.Client/ViewVariables/ClientViewVariablesManager.cs

@@ -10,6 +10,7 @@ using Robust.Client.ViewVariables.Editors;
 using Robust.Client.ViewVariables.Instances;
 using Robust.Shared.GameObjects;
 using Robust.Shared.IoC;
+using Robust.Shared.Localization;
 using Robust.Shared.Map;
 using Robust.Shared.Maths;
 using Robust.Shared.Network;
@@ -232,7 +233,7 @@ namespace Robust.Client.ViewVariables
                 instance = new ViewVariablesInstanceObject(this, _robustSerializer);
             }
 
-            var window = new DefaultWindow {Title = "View Variables"};
+            var window = new DefaultWindow {Title = Loc.GetString("view-variables")};
             instance.Initialize(window, obj);
             window.OnClose += () => _closeInstance(instance, false);
             _windows.Add(instance, window);
@@ -250,7 +251,7 @@ namespace Robust.Client.ViewVariables
         {
             var window = new DefaultWindow
             {
-                Title = "View Variables",
+                Title = Loc.GetString("view-variables"),
                 SetSize = _defaultWindowSize
             };
             var loadingLabel = new Label {Text = "Retrieving remote object data from server..."};

Robust.Server/GameObjects/EntitySystems/ServerMetaDataSystem.cs

@@ -75,13 +75,4 @@ public sealed class ServerMetaDataSystem : MetaDataSystem
                 Dirty(uid, comp);
         }
     }
-
-    public override void SetVisibilityMask(EntityUid uid, int value, MetaDataComponent? meta = null)
-    {
-        if (!Resolve(uid, ref meta) || meta.VisibilityMask == value)
-            return;
-
-        base.SetVisibilityMask(uid, value, meta);
-        _pvsSystem.MarkDirty(uid);
-    }
 }

Robust.Server/GameObjects/EntitySystems/VisibilitySystem.cs

@@ -1,4 +1,5 @@
 using System;
+using Robust.Server.GameStates;
 using Robust.Shared.GameObjects;
 using Robust.Shared.IoC;
 
@@ -6,11 +7,18 @@ namespace Robust.Server.GameObjects
 {
     public sealed class VisibilitySystem : EntitySystem
     {
-        [Dependency] private readonly MetaDataSystem _metaSys = default!;
+        [Dependency] private readonly PvsSystem _pvs = default!;
+
+        private EntityQuery<TransformComponent> _xformQuery;
+        private EntityQuery<MetaDataComponent> _metaQuery;
+        private EntityQuery<VisibilityComponent> _visiblityQuery;
 
         public override void Initialize()
         {
             base.Initialize();
+            _xformQuery = GetEntityQuery<TransformComponent>();
+            _metaQuery = GetEntityQuery<MetaDataComponent>();
+            _visiblityQuery = GetEntityQuery<VisibilityComponent>();
             SubscribeLocalEvent<EntParentChangedMessage>(OnParentChange);
             EntityManager.EntityInitialized += OnEntityInit;
         }
@@ -82,27 +90,58 @@ namespace Robust.Server.GameObjects
             RefreshVisibility(uid);
         }
 
-        public void RefreshVisibility(EntityUid uid, MetaDataComponent? metaDataComponent = null, VisibilityComponent? visibilityComponent = null)
+        public void RefreshVisibility(EntityUid uid,
+            VisibilityComponent? visibilityComponent = null,
+            MetaDataComponent? meta = null)
         {
-            if (Resolve(uid, ref metaDataComponent, false))
-                _metaSys.SetVisibilityMask(uid, GetVisibilityMask(uid, visibilityComponent), metaDataComponent);
+            if (!_metaQuery.Resolve(uid, ref meta, false))
+                return;
+
+            // Iterate up through parents and calculate the cumulative visibility mask.
+            var mask = GetParentVisibilityMask(uid, visibilityComponent);
+
+            // Iterate down through children and propagate mask changes.
+            RecursivelyApplyVisibility(uid, mask, meta);
+        }
+
+        private void RecursivelyApplyVisibility(EntityUid uid, int mask, MetaDataComponent meta)
+        {
+            if (meta.VisibilityMask == mask)
+                return;
+
+            var xform = _xformQuery.GetComponent(uid);
+            meta.VisibilityMask = mask;
+            _pvs.MarkDirty(uid, xform);
+
+            foreach (var child in xform.ChildEntities)
+            {
+                if (!_metaQuery.TryGetComponent(child, out var childMeta))
+                    continue;
+
+                var childMask = mask;
+
+                if (_visiblityQuery.TryGetComponent(child, out VisibilityComponent? hildVis))
+                    childMask |= hildVis.Layer;
+
+                RecursivelyApplyVisibility(child, childMask, childMeta);
+            }
         }
 
