Version: 210.0.2

Stretch modes are broken or something, SS14 lobby art looks wrong. Can't be arsed to debug it myself.

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 +54,80 @@ END TEMPLATE-->
 *None yet*
 
 
+## 210.0.2
+
+
+## 210.0.1
+
+### Bugfixes
+
+* Revert changes to `TextureButton` that broke style property handling.
+
+
+## 210.0.0
+
+### New features
+
+* Controls can now hook before, after, and during rendering of their children.
+* IRenderHandle is now a public API, with the caveat that it's properties and methods are unstable.
+* ButtonGroup now exposes what buttons it contains, alongside which is currently pressed.
+* OptionButton has additional styleclasses, and has a hook for modifying it's internal buttons.
+* PanelContainer.GetStyleBox() is now protected rather than private.
+* TextureButton now uses a TextureRect instead of custom drawing code.
+* TextureRect has additional style properties exposed.
+    * A new property, TextureSizeTarget, was added, which allows specifying a size in virtual pixels that the control should attempt to draw at.
+    * Stretch mode is now a style property.
+    * Scale is now a style property.
+* Avalonia.Metadata.XmlnsDefinitionAttribute is now permitted by the sandbox.
+* Add MaxDimension property to Box2 to return the higher of the Width or Height.
+* Add GetLocalPosition to convert ScreenCoordinates to coordinates relative to the control. Ignores window.
+* Add GlobalRect and GlobalPixelRect for controls to get their UIBox2i in screen terms.
+* Add dotted line drawing to DrawingHandleScreen.
+* You can use `Subs.CVar()` from an entity systems to subscribe to CVar changes. This is more convenient than `IConfigurationManager.OnValueChanged` as it automatically unsubscribes on system shutdown.
+* There is now a built-in type serializer for `DateTime`, so you can put `DateTime`s in your data fields.
+* `System.Text.Unicode.UnicodeRange` and `UnicodeRanges` are now available in the sandbox.
+
+### Bugfixes
+
+* UI drawing now properly accounts for a control's draw routine potentially mangling the current matrix.
+* UI roots now properly update when the global stylesheet is changed. They previously only did so if they had a dedicated stylesheet (which is the one case where they would be unaffected by a global sheet update.
+
+
+## 209.0.1
+
+### Bugfixes
+
+* Fix missed import from 209.0.0.
+
+
+## 209.0.0
+
+### Breaking changes
+
+* `replay.max_compressed_size` and `replay.max_uncompressed_size` CVars are now `long`.
+* Remove obsolete CoordinatesExtension for ToEntityCoordinates from GridUid / Vector2i.
+
+### New features
+
+* Add GetEntitiesOnMap / GetChildEntities to EntityLookupSystem to return components on the specified map and components with the specified parent respectively.
+* Add MaxDimension property to Box2 to return the higher of the Width or Height.
+* Add GetLocalPosition to convert ScreenCoordinates to coordinates relative to the control. Ignores window.
+* Add GlobalRect and GlobalPixelRect for controls to get their UIBox2i in screen terms.
+* Add dotted line drawing to DrawingHandleScreen.
+* `IConfigurationManager.LoadDefaultsFromTomlStream` properly does type conversions. This fixes scenarios like loading of `long` CVars.
+* Add helper methods for TileRef / Vector2i to SharedMapSystem for ToCenterCoordinates (tile center EntityCoordinates) and ToCoordinates (tile origin to EntityCoordinates).
+* Copy some of the coordinates extensions to SharedTransformSystem.
+
+### Bugfixes
+
+* Fixed integer overflows in replay max size calculation.
+* Explicitly capped `replay.replay_tick_batchSize` internally to avoid high values causing allocation failures.
+
+### Other
+
+* Important MIDI performance improvements.
+
+
 ## 208.0.0
 
 ### Breaking changes

Robust.Client/Audio/AudioOverlay.cs

@@ -39,7 +39,7 @@ public sealed class AudioOverlay : Overlay
 
     protected internal override void Draw(in OverlayDrawArgs args)
     {
-        var localPlayer = _playerManager.LocalPlayer?.ControlledEntity;
+        var localPlayer = _playerManager.LocalEntity;
 
         if (args.ViewportControl == null || localPlayer == null)
             return;

Robust.Client/Audio/AudioSystem.cs

@@ -106,8 +106,8 @@ public sealed partial class AudioSystem : SharedAudioSystem
         SubscribeNetworkEvent<PlayAudioEntityMessage>(OnEntityAudio);
         SubscribeNetworkEvent<PlayAudioPositionalMessage>(OnEntityCoordinates);
 
-        CfgManager.OnValueChanged(CVars.AudioAttenuation, OnAudioAttenuation, true);
-        CfgManager.OnValueChanged(CVars.AudioRaycastLength, OnRaycastLengthChanged, true);
+        Subs.CVar(CfgManager, CVars.AudioAttenuation, OnAudioAttenuation, true);
+        Subs.CVar(CfgManager, CVars.AudioRaycastLength, OnRaycastLengthChanged, true);
     }
 
     private void OnAudioState(EntityUid uid, AudioComponent component, ref AfterAutoHandleStateEvent args)
@@ -133,13 +133,6 @@ public sealed partial class AudioSystem : SharedAudioSystem
         _audio.SetMasterGain(value);
     }
 
-    public override void Shutdown()
-    {
-        CfgManager.UnsubValueChanged(CVars.AudioAttenuation, OnAudioAttenuation);
-        CfgManager.UnsubValueChanged(CVars.AudioRaycastLength, OnRaycastLengthChanged);
-        base.Shutdown();
-    }
-
     private void OnAudioPaused(EntityUid uid, AudioComponent component, ref EntityPausedEvent args)
     {
         component.Pause();

Robust.Client/Audio/Midi/MidiManager.cs

@@ -192,7 +192,12 @@ internal sealed partial class MidiManager : IMidiManager
             _settings["synth.midi-bank-select"].StringValue = "gm";
             //_settings["synth.verbose"].IntValue = 1; // Useful for debugging.
 