         [Obsolete("Use overload that takes an EntityUid instead")]
         public void RefreshVisibility(VisibilityComponent visibilityComponent)
         {
-            RefreshVisibility(visibilityComponent.Owner, null, visibilityComponent);
+            RefreshVisibility(visibilityComponent.Owner, visibilityComponent);
         }
 
-        private int GetVisibilityMask(EntityUid uid, VisibilityComponent? visibilityComponent = null, TransformComponent? xform = null)
+        private int GetParentVisibilityMask(EntityUid uid, VisibilityComponent? visibilityComponent = null)
         {
             int visMask = 1; // apparently some content expects everything to have the first bit/flag set to true.
-            if (Resolve(uid, ref visibilityComponent, false))
+            if (_visiblityQuery.Resolve(uid, ref visibilityComponent, false))
                 visMask |= visibilityComponent.Layer;
 
             // Include parent vis masks
-            if (Resolve(uid, ref xform) && xform.ParentUid.IsValid())
-                visMask |= GetVisibilityMask(xform.ParentUid);
+            if (_xformQuery.TryGetComponent(uid, out var xform) && xform.ParentUid.IsValid())
+                visMask |= GetParentVisibilityMask(xform.ParentUid);
 
             return visMask;
         }

Robust.Server/GameStates/PvsSystem.Dirty.cs

@@ -92,9 +92,9 @@ namespace Robust.Server.GameStates
         /// <summary>
         ///     Marks an entity's current chunk as dirty.
         /// </summary>
-        internal void MarkDirty(EntityUid uid)
+        internal void MarkDirty(EntityUid uid, TransformComponent xform)
         {
-            var coordinates = _transform.GetMoverCoordinates(uid);
+            var coordinates = _transform.GetMoverCoordinates(uid, xform);
             _entityPvsCollection.MarkDirty(_entityPvsCollection.GetChunkIndex(coordinates));
         }
     }

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!;
@@ -227,6 +228,7 @@ 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:
@@ -648,16 +650,16 @@ internal sealed partial class PvsSystem : EntitySystem
         }
     }
 
-    private bool AddToChunkSetRecursively(in EntityUid uid, in NetEntity netEntity, MetaDataComponent mComp,
+    private void AddToChunkSetRecursively(in EntityUid uid, in NetEntity netEntity, MetaDataComponent mComp,
         int visMask, RobustTree<NetEntity> tree, Dictionary<NetEntity, MetaDataComponent> set)
     {
-        if (set.ContainsKey(netEntity))
-            return true;
-
-        // 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 the eye is missing ANY layer that this entity is on, or any layer that any of its parents belongs to, then
+        // it is considered invisible.
         if ((visMask & mComp.VisibilityMask) != mComp.VisibilityMask)
-            return false;
+            return;
+
+        if (!set.TryAdd(netEntity, mComp))
+            return; // already sending
 
         var xform = _xformQuery.GetComponent(uid);
 
@@ -667,8 +669,7 @@ internal sealed partial class PvsSystem : EntitySystem
         {
             DebugTools.Assert(_mapManager.IsGrid(uid) || _mapManager.IsMap(uid));
             tree.Set(netEntity);
-            set.Add(netEntity, mComp);
-            return true;
+            return;
         }
 
         DebugTools.Assert(!_mapManager.IsGrid(uid) && !_mapManager.IsMap(uid));
@@ -677,15 +678,12 @@ internal sealed partial class PvsSystem : EntitySystem
         var parentMeta = _metaQuery.GetComponent(parent);
         var parentNetEntity = parentMeta.NetEntity;
 
-        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
-        }
+        // Child should have all o the same flags as the parent.
+        DebugTools.Assert((parentMeta.VisibilityMask & mComp.VisibilityMask) == parentMeta.VisibilityMask);
 
-        //i want it to crash here if it gets added double bc that shouldnt happen and will add alot of unneeded cycles
+        // Add our parent.
+        AddToChunkSetRecursively(in parent, in parentNetEntity, parentMeta, visMask, tree, set);
         tree.Set(netEntity, parentNetEntity);
-        set.Add(netEntity, mComp);
-        return true;
     }
 
     internal (List<EntityState>? updates, List<NetEntity>? deletions, List<NetEntity>? leftPvs, GameTick fromTick)
@@ -900,15 +898,22 @@ 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;
+                }
 