-            _parallel.AddAndInvokeParallelCountChanged(UpdateParallelCount);
+            var midiParallel = _cfgMan.GetCVar(CVars.MidiParallelism);
+            _settings["synth.polyphony"].IntValue = Math.Clamp(1024 + (int)(Math.Log2(midiParallel) * 2048), 1, 65535);
+            _settings["synth.cpu-cores"].IntValue = Math.Clamp(midiParallel, 1, 256);
+
+            _midiSawmill.Debug($"Synth Cores: {_settings["synth.cpu-cores"].IntValue}");
+            _midiSawmill.Debug($"Synth Polyphony: {_settings["synth.polyphony"].IntValue}");
         }
         catch (Exception e)
         {
@@ -201,7 +206,10 @@ internal sealed partial class MidiManager : IMidiManager
             return;
         }
 
-        _midiThread = new Thread(ThreadUpdate);
+        _midiThread = new Thread(ThreadUpdate)
+        {
+            Name = "RobustToolbox MIDI Thread"
+        };
         _midiThread.Start();
 
         _updateJob = new MidiUpdateJob()
@@ -219,18 +227,6 @@ internal sealed partial class MidiManager : IMidiManager
         FluidsynthInitialized = true;
     }
 
-    private void UpdateParallelCount()
-    {
-        if (_settings == null)
-            return;
-
-        _settings["synth.polyphony"].IntValue = Math.Clamp(1024 + (int)(Math.Log2(_parallel.ParallelProcessCount) * 2048), 1, 65535);
-        _settings["synth.cpu-cores"].IntValue = Math.Clamp(_parallel.ParallelProcessCount, 1, 256);
-
-        _midiSawmill.Debug($"Synth Cores: {_settings["synth.cpu-cores"].IntValue}");
-        _midiSawmill.Debug($"Synth Polyphony: {_settings["synth.polyphony"].IntValue}");
-    }
-
     private void LoggerDelegate(NFluidsynth.Logger.LogLevel level, string message, IntPtr data)
     {
         var rLevel = level switch

Robust.Client/Audio/Midi/MidiRenderer.cs

@@ -38,6 +38,7 @@ internal sealed class MidiRenderer : IMidiRenderer
     private readonly Synth _synth;
     private readonly Sequencer _sequencer;
     private NFluidsynth.Player? _player;
+    private int _playerTotalTicks;
     private MidiDriver? _driver;
     private byte _midiProgram = 1;
     private byte _midiBank = 1;
@@ -144,7 +145,21 @@ internal sealed class MidiRenderer : IMidiRenderer
     public bool DisableProgramChangeEvent { get; set; } = true;
 
     [ViewVariables(VVAccess.ReadWrite)]
-    public int PlayerTotalTick => _player?.GetTotalTicks ?? 0;
+    public int PlayerTotalTick
+    {
+        get
+        {
+            // GetTotalTicks is really expensive (has to iterate the entire file, not cached).
+            // Slight problem with caching it ourselves: the value only becomes available when the player loads the MIDI file.
+            // And that only happens after playback really starts, with the timer and synth and all that stuff.
+            // So we cache it "as soon as it's available", i.e. not 0.
+            // We don't care about playlists and such, so it shouldn't change anymore after.
+            if (_playerTotalTicks != 0)
+                return _playerTotalTicks;
+
+            return _playerTotalTicks = _player?.GetTotalTicks ?? 0;
+        }
+    }
 
     [ViewVariables(VVAccess.ReadWrite)]
     public int PlayerTick
@@ -339,6 +354,7 @@ internal sealed class MidiRenderer : IMidiRenderer
                 return false;
             }
 
+            _playerTotalTicks = 0;
             _player?.Dispose();
             _player = new NFluidsynth.Player(_synth);
             _player.SetPlaybackCallback(MidiPlayerEventHandler);
@@ -377,6 +393,7 @@ internal sealed class MidiRenderer : IMidiRenderer
             _player?.Join();
             _player?.Dispose();
             _player = null;
+            _playerTotalTicks = 0;
         }
 
         StopAllNotes();

Robust.Client/BaseClient.cs

@@ -229,7 +229,7 @@ namespace Robust.Client
 
             // Don't invoke PlayerLeaveServer if PlayerJoinedServer & GameStartedSetup hasn't been called yet.
             if (RunLevel > ClientRunLevel.Connecting)
-                PlayerLeaveServer?.Invoke(this, new PlayerEventArgs(_playMan.LocalPlayer?.Session));
+                PlayerLeaveServer?.Invoke(this, new PlayerEventArgs(_playMan.LocalSession));
 
             LastDisconnectReason = args.Reason;
             GameStoppedReset();

Robust.Client/Console/ClientConsoleHost.cs

@@ -188,7 +188,7 @@ namespace Robust.Client.Console
             }
 
             args.RemoveAt(0);
-            var shell = new ConsoleShell(this, session ?? _player.LocalPlayer?.Session, session == null);
+            var shell = new ConsoleShell(this, session ?? _player.LocalSession, session == null);
             var cmdArgs = args.ToArray();
 
             AnyCommandExecuted?.Invoke(shell, commandName, command, cmdArgs);
@@ -200,8 +200,7 @@ namespace Robust.Client.Console
             // When not connected to a server, you can run all local commands.
             // When connected to a server, you can only run commands according to the con group controller.
 