-                AddToSendSet(in currentNodeIndex, metaDataCache[currentNodeIndex], toSend, fromTick, in entered, ref entStateCount);
+                AddToSendSet(in currentNodeIndex, metaDataCache[currentNodeIndex], ref value, toSend, fromTick, in entered, ref entStateCount);
             }
 
             var node = tree[currentNodeIndex];
@@ -957,14 +962,15 @@ internal sealed partial class PvsSystem : EntitySystem
         // 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, metadata, toSend, fromTick, in entered, ref entStateCount);
+            AddToSendSet(in netEntity, metadata, ref value, toSend, fromTick, in entered, ref entStateCount);
         }
 
         if (addChildren)
@@ -996,12 +1002,13 @@ internal sealed partial class PvsSystem : EntitySystem
             var metadata = _metaQuery.GetComponent(child);
             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,
@@ -1044,10 +1051,13 @@ 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;
@@ -1055,7 +1065,7 @@ internal sealed partial class PvsSystem : EntitySystem
 
         if (entered)
         {
-            toSend.Add(netEntity, PvsEntityVisibility.Entered);
+            vis = PvsEntityVisibility.Entered;
             entStateCount++;
             return;
         }
@@ -1063,12 +1073,12 @@ 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++;
     }
 

Robust.Server/GameStates/RobustTree.cs

@@ -1,6 +1,6 @@
 using System;
 using System.Collections.Generic;
-using System.Diagnostics.CodeAnalysis;
+using System.Runtime.InteropServices;
 using Microsoft.Extensions.ObjectPool;
 using Robust.Shared.Utility;
 
@@ -89,56 +89,76 @@ public sealed class RobustTree<T> where T : notnull
         throw new InvalidOperationException("Node neither had a parent nor was a RootNode.");
     }
 
-    public TreeNode Set(T rootNode)
+    public void Set(T rootNode)
     {
-        //root node, for now
-        if (_nodeIndex.TryGetValue(rootNode, out var node))
+        ref var node = ref CollectionsMarshal.GetValueRefOrAddDefault(_nodeIndex, rootNode, out var exists);
+
+        if (exists)
         {
             if(!RootNodes.Contains(rootNode))
                 throw new InvalidOperationException("Node already exists as non-root node.");
-            return node;
+            return;
         }
 
         node = new TreeNode(rootNode);
-        _nodeIndex.Add(rootNode, node);
-        RootNodes.Add(rootNode);
-        return node;
+        if(!RootNodes.Add(rootNode))
+            throw new InvalidOperationException("Non-existent node was already a root node?");
     }
 
-    public TreeNode Set(T child, T parent)
+    public void Set(T child, T parent)
     {
-        if (!_nodeIndex.TryGetValue(parent, out var parentNode))
-            parentNode = Set(parent);
-
-        if (parentNode.Children == null)
+        // Code block for where parentNode is a valid ref
         {
-            _nodeIndex[parent] = parentNode = parentNode.WithChildren(_pool.Get());
-        }
+            ref var parentNode = ref CollectionsMarshal.GetValueRefOrAddDefault(_nodeIndex, parent, out var parentExists);
 
-        if (_nodeIndex.TryGetValue(child, out var existingNode))
-        {
-            if (RootNodes.Contains(child))
+            // If parent does not exist we make it a new root node.
+            if (!parentExists)
             {
-                parentNode.Children!.Add(existingNode.Value);
-                RootNodes.Remove(child);
-                _parents.Add(child, parent);
-                return existingNode;
+                parentNode = new TreeNode(parent);
+                if (!RootNodes.Add(parent))
+                {
+                    _nodeIndex.Remove(parent);
+                    throw new InvalidOperationException("Non-existent node was already a root node?");
+                }
             }
 
-            if (!_parents.TryGetValue(child, out var previousParent) || _nodeIndex.TryGetValue(previousParent, out var previousParentNode))
-                throw new InvalidOperationException("Could not find old parent for non-root node.");
-
-            previousParentNode.Children?.Remove(existingNode.Value);
-            parentNode.Children!.Add(existingNode.Value);
-            _parents[child] = parent;
-            return existingNode;
+            var children = parentNode.Children;
+            if (children == null)
+            {
+                children = _pool.Get();
+                parentNode = parentNode.WithChildren(children);
+                DebugTools.AssertNotNull(_nodeIndex[parent].Children);
+            }
+            children.Add(child);
         }
 
-        existingNode = new TreeNode(child);
-        _nodeIndex.Add(child, existingNode);
-        parentNode.Children!.Add(existingNode.Value);
-        _parents.Add(child, parent);
-        return existingNode;
+        // No longer safe to access parentNode ref after this.
+
+        ref var node = ref CollectionsMarshal.GetValueRefOrAddDefault(_nodeIndex, child, out var childExists);
+        if (!childExists)
+        {
+            // This is the path that PVS should take 99% of the time.
+            node = new TreeNode(child);
+            _parents.Add(child, parent);
+            return;
+        }
+
+        if (RootNodes.Remove(child))
+        {
+            DebugTools.Assert(!_parents.ContainsKey(child));
+            _parents.Add(child, parent);
+            return;
+        }
+
+        ref var parentEntry = ref CollectionsMarshal.GetValueRefOrAddDefault(_parents, child, out var previousParentExists);
+        if (!previousParentExists || !_nodeIndex.TryGetValue(parentEntry!, out var previousParentNode))
+        {
+            parentEntry = parent;
+            throw new InvalidOperationException("Could not find old parent for non-root node.");
+        }
+
+        previousParentNode.Children?.Remove(child);
+        parentEntry = parent;
     }
 
     public readonly struct TreeNode : IEquatable<TreeNode>

Robust.Server/GameStates/ServerGameStateManager.cs

@@ -99,10 +99,10 @@ namespace Robust.Server.GameStates
                 .Select(x => $"{x.Name} ({_entityManager.ToPrettyString(x.AttachedEntity)})");
 
             shell.WriteLine($@"Current tick: {_gameTiming.CurTick}
-Last Acked tick: {_lastOldestAck}
-Deletion history size: {_pvs.EntityPVSCollection.GetDeletedIndices(_lastOldestAck)?.Count ?? 0}
-Actual last acked tick: {ack}
-Last ack players: {string.Join(", ", players)}
+Stored oldest acked tick: {_lastOldestAck}
+Deletion history size: {_pvs.EntityPVSCollection.GetDeletedIndices(GameTick.First)?.Count ?? 0}
+Actual oldest: {ack}
+Oldest acked clients: {string.Join(", ", players)}
 ");
         }
 
@@ -168,15 +168,6 @@ Last ack players: {string.Join(", ", players)}
         /// <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
@@ -216,14 +207,21 @@ Last ack players: {string.Join(", ", players)}
                 _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)

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.Shared.CompNetworkGenerator/ComponentNetworkGenerator.cs

@@ -16,12 +16,15 @@ namespace Robust.Shared.CompNetworkGenerator
         private const string MemberAttributeName = "Robust.Shared.Analyzers.AutoNetworkedFieldAttribute";
         private const string GlobalEntityUidName = "global::Robust.Shared.GameObjects.EntityUid";
         private const string GlobalNullableEntityUidName = "global::Robust.Shared.GameObjects.EntityUid?";
-        private const string GlobalEntityCoordinatesName = "global::Robust.Shared.Map.EntityCoordinates?";
-        private const string GlobalNullableEntityCoordinatesName = "global::Robust.Shared.Map.EntityCoordinates";
+        private const string GlobalEntityCoordinatesName = "global::Robust.Shared.Map.EntityCoordinates";
+        private const string GlobalNullableEntityCoordinatesName = "global::Robust.Shared.Map.EntityCoordinates?";
+        private const string GlobalEntityUidSetName = "global::System.Collections.Generic.HashSet<global::Robust.Shared.GameObjects.EntityUid>";
+        private const string GlobalNetEntityUidSetName = "global::System.Collections.Generic.HashSet<global::Robust.Shared.GameObjects.NetEntity>";
+        private const string GlobalEntityUidListName = "global::System.Collections.Generic.List<global::Robust.Shared.GameObjects.EntityUid>";
+        private const string GlobalNetEntityUidListName = "global::System.Collections.Generic.List<global::Robust.Shared.GameObjects.NetEntity>";
 
         private static string GenerateSource(in GeneratorExecutionContext context, INamedTypeSymbol classSymbol, CSharpCompilation comp, bool raiseAfterAutoHandle)
         {
-            // Debugger.Launch();
             var nameSpace = classSymbol.ContainingNamespace.ToDisplayString();
             var componentName = classSymbol.Name;
             var stateName = $"{componentName}_AutoState";
@@ -172,6 +175,26 @@ namespace Robust.Shared.CompNetworkGenerator
             component.{name} = state.{name};");
                         }
 
+                        break;
+                    case GlobalEntityUidSetName:
+                        stateFields.Append($@"
+        public {GlobalNetEntityUidSetName} {name} = default!;");
+
+                        getStateInit.Append($@"
+                {name} = GetNetEntitySet(component.{name}),");
+                        handleStateSetters.Append($@"
+            component.{name} = EnsureEntitySet<{componentName}>(state.{name}, uid);");
+
+                        break;
+                    case GlobalEntityUidListName:
+                        stateFields.Append($@"
+        public {GlobalNetEntityUidListName} {name} = default!;");
+
+                        getStateInit.Append($@"
+                {name} = GetNetEntityList(component.{name}),");
+                        handleStateSetters.Append($@"
+            component.{name} = EnsureEntityList<{componentName}>(state.{name}, uid);");
+
                         break;
                 }
             }

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/Containers/BaseContainer.cs

@@ -13,6 +13,7 @@ using System;
 using System.Collections.Generic;
 using System.Linq;
 using System.Numerics;
+using Robust.Shared.Log;
 using Robust.Shared.Serialization;
 
 namespace Robust.Shared.Containers
@@ -111,6 +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>();
@@ -121,6 +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/Components/MetaDataComponent.cs