-            return _player.LocalPlayer == null
-                   || _player.LocalPlayer.Session.Status <= SessionStatus.Connecting
+            return _player.LocalSession is not { Status: > SessionStatus.Connecting }
                    || _conGroup.CanCommand(cmdName);
         }
 

Robust.Client/Console/Commands/ClientSpawnCommand.cs

@@ -16,8 +16,7 @@ namespace Robust.Client.Console.Commands
 
         public override void Execute(IConsoleShell shell, string argStr, string[] args)
         {
-            var controlled = _playerManager.LocalPlayer?.ControlledEntity ?? EntityUid.Invalid;
-            if (controlled == EntityUid.Invalid)
+            if (_playerManager.LocalEntity is not { } controlled)
             {
                 shell.WriteLine("You don't have an attached entity.");
                 return;

Robust.Client/Debugging/DebugPhysicsSystem.cs

@@ -420,7 +420,7 @@ namespace Robust.Client.Debugging
                 if (mapPos.MapId != args.MapId)
                     return;
 
-                var player = _playerManager.LocalPlayer?.ControlledEntity;
+                var player = _playerManager.LocalEntity;
 
                 if (!_entityManager.TryGetComponent<TransformComponent>(player, out var playerXform) ||
                     playerXform.MapID != args.MapId)

Robust.Client/GameObjects/ClientEntityManager.Network.cs

@@ -42,6 +42,8 @@ public sealed partial class ClientEntityManager
         var pending = PendingNetEntityStates.GetOrNew(nEntity);
         pending.Add((typeof(T), callerEntity));
 
+
+
         return entity.Item1;
     }
 

Robust.Client/GameObjects/ClientEntityManager.cs

@@ -221,7 +221,7 @@ namespace Robust.Client.GameObjects
         public void DispatchReceivedNetworkMsg(EntityEventArgs msg)
         {
             var sessionType = typeof(EntitySessionMessage<>).MakeGenericType(msg.GetType());
-            var sessionMsg = Activator.CreateInstance(sessionType, new EntitySessionEventArgs(_playerManager.LocalPlayer!.Session), msg)!;
+            var sessionMsg = Activator.CreateInstance(sessionType, new EntitySessionEventArgs(_playerManager.LocalSession!), msg)!;
             ReceivedSystemMessage?.Invoke(this, msg);
             ReceivedSystemMessage?.Invoke(this, sessionMsg);
         }

Robust.Client/GameObjects/EntitySystems/InputSystem.cs

@@ -105,12 +105,10 @@ namespace Robust.Client.GameObjects
         /// <param name="inputCmd">Input command to handle as predicted.</param>
         public void PredictInputCommand(IFullInputCmdMessage inputCmd)
         {
-            DebugTools.AssertNotNull(_playerManager.LocalPlayer);
-
             var keyFunc = _inputManager.NetworkBindMap.KeyFunctionName(inputCmd.InputFunctionId);
 
             Predicted = true;
-            var session = _playerManager.LocalPlayer!.Session;
+            var session = _playerManager.LocalSession;
             foreach (var handler in BindRegistry.GetHandlers(keyFunc))
             {
                 if (handler.HandleCmdMessage(EntityManager, session, inputCmd))
@@ -145,27 +143,22 @@ namespace Robust.Client.GameObjects
 
         private void GenerateInputCommand(IConsoleShell shell, string argstr, string[] args)
         {
-            var localPlayer = _playerManager.LocalPlayer;
-            if(localPlayer is null)
-                return;
-
-            var pent = localPlayer.ControlledEntity;
-            if(pent is null)
+            if (_playerManager.LocalEntity is not { } pent)
                 return;
 
             BoundKeyFunction keyFunction = new BoundKeyFunction(args[0]);
             BoundKeyState state = args[1] == "u" ? BoundKeyState.Up: BoundKeyState.Down;
 
-            var pxform = Transform(pent.Value);
+            var pxform = Transform(pent);
             var wPos = pxform.WorldPosition + new Vector2(float.Parse(args[2]), float.Parse(args[3]));
-            var coords = EntityCoordinates.FromMap(EntityManager, pent.Value, new MapCoordinates(wPos, pxform.MapID));
+            var coords = EntityCoordinates.FromMap(EntityManager, pent, new MapCoordinates(wPos, pxform.MapID));
 
             var funcId = _inputManager.NetworkBindMap.KeyFunctionID(keyFunction);
 
             var message = new FullInputCmdMessage(_timing.CurTick, _timing.TickFraction, funcId, state,
                 GetNetCoordinates(coords), new ScreenCoordinates(0, 0, default), NetEntity.Invalid);
 
-            HandleInputCommand(localPlayer.Session, keyFunction, message);
+            HandleInputCommand(_playerManager.LocalSession, keyFunction, message);
         }
 
         private void OnAttachedEntityChanged(LocalPlayerAttachedEvent message)
@@ -208,11 +201,8 @@ namespace Robust.Client.GameObjects
         /// </summary>
         public void SetEntityContextActive()
         {
-            var controlled = _playerManager.LocalPlayer?.ControlledEntity ?? EntityUid.Invalid;
-            if (controlled == EntityUid.Invalid)
-            {
+            if (_playerManager.LocalEntity is not { } controlled)
                 return;
-            }
 
             SetEntityContextActive(_inputManager, controlled);
         }

Robust.Client/GameObjects/EntitySystems/SpriteSystem.cs

@@ -62,7 +62,7 @@ namespace Robust.Client.GameObjects
             SubscribeLocalEvent<SpriteComponent, SpriteUpdateInertEvent>(QueueUpdateInert);
             SubscribeLocalEvent<SpriteComponent, ComponentInit>(OnInit);
 
-            _cfg.OnValueChanged(CVars.RenderSpriteDirectionBias, OnBiasChanged, true);
+            Subs.CVar(_cfg, CVars.RenderSpriteDirectionBias, OnBiasChanged, true);
             _sawmill = _logManager.GetSawmill("sprite");
         }
 
@@ -72,12 +72,6 @@ namespace Robust.Client.GameObjects
             QueueUpdateInert(uid, component);
         }
 
-        public override void Shutdown()
-        {
-            base.Shutdown();
-            _cfg.UnsubValueChanged(CVars.RenderSpriteDirectionBias, OnBiasChanged);
-        }
-
         private void OnBiasChanged(double value)
         {
             SpriteComponent.DirectionBias = value;

Robust.Client/GameObjects/EntitySystems/UserInterfaceSystem.cs

@@ -29,10 +29,7 @@ namespace Robust.Client.GameObjects
 
             var uiKey = ev.UiKey;
             var message = ev.Message;
-            // This should probably not happen at this point, but better make extra sure!
-            if (_playerManager.LocalPlayer != null)
-                message.Session = _playerManager.LocalPlayer.Session;
-
+            message.Session = _playerManager.LocalSession!;
             message.Entity = GetNetEntity(uid);
             message.UiKey = uiKey;
 
@@ -75,8 +72,7 @@ namespace Robust.Client.GameObjects
             boundInterface.Open();
             uiComp.OpenInterfaces[uiKey] = boundInterface;
 
-            var playerSession = _playerManager.LocalPlayer?.Session;
-            if (playerSession != null)
+            if (_playerManager.LocalSession is { } playerSession)
             {
                 uiComp.Interfaces[uiKey]._subscribedSessions.Add(playerSession);
                 RaiseLocalEvent(uid, new BoundUIOpenedEvent(uiKey, uid, playerSession), true);

Robust.Client/GameObjects/EntitySystems/VelocityDebugSystem.cs

@@ -35,7 +35,7 @@ namespace Robust.Client.GameObjects
                 return;
             }
 
-            var player = _playerManager.LocalPlayer?.ControlledEntity;
+            var player = _playerManager.LocalEntity;
 
             if (player == null || !EntityManager.TryGetComponent(player.Value, out PhysicsComponent? body))
             {

Robust.Client/GameStates/ClientGameStateManager.cs

@@ -232,9 +232,9 @@ namespace Robust.Client.GameStates
                 return default;
             }
 
-            DebugTools.AssertNotNull(_players.LocalPlayer);
+            DebugTools.Assert(_players.LocalSession != null);
 
-            var evArgs = new EntitySessionEventArgs(_players.LocalPlayer!.Session);
+            var evArgs = new EntitySessionEventArgs(_players.LocalSession);
             _pendingSystemMessages.Enqueue((_nextInputCmdSeq, _timing.CurTick, message,
                 new EntitySessionMessage<T>(evArgs, message)));
 

Robust.Client/GameStates/NetGraphOverlay.cs

@@ -313,7 +313,7 @@ namespace Robust.Client.GameStates
 
                 if (args.Length == 0)
                 {
-                    entity = _playerManager.LocalPlayer?.ControlledEntity ?? EntityUid.Invalid;
+                    entity = _playerManager.LocalEntity ?? EntityUid.Invalid;
                 }
                 else if (!NetEntity.TryParse(args[0], out var netEntity) || !_entManager.TryGetEntity(netEntity, out entity))
                 {

Robust.Client/Graphics/Drawing/DrawingHandleScreen.cs

@@ -2,6 +2,7 @@ using System;
 using System.Numerics;
 using System.Text;
 using Robust.Client.GameObjects;
+using Robust.Shared.Collections;
 using Robust.Shared.GameObjects;
 using Robust.Shared.Graphics;
 using Robust.Shared.Maths;
@@ -14,6 +15,79 @@ namespace Robust.Client.Graphics
         {
         }
 