@@ -189,15 +189,8 @@ namespace Robust.Shared.GameObjects
         /// <remarks>
         ///     Every entity will always have the first bit set to true.
         /// </remarks>
-        [Access(typeof(MetaDataSystem))]
-        public int VisibilityMask = 1;
-
-        [UsedImplicitly, ViewVariables(VVAccess.ReadWrite)]
-        private int VVVisibilityMask
-        {
-            get => VisibilityMask;
-            set => IoCManager.Resolve<IEntitySystemManager>().GetEntitySystem<MetaDataSystem>().SetVisibilityMask(Owner, value, this);
-        }
+        [ViewVariables] // TODO ACCESS RRestrict writing to server-side visibility system
+        public int VisibilityMask { get; internal set; }= 1;
 
         [ViewVariables]
         public bool EntityPaused => PauseTime != null;

Robust.Shared/GameObjects/EntityManager.Components.cs

@@ -4,6 +4,7 @@ using System.Diagnostics;
 using System.Diagnostics.CodeAnalysis;
 using System.Linq;
 using System.Runtime.CompilerServices;
+using System.Runtime.InteropServices;
 using JetBrains.Annotations;
 using Robust.Shared.GameStates;
 using Robust.Shared.Log;
@@ -285,17 +286,29 @@ namespace Robust.Shared.GameObjects
             var dict = _entTraitArray[type.Value];
             DebugTools.Assert(dict != null);
 
-            if (dict.TryGetValue(uid, out var duplicate))
+            // Code block to restrict access to ref comp.
             {
-                if (!overwrite && !duplicate.Deleted)
-                    throw new InvalidOperationException(
-                        $"Component reference type {component.GetType().Name} already occupied by {duplicate}");
+                ref var comp = ref CollectionsMarshal.GetValueRefOrAddDefault(dict, uid, out var exists);
+                if (exists)
+                {
+                    if (!overwrite && !comp!.Deleted)
+                    {
+                        throw new InvalidOperationException(
+                            $"Component reference type {reg.Name} already occupied by {comp}");
+                    }
 
-                RemoveComponentImmediate(duplicate, uid, false, metadata);
+                    // This will invalidate the comp ref as it removes the key from the dictionary.
+                    // This is inefficient, but component overriding rarely ever happens.
+                    RemoveComponentImmediate(comp!, uid, false, metadata);
+                    dict.Add(uid, component);
+                }
+                else
+                {
+                    comp = component;
+                }
             }
 
             // actually ADD the component
-            dict.Add(uid, component);
             _entCompIndex.Add(uid, component);
 
             // add the component to the netId grid

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

@@ -39,8 +39,8 @@ namespace Robust.Shared.GameObjects
         // 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
 
@@ -241,7 +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()
@@ -324,7 +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;
         }
 
@@ -332,7 +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)
             {
@@ -371,18 +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;
@@ -453,7 +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
@@ -485,7 +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).
@@ -567,7 +557,7 @@ namespace Robust.Shared.GameObjects
 
         public bool EntityExists(EntityUid uid)
         {
-            return _entTraitArray[CompIdx.ArrayIndex<MetaDataComponent>()].ContainsKey(uid);
+            return MetaQuery.HasComponentInternal(uid);
         }
 
         public bool EntityExists(EntityUid? uid)
@@ -586,12 +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>
@@ -716,7 +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)

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;
@@ -458,6 +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)
@@ -471,6 +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)
@@ -492,7 +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>
@@ -502,7 +540,7 @@ 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)]
@@ -511,6 +549,13 @@ public partial class EntitySystem
         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
 
     #region Component Has

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/Systems/MetaDataSystem.cs

@@ -148,12 +148,6 @@ public abstract class MetaDataSystem : EntitySystem
 
         component.Flags &= ~ev.ToRemove;
     }
-
-    public virtual void SetVisibilityMask(EntityUid uid, int value, MetaDataComponent? meta = null)
-    {
-        if (Resolve(uid, ref meta))
-            meta.VisibilityMask = value;
-    }
 }
 
 /// <summary>

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/Localization/ILocalizationManager.cs

@@ -2,7 +2,6 @@ using System;
 using System.Diagnostics.CodeAnalysis;
 using System.Globalization;
 using JetBrains.Annotations;
-using Robust.Shared.ContentPack;
 using Robust.Shared.Serialization;
 
 namespace Robust.Shared.Localization
@@ -23,7 +22,7 @@ namespace Robust.Shared.Localization
     public interface ILocalizationManager
     {
         /// <summary>
-        ///     Gets a language approrpiate string represented by the supplied messageId.
+        ///     Gets a language appropriate string represented by the supplied messageId.
         /// </summary>
         /// <param name="messageId">Unique Identifier for a translated message.</param>
         /// <returns>
@@ -31,6 +30,13 @@ namespace Robust.Shared.Localization
         /// </returns>
         string GetString(string messageId);
 