+        /// <summary>
+        /// Simialr to DrawLine but has dashes interspersed.
+        /// </summary>
+        /// <param name="offset">Offset from the start of the line.</param>
+        /// <param name="dashSize">How long a dash is.</param>
+        /// <param name="gapSize">How long the gap between dashes is.</param>
+        public void DrawDottedLine(Vector2 from, Vector2 to, Color color, float offset = 0f, float dashSize = 8f, float gapSize = 2f)
+        {
+            var lineVector = to - from;
+
+            // No drawing for you.
+            if (lineVector.LengthSquared() < 10f * float.Epsilon)
+                return;
+
+            var lineAndGap = gapSize + dashSize;
+            var lines = new ValueList<Vector2>();
+
+            // Minimum distance.
+            if (lineVector.Length() < lineAndGap)
+            {
+                lines.Add(from);
+                lines.Add(to);
+            }
+            else
+            {
+                var maxLength = lineVector.Length();
+                var normalizedLine = lineVector.Normalized();
+                var dashVector = normalizedLine * dashSize;
+                var gapVector = normalizedLine * gapSize;
+
+                var position = from;
+                offset %= (dashSize + gapSize);
+                var length = offset;
+                var dashLength = dashSize;
+
+                // If offset is less than gap size then start with a gap
+                // otherwise start with a partial line
+                if (offset > 0f)
+                {
+                    if (offset < gapSize)
+                    {
+                        position += normalizedLine * offset;
+                        length += offset;
+                    }
+                    else
+                    {
+                        dashLength = (offset - gapSize);
+                    }
+                }
+
+                while (length < maxLength)
+                {
+                    lines.Add(position);
+
+                    position += normalizedLine * dashLength;
+                    var lengthFromStart = (position - from).Length();
+
+                    // if over length then cap the thing.
+                    if (lengthFromStart > maxLength)
+                    {
+                        position = to;
+                    }
+
+                    lines.Add(position);
+                    dashLength = dashVector.Length();
+                    position += gapVector;
+                    length = (position - from).Length();
+                }
+            }
+
+            DrawPrimitives(DrawPrimitiveTopology.LineList, lines.Span, color);
+        }
+
         public abstract void DrawRect(UIBox2 rect, Color color, bool filled = true);
 
         public abstract void DrawTextureRectRegion(Texture texture, UIBox2 rect, UIBox2? subRegion = null, Color? modulate = null);

Robust.Client/Graphics/IRenderHandle.cs

@@ -6,7 +6,10 @@ using Robust.Shared.Maths;
 
 namespace Robust.Client.Graphics
 {
-    internal interface IRenderHandle
+    /// <remarks>
+    ///     Unstable API. Likely to break hard during renderer rewrite if you rely on it.
+    /// </remarks>
+    public interface IRenderHandle
     {
         DrawingHandleScreen DrawingHandleScreen { get; }
         DrawingHandleWorld DrawingHandleWorld { get; }

Robust.Client/Graphics/Shaders/ShaderPrototype.cs

@@ -1,4 +1,4 @@
-using System;
+using System;
 using System.Collections.Generic;
 using System.Numerics;
 using Robust.Client.ResourceManagement;
@@ -69,7 +69,7 @@ namespace Robust.Client.Graphics
                     ShaderBlendMode? blend = null;
                     if (_rawBlendMode != null)
                     {
-                        if (!Enum.TryParse<ShaderBlendMode>(_rawBlendMode.ToUpper(), out var parsed))
+                        if (!Enum.TryParse<ShaderBlendMode>(_rawBlendMode, true, out var parsed))
                             Logger.Error($"invalid mode: {_rawBlendMode}");
                         else
                             blend = parsed;

Robust.Client/Input/InputManager.cs

@@ -126,7 +126,7 @@ namespace Robust.Client.Input
             {
                 try
                 {
-                    LoadKeyFile(path, true);
+                    LoadKeyFile(path, false, true);
                 }
                 catch (Exception e)
                 {
@@ -136,7 +136,7 @@ namespace Robust.Client.Input
 
             if (_resourceMan.ContentFileExists(path))
             {
-                LoadKeyFile(path, false);
+                LoadKeyFile(path, true);
             }
         }
 
@@ -496,7 +496,13 @@ namespace Robust.Client.Input
             return true;
         }
 
-        private void LoadKeyFile(ResPath file, bool userData)
+        /// <summary>
+        /// Loads a keybind file, configuring keybinds.
+        /// </summary>
+        /// <param name="file">File to load from the content package</param>
+        /// <param name="defaultRegistration">Whether or not this is a "default" keybind set. If it is, then it won't override the current configuration, only the defaults.</param>
+        /// <param name="userData">Whether or not to load from the user data directory instead of the content package.</param>
+        public void LoadKeyFile(ResPath file, bool defaultRegistration, bool userData = false)
         {
             TextReader reader;
             if (userData)
@@ -526,7 +532,7 @@ namespace Robust.Client.Input
                         continue;
                     }
 
-                    if (!userData)
+                    if (defaultRegistration)
                     {
                         _defaultRegistrations.Add(reg);
 
@@ -538,11 +544,11 @@ namespace Robust.Client.Input
                         }
                     }
 
-                    RegisterBinding(reg, markModified: userData);
+                    RegisterBinding(reg, markModified: defaultRegistration);
                 }
             }
 
-            if (userData && mapping.TryGet("leaveEmpty", out var node))
+            if (!defaultRegistration && mapping.TryGet("leaveEmpty", out var node))
             {
                 var leaveEmpty = _serialization.Read<BoundKeyFunction[]>(node, notNullableOverride: true);
 

Robust.Client/Map/TileEdgeOverlay.cs

@@ -37,7 +37,9 @@ public sealed class TileEdgeOverlay : GridOverlay
         var tileDimensions = new Vector2(tileSize, tileSize);
         var (_, _, worldMatrix, invMatrix) = xformSystem.GetWorldPositionRotationMatrixWithInv(Grid.Owner);
         args.WorldHandle.SetTransform(worldMatrix);
-        var localAABB = invMatrix.TransformBox(args.WorldBounds);
+        var bounds = args.WorldBounds;
+        bounds = new Box2Rotated(bounds.Box.Enlarged(1), bounds.Rotation, bounds.Origin);
+        var localAABB = invMatrix.TransformBox(bounds);
 
         var enumerator = mapSystem.GetLocalTilesEnumerator(Grid.Owner, Grid, localAABB, false);
 

Robust.Client/Placement/PlacementManager.cs

@@ -495,7 +495,7 @@ namespace Robust.Client.Placement
         {
             // Try to get current map.
             var map = MapId.Nullspace;
-            if (EntityManager.TryGetComponent(PlayerManager.LocalPlayer?.ControlledEntity, out TransformComponent? xform))
+            if (EntityManager.TryGetComponent(PlayerManager.LocalEntity, out TransformComponent? xform))
             {
                 map = xform.MapID;
             }
@@ -512,7 +512,7 @@ namespace Robust.Client.Placement
 
         private bool CurrentEraserMouseCoordinates(out EntityCoordinates coordinates)
         {
-            var ent = PlayerManager.LocalPlayer?.ControlledEntity ?? EntityUid.Invalid;
+            var ent = PlayerManager.LocalEntity ?? EntityUid.Invalid;
             if (ent == EntityUid.Invalid)
             {
                 coordinates = new EntityCoordinates();
@@ -640,7 +640,7 @@ namespace Robust.Client.Placement
 
             if (CurrentPermission is not {Range: > 0} ||
                 !CurrentMode.RangeRequired ||
-                PlayerManager.LocalPlayer?.ControlledEntity is not {Valid: true} controlled)
+                PlayerManager.LocalEntity is not {Valid: true} controlled)
                 return;
 
             var worldPos = EntityManager.GetComponent<TransformComponent>(controlled).WorldPosition;

Robust.Client/Placement/PlacementMode.cs

@@ -216,7 +216,7 @@ namespace Robust.Client.Placement
         {
             if (!RangeRequired)
                 return true;
-            var controlled = pManager.PlayerManager.LocalPlayer?.ControlledEntity ?? EntityUid.Invalid;
+            var controlled = pManager.PlayerManager.LocalEntity ?? EntityUid.Invalid;
             if (controlled == EntityUid.Invalid)
             {
                 return false;

Robust.Client/Player/FilterSystem.cs

@@ -10,14 +10,13 @@ namespace Robust.Client.Player
 
         public override Filter FromEntities(Filter filter, params EntityUid[] entities)
         {
-            if (_playerManager.LocalPlayer is not { } localPlayer
-                || localPlayer.Session.AttachedEntity is not {Valid: true} attachedUid)
+            if (_playerManager.LocalEntity is not {Valid: true} attachedUid)
                 return filter;
 
             foreach (var uid in entities)
             {
                 if (uid == attachedUid)
-                    filter.AddPlayer(localPlayer.Session);
+                    filter.AddPlayer(_playerManager.LocalSession!);
             }
 
             return filter;

Robust.Client/Replays/ReplayRecordingManager.cs

@@ -36,12 +36,12 @@ internal sealed class ReplayRecordingManager : SharedReplayRecordingManager
 
     private void OnRecordingStarted(MappingDataNode metadata, List<object> messages)
     {
-        if (_player.LocalPlayer == null)
+        if (_player.LocalSession == null)
             return;
 
         // Add information about the user doing the recording. This is used to set the default replay observer position
         // when playing back the replay.
-        var guid = _player.LocalPlayer.UserId.UserId.ToString();
+        var guid = _player.LocalUser.ToString();
         metadata[ReplayConstants.MetaKeyRecordedBy] = new ValueDataNode(guid);
     }
 

Robust.Client/UserInterface/Control.Layout.cs

@@ -226,6 +226,10 @@ namespace Robust.Client.UserInterface
         /// <seealso cref="Rect"/>
         public UIBox2i PixelRect => UIBox2i.FromDimensions(PixelPosition, PixelSize);
 
+        public UIBox2 GlobalRect => UIBox2.FromDimensions(GlobalPosition, _size);
+
+        public UIBox2i GlobalPixelRect => UIBox2i.FromDimensions(GlobalPixelPosition, PixelSize);
+
         /// <summary>
         /// Horizontal alignment mode.
         /// This determines how the control should be laid out horizontally
@@ -464,6 +468,14 @@ namespace Robust.Client.UserInterface
             }
         }
 
+        /// <summary>
+        /// Gets the screen coordinates position relative to the control.
+        /// </summary>
+        public Vector2 GetLocalPosition(ScreenCoordinates coordinates)
+        {
+            return coordinates.Position - GlobalPixelPosition;
+        }
+
         /// <summary>
         /// Notify the layout system that this control's <see cref="Measure"/> result may have changed
         /// and must be recalculated.

Robust.Client/UserInterface/Control.cs

@@ -545,6 +545,36 @@ namespace Robust.Client.UserInterface
             Draw(renderHandle.DrawingHandleScreen);
         }
 
+        protected internal virtual void PreRenderChildren(ref ControlRenderArguments args)
+        {
+
+        }
+
+        protected internal virtual void PostRenderChildren(ref ControlRenderArguments args)
+        {
+
+        }
+
+        protected internal virtual void RenderChildOverride(ref ControlRenderArguments args, int childIndex, Vector2i position)
+        {
+            RenderControl(ref args, childIndex, position);
+        }
+
+        public ref struct ControlRenderArguments
+        {
+            public IRenderHandle Handle;
+            public ref int Total;
+            public Vector2i Position;
+            public Color Modulate;
+            public UIBox2i? ScissorBox;
+            public ref Matrix3 CoordinateTransform;
+        }
+
+        protected void RenderControl(ref ControlRenderArguments args, int childIndex, Vector2i position)
+        {
+            UserInterfaceManagerInternal.RenderControl(args.Handle, ref args.Total, GetChild(childIndex), position, args.Modulate, args.ScissorBox, args.CoordinateTransform);
+        }
+
         public void UpdateDraw()
         {
         }