+        /// <summary>
+        ///     Checks if the specified id has been registered, without checking its arguments.
+        /// </summary>
+        /// <param name="messageId">Unique Identifier for a translated message.</param>
+        /// <returns>true if it exists, even if it requires any parameters to be passed.</returns>
+        bool HasString(string messageId);
+
         /// <summary>
         ///     Try- version of <see cref="GetString(string)"/>
         /// </summary>
@@ -46,7 +52,7 @@ namespace Robust.Shared.Localization
         string GetString(string messageId, params (string, object)[] args);
 
         /// <summary>
-        ///     Try- version of <see cref="GetString(string, ValueTuple{string, object}[])"/>
+        ///     Try- version of <see cref="GetString(string, (string, object)[])"/>
         /// </summary>
         /// <remarks>
         ///     Does not log a warning if the message does not exist.

Robust.Shared/Localization/LocId.cs

@@ -0,0 +1,41 @@
+using System;
+using Robust.Shared.Serialization;
+using Robust.Shared.Serialization.TypeSerializers.Implementations;
+
+namespace Robust.Shared.Localization;
+
+/// <summary>
+///     Wrapper type for a localization string id.
+/// </summary>
+/// <param name="Id">The id of the localization string.</param>
+/// <remarks>
+///     This will be automatically validated by <see cref="LocIdSerializer"/> if used in data fields.</remarks>
+/// <seealso cref="Loc.GetString(string)"/>
+[Serializable, NetSerializable]
+public readonly record struct LocId(string Id) : IEquatable<string>, IComparable<LocId>
+{
+    public static implicit operator string(LocId locId)
+    {
+        return locId.Id;
+    }
+
+    public static implicit operator LocId(string id)
+    {
+        return new LocId(id);
+    }
+
+    public static implicit operator LocId?(string? id)
+    {
+        return id == null ? default(LocId?) : new LocId(id);
+    }
+
+    public bool Equals(string? other)
+    {
+        return Id == other;
+    }
+
+    public int CompareTo(LocId other)
+    {
+        return string.Compare(Id, other.Id, StringComparison.Ordinal);
+    }
+}

Robust.Shared/Localization/LocalizationManager.cs

@@ -4,7 +4,6 @@ using System.Diagnostics.CodeAnalysis;
 using System.Globalization;
 using System.IO;
 using System.Linq;
-using JetBrains.Annotations;
 using Linguini.Bundle;
 using Linguini.Bundle.Builder;
 using Linguini.Bundle.Errors;
@@ -55,7 +54,6 @@ namespace Robust.Shared.Localization
             return msg;
         }
 
-
         public string GetString(string messageId, params (string, object)[] args0)
         {
             if (_defaultCulture == null)
@@ -70,6 +68,11 @@ namespace Robust.Shared.Localization
             return msg;
         }
 
+        public bool HasString(string messageId)
+        {
+            return HasMessage(messageId, out _);
+        }
+
         public bool TryGetString(string messageId, [NotNullWhen(true)] out string? value)
         {
             return TryGetString(messageId, out value, null);

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/Contacts/Contact.cs

@@ -365,5 +365,7 @@ namespace Robust.Shared.Physics.Dynamics.Contacts
         /// Is this a special contact for grid-grid collisions
         /// </summary>
         Grid = 1 << 2,
+
+        Deleting = 1 << 3,
     }
 }

Robust.Shared/Physics/Systems/FixtureSystem.cs

@@ -189,8 +189,6 @@ namespace Robust.Shared.Physics.Systems
                 _lookup.DestroyProxies(uid, fixtureId, fixture, xform, broadphase, physicsMap);
             }
 
-
-
             if (updates)
             {
                 var resetMass = fixture.Density > 0f;

Robust.Shared/Physics/Systems/SharedPhysicsSystem.Contacts.cs

@@ -312,12 +312,17 @@ public abstract partial class SharedPhysicsSystem
 
     public void DestroyContact(Contact contact)
     {
+        // Don't recursive update or we're in for a bad time.
+        if ((contact.Flags & ContactFlags.Deleting) != 0x0)
+            return;
+
         Fixture fixtureA = contact.FixtureA!;
         Fixture fixtureB = contact.FixtureB!;
         var bodyA = contact.BodyA!;
         var bodyB = contact.BodyB!;
         var aUid = contact.EntityA;
         var bUid = contact.EntityB;
+        contact.Flags |= ContactFlags.Deleting;
 
         if (contact.IsTouching)
         {

Robust.Shared/Prototypes/EntProtoId.cs

@@ -13,7 +13,7 @@ namespace Robust.Shared.Prototypes;
 /// </remarks>
 /// <remarks><seealso cref="ProtoId{T}"/> for a wrapper of other prototype kinds.</remarks>
 [Serializable, NetSerializable]
-public readonly record struct EntProtoId(string Id)
+public readonly record struct EntProtoId(string Id) : IEquatable<string>, IComparable<EntProtoId>
 {
     public static implicit operator string(EntProtoId protoId)
     {
@@ -24,4 +24,19 @@ public readonly record struct EntProtoId(string Id)
     {
         return new EntProtoId(id);
     }
+
+    public static implicit operator EntProtoId?(string? id)
+    {
+        return id == null ? default(EntProtoId?) : new EntProtoId(id);
+    }
+
+    public bool Equals(string? other)
+    {
+        return Id == other;
+    }
+
+    public int CompareTo(EntProtoId other)
+    {
+        return string.Compare(Id, other.Id, StringComparison.Ordinal);
+    }
 }

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) || NoSpawn;
+
         [DataField("placement")]
         private EntityPlacementProperties PlacementProperties = new();
 

Robust.Shared/Prototypes/ProtoId.cs

@@ -1,4 +1,5 @@
-using Robust.Shared.Serialization.TypeSerializers.Implementations.Generic;
+using System;
+using Robust.Shared.Serialization.TypeSerializers.Implementations.Generic;
 
 namespace Robust.Shared.Prototypes;
 
@@ -11,7 +12,8 @@ namespace Robust.Shared.Prototypes;
 ///     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
+[Serializable]
+public readonly record struct ProtoId<T>(string Id) : IEquatable<string>, IComparable<ProtoId<T>> where T : class, IPrototype
 {
     public static implicit operator string(ProtoId<T> protoId)
     {
@@ -22,4 +24,19 @@ public readonly record struct ProtoId<T>(string Id) where T : class, IPrototype
     {
         return new ProtoId<T>(id);
     }
+
+    public static implicit operator ProtoId<T>?(string? id)
+    {
+        return id == null ? default(ProtoId<T>?) : new ProtoId<T>(id);
+    }
+
+    public bool Equals(string? other)
+    {
+        return Id == other;
+    }
+
+    public int CompareTo(ProtoId<T> other)
+    {
+        return string.Compare(Id, other.Id, StringComparison.Ordinal);
+    }
 }

Robust.Shared/Robust.Shared.csproj

@@ -19,7 +19,7 @@
     <PackageReference Include="Linguini.Bundle" Version="0.1.3" />
     <PackageReference Include="SharpZstd.Interop" Version="1.5.2-beta2" PrivateAssets="compile" />
     <PackageReference Include="SpaceWizards.Sodium" Version="0.2.1" PrivateAssets="compile" />
-    <PackageReference Include="SixLabors.ImageSharp" Version="2.1.3" />
+    <PackageReference Include="SixLabors.ImageSharp" Version="2.1.7" />
     <PackageReference Include="TerraFX.Interop.Windows" Version="10.0.20348-rc2" PrivateAssets="compile" />
   </ItemGroup>
   <ItemGroup>

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,

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

@@ -0,0 +1,42 @@
+using Robust.Shared.IoC;
+using Robust.Shared.Localization;
+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="LocId"/> types.
+/// </summary>
+[TypeSerializer]
+public sealed class LocIdSerializer : ITypeSerializer<LocId, ValueDataNode>, ITypeCopyCreator<LocId>
+{
+    public ValidationNode Validate(ISerializationManager serializationManager, ValueDataNode node, IDependencyCollection dependencies, ISerializationContext? context = null)
+    {
+        var loc = dependencies.Resolve<ILocalizationManager>();
+        if (loc.HasString(node.Value))
+            return new ValidatedValueNode(node);
+
+        return new ErrorNode(node, $"No localization message found with id {node.Value}");
+    }
+
+    public LocId Read(ISerializationManager serializationManager, ValueDataNode node, IDependencyCollection dependencies, SerializationHookContext hookCtx, ISerializationContext? context = null, InstantiationDelegate<LocId>? instanceProvider = null)
+    {
+        return new LocId(node.Value);
+    }
+
+    public DataNode Write(ISerializationManager serializationManager, LocId value, IDependencyCollection dependencies, bool alwaysWrite = false, ISerializationContext? context = null)
+    {
+        return new ValueDataNode(value);
+    }
+
+    public LocId CreateCopy(ISerializationManager serializationManager, LocId source, IDependencyCollection dependencies, SerializationHookContext hookCtx, ISerializationContext? context = null)
+    {
+        return source;
+    }
+}

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.Shared/Utility/UniqueIndexHkm.cs

@@ -43,14 +43,7 @@ namespace Robust.Shared.Utility
         public bool Add(TKey key, TValue value)
         {
             InitializedCheck();
-
-            if (_index.TryGetValue(key, out var set))
-            {
-                return set.Add(value);
-            }
-
-            _index.Add(key, new HashSet<TValue> {value});
-            return true;
+            return _index.GetOrNew(key).Add(value);
         }
 