Robust.Client/UserInterface/Controls/BaseButton.cs

@@ -1,5 +1,6 @@
 using System;
 using System.Collections.Generic;
+using System.Linq;
 using Robust.Client.Audio;
 using Robust.Client.ResourceManagement;
 using Robust.Shared.ContentPack;
@@ -37,8 +38,10 @@ namespace Robust.Client.UserInterface.Controls
             get => _group;
             set
             {
+                if (value?.InternalButtons.Contains(this) ?? false)
+                    return; // No work to do.
                 // Remove from old group.
-                _group?.Buttons.Remove(this);
+                _group?.InternalButtons.Remove(this);
 
                 _group = value;
 
@@ -47,11 +50,12 @@ namespace Robust.Client.UserInterface.Controls
                     return;
                 }
 
-                value.Buttons.Add(this);
+                value.InternalButtons.Add(this);
                 ToggleMode = true;
 
-                // Set us to pressed if we're the first button.
-                Pressed = value.Buttons.Count == 0;
+                // Set us to pressed if we're the first button. Doesn't go through the setter to avoid setting off our own error check.
+                _pressed = value.InternalButtons.Count == 1;
+                DrawModeChanged();
             }
         }
 
@@ -326,7 +330,7 @@ namespace Robust.Client.UserInterface.Controls
                 return;
             }
 
-            foreach (var button in _group.Buttons)
+            foreach (var button in _group.InternalButtons)
             {
                 if (button != this && button.Pressed)
                 {
@@ -440,6 +444,9 @@ namespace Robust.Client.UserInterface.Controls
     /// </remarks>
     public sealed class ButtonGroup
     {
-        internal readonly List<BaseButton> Buttons = new();
+        internal readonly List<BaseButton> InternalButtons = new();
+        public IReadOnlyList<BaseButton> Buttons => InternalButtons;
+
+        public BaseButton? Pressed => InternalButtons.FirstOrDefault(x => x.Pressed);
     }
 }

Robust.Client/UserInterface/Controls/ItemList.cs

@@ -1,4 +1,4 @@
-using System;
+using System;
 using System.Collections;
 using System.Collections.Generic;
 using System.Diagnostics.Contracts;
@@ -9,6 +9,9 @@ using Robust.Shared.Input;
 using Robust.Shared.Maths;
 using Timer = Robust.Shared.Timing.Timer;
 
+/// <summary>
+/// Represents a scrollable list of items in a user interface.
+/// </summary>
 namespace Robust.Client.UserInterface.Controls
 {
     [Virtual]
@@ -29,6 +32,10 @@ namespace Robust.Client.UserInterface.Controls
         public const string StylePropertySelectedItemBackground = "selected-item-background";
         public const string StylePropertyDisabledItemBackground = "disabled-item-background";
 
+        /// <summary>
+        /// Gets or sets the ItemSeparation of individual list items
+        /// </summary>
+        public int ItemSeparation { get; set; } = 0; // Default value is 0px
         public int Count => _itemList.Count;
         public bool IsReadOnly => false;
 
@@ -68,8 +75,10 @@ namespace Robust.Client.UserInterface.Controls
                 itemHeight += ActualItemBackground.MinimumSize.Y * UIScale;
 
                 _totalContentHeight += (int)Math.Ceiling(itemHeight);
+                _totalContentHeight += ItemSeparation;
             }
-
+            //Remove unneeded ItemSeparation on last item.
+            _totalContentHeight -= ItemSeparation;
             _scrollBar.MaxValue = Math.Max(_scrollBar.Page, _totalContentHeight);
             _updateScrollbarVisibility();
         }
@@ -390,6 +399,9 @@ namespace Robust.Client.UserInterface.Controls
                 }
 
                 offset += itemHeight;
+
+                // Add a ItemSeparation at the bottom of each item.
+                offset += ItemSeparation;
             }
         }
 
@@ -399,7 +411,7 @@ namespace Robust.Client.UserInterface.Controls
 
             var color = ActualFontColor;
             var offsetY = (int) (box.Height - font.GetHeight(UIScale)) / 2;
-            var baseLine = new Vector2i(0, offsetY + font.GetAscent(UIScale)) + box.TopLeft;
+            var baseLine = new Vector2i(5, offsetY + font.GetAscent(UIScale)) + box.TopLeft;
 
             foreach (var rune in text.EnumerateRunes())
             {

Robust.Client/UserInterface/Controls/OptionButton.cs

@@ -12,6 +12,7 @@ namespace Robust.Client.UserInterface.Controls
     public class OptionButton : ContainerButton
     {
         public const string StyleClassOptionButton = "optionButton";
+        public const string StyleClassPopup = "optionButtonPopup";
         public const string StyleClassOptionTriangle = "optionTriangle";
         public readonly ScrollContainer OptionsScroll;
 
@@ -74,7 +75,8 @@ namespace Robust.Client.UserInterface.Controls
 
             _popup = new Popup()
             {
-                Children = { OptionsScroll }
+                Children = { new PanelContainer(), OptionsScroll },
+                StyleClasses = { StyleClassPopup }
             };
             _popup.OnPopupHide += OnPopupHide;
 