         /// <inheritdoc />

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/VisibilityTest.cs

@@ -0,0 +1,131 @@
+using System.Linq;
+using System.Numerics;
+using System.Threading.Tasks;
+using NUnit.Framework;
+using Robust.Server.GameObjects;
+using Robust.Server.Player;
+using Robust.Shared;
+using Robust.Shared.GameObjects;
+using Robust.Shared.GameStates;
+using Robust.Shared.IoC;
+using Robust.Shared.Map;
+using Robust.Shared.Network;
+
+namespace Robust.UnitTesting.Shared.GameState;
+
+public sealed partial class VisibilityTest : RobustIntegrationTest
+{
+    /// <summary>
+    /// This tests checks that entity visibility masks are recursively applied to children.
+    /// </summary>
+    [Test]
+    public async Task UnknownEntityTest()
+    {
+        var server = StartServer();
+
+        var xforms = server.System<SharedTransformSystem>();
+        var vis = server.System<VisibilitySystem>();
+
+        const int RequiredMask = 1;
+        // All entities need to have this mask set ... which defeat the whole point of that bit?
+
+        // Spawn a stack of entities
+        int N = 6;
+        var ents = new EntityUid[N];
+        var metaComp = new MetaDataComponent[N];
+        var visComp = new VisibilityComponent[N];
+        await server.WaitPost(() =>
+        {
+            for (int i = 0; i < N; i++)
+            {
+                var ent = server.EntMan.Spawn();
+
+                ents[i] = ent;
+                metaComp[i] = server.EntMan.GetComponent<MetaDataComponent>(ent);
+                visComp[i] = server.EntMan.AddComponent<VisibilityComponent>(ent);
+
+                vis.AddLayer(ent, visComp[i], 1 << i);
+                if (i > 0)
+                    xforms.SetParent(ent, ents[i - 1]);
+            }
+        });
+
+        // Each entity's visibility mask should include the parent's mask
+        var mask = RequiredMask;
+        for (int i = 0; i < N; i++)
+        {
+            mask |= 1 << i;
+            var meta = metaComp[i];
+            Assert.That(meta.VisibilityMask, Is.EqualTo(mask));
+        }
+
+        // Adding a layer to the root entity's mask will apply it to all children
+        var extraMask = 1 << (N + 1);
+        mask = RequiredMask | extraMask;
+        vis.AddLayer(ents[0], visComp[0], extraMask);
+        for (int i = 0; i < N; i++)
+        {
+            mask |= 1 << i;
+            var meta = metaComp[i];
+            Assert.That(meta.VisibilityMask, Is.EqualTo(mask));
+        }
+
+        // Removing the removes it from all children.
+        vis.RemoveLayer(ents[0], visComp[0], extraMask);
+        mask = RequiredMask;
+        for (int i = 0; i < N; i++)
+        {
+            mask |= 1 << i;
+            var meta = metaComp[i];
+            Assert.That(meta.VisibilityMask, Is.EqualTo(mask));
+        }
+
+        // Detaching an entity from the stack updates it, and it's children's mask
+        var split = N / 2;
+        await server.WaitPost(() => xforms.SetParent(ents[split], EntityUid.Invalid));
+
+        mask = RequiredMask;
+        for (int i = 0; i < split; i++)
+        {
+            mask |= 1 << i;
+            var meta = metaComp[i];
+            Assert.That(meta.VisibilityMask, Is.EqualTo(mask));
+        }
+
+        mask = RequiredMask;
+        for (int i = split; i < N; i++)
+        {
+            mask |= 1 << i;
+            var meta = metaComp[i];
+            Assert.That(meta.VisibilityMask, Is.EqualTo(mask));
+        }
+
+        // Re-attaching the entity also updates the masks.
+        await server.WaitPost(() => xforms.SetParent(ents[split], ents[split-1]));
+        mask = RequiredMask;
+        for (int i = 0; i < N; i++)
+        {
+            mask |= 1 << i;
+            var meta = metaComp[i];
+            Assert.That(meta.VisibilityMask, Is.EqualTo(mask));
+        }
+
+        // Setting a mask on a child does not propagate upwards, only downwards
+        vis.AddLayer(ents[split], visComp[split], extraMask);
+        mask = RequiredMask;
+        for (int i = 0; i < split; i++)
+        {
+            mask |= 1 << i;
+            var meta = metaComp[i];
+            Assert.That(meta.VisibilityMask, Is.EqualTo(mask));
+        }
+
+        mask |= extraMask;
+        for (int i = split; i < N; i++)
+        {
+            mask |= 1 << i;
+            var meta = metaComp[i];
+            Assert.That(meta.VisibilityMask, Is.EqualTo(mask));
+        }
+    }
+}