@@ -99,6 +101,11 @@ namespace Robust.Client.UserInterface.Controls
             AddItem(label, id);
         }
 
+        public virtual void ButtonOverride(Button button)
+        {
+
+        }
+
         public void AddItem(string label, int? id = null)
         {
             if (id == null)
@@ -132,6 +139,8 @@ namespace Robust.Client.UserInterface.Controls
             {
                 Select(0);
             }
+
+            ButtonOverride(button);
         }
 
         private void TogglePopup(bool show)
@@ -139,6 +148,8 @@ namespace Robust.Client.UserInterface.Controls
             if (show)
             {
                 var globalPos = GlobalPosition;
+                globalPos.Y += Size.Y + 1; // Place it below us, with a safety margin.
+                globalPos.Y -= Margin.SumVertical;
                 OptionsScroll.Measure(Window?.Size ?? Vector2Helpers.Infinity);
                 var (minX, minY) = OptionsScroll.DesiredSize;
                 var box = UIBox2.FromDimensions(globalPos, new Vector2(Math.Max(minX, Width), minY));

Robust.Client/UserInterface/Controls/PanelContainer.cs

@@ -15,13 +15,13 @@ namespace Robust.Client.UserInterface.Controls
         {
             base.Draw(handle);
 
-            var style = _getStyleBox();
+            var style = GetStyleBox();
             style?.Draw(handle, PixelSizeBox, UIScale);
         }
 
         protected override Vector2 MeasureOverride(Vector2 availableSize)
         {
-            var styleSize = _getStyleBox()?.MinimumSize ?? Vector2.Zero;
+            var styleSize = GetStyleBox()?.MinimumSize ?? Vector2.Zero;
             var measureSize = Vector2.Max(availableSize - styleSize, Vector2.Zero);
             var childSize = Vector2.Zero;
             foreach (var child in Children)
@@ -36,7 +36,7 @@ namespace Robust.Client.UserInterface.Controls
         protected override Vector2 ArrangeOverride(Vector2 finalSize)
         {
             var ourSize = UIBox2.FromDimensions(Vector2.Zero, finalSize);
-            var contentBox = _getStyleBox()?.GetContentBox(ourSize, 1) ?? ourSize;
+            var contentBox = GetStyleBox()?.GetContentBox(ourSize, 1) ?? ourSize;
 
             foreach (var child in Children)
             {
@@ -47,7 +47,7 @@ namespace Robust.Client.UserInterface.Controls
         }
 
         [System.Diagnostics.Contracts.Pure]
-        private StyleBox? _getStyleBox()
+        protected StyleBox? GetStyleBox()
         {
             if (PanelOverride != null)
             {

Robust.Client/UserInterface/IUserInterfaceManagerInternal.cs

@@ -61,6 +61,9 @@ namespace Robust.Client.UserInterface
         Vector2? CalcRelativeMousePositionFor(Control control, ScreenCoordinates mousePos);
 
         Color GetMainClearColor();
+
+        void RenderControl(IRenderHandle renderHandle, ref int total, Control control, Vector2i position, Color modulate,
+            UIBox2i? scissorBox, Matrix3 coordinateTransform);
     }
 }
 

Robust.Client/UserInterface/UserInterfaceManager.Layout.cs

@@ -132,9 +132,10 @@ internal sealed partial class UserInterfaceManager
             try
             {
                 var total = 0;
-                _render(renderHandle, ref total, root, Vector2i.Zero, Color.White, null);
                 var drawingHandle = renderHandle.DrawingHandleScreen;
-                drawingHandle.SetTransform(Vector2.Zero, Angle.Zero, Vector2.One);
+                drawingHandle.SetTransform(Matrix3.Identity);
+                RenderControl(renderHandle, ref total, root, Vector2i.Zero, Color.White, null, Matrix3.Identity);
+                drawingHandle.SetTransform(Matrix3.Identity);
                 OnPostDrawUIRoot?.Invoke(new PostDrawUIRootEventArgs(root, drawingHandle));
 
                 _prof.WriteValue("Controls rendered", ProfData.Int32(total));

Robust.Client/UserInterface/UserInterfaceManager.cs

@@ -75,7 +75,7 @@ namespace Robust.Client.UserInterface
 
                 foreach (var root in _roots)
                 {
-                    if (root.Stylesheet != null)
+                    if (root.Stylesheet == null)
                     {
                         root.StylesheetUpdateRecursive();
                     }
@@ -329,8 +329,8 @@ namespace Robust.Client.UserInterface
             }
         }
 
-        private void _render(IRenderHandle renderHandle, ref int total, Control control, Vector2i position, Color modulate,
-            UIBox2i? scissorBox)
+        public void RenderControl(IRenderHandle renderHandle, ref int total, Control control, Vector2i position, Color modulate,
+            UIBox2i? scissorBox, Matrix3 coordinateTransform)
         {
             if (!control.Visible)
             {
@@ -377,7 +377,10 @@ namespace Robust.Client.UserInterface
             total += 1;
 
             var handle = renderHandle.DrawingHandleScreen;
-            handle.SetTransform(position, Angle.Zero, Vector2.One);
+            var oldXform = handle.GetTransform();
+            var xform = oldXform;
+            xform.Multiply(Matrix3.CreateTransform(position, Angle.Zero, Vector2.One));
+            handle.SetTransform(xform);
             modulate *= control.Modulate;
 
             if (_rendering || control.AlwaysRender)
@@ -389,16 +392,32 @@ namespace Robust.Client.UserInterface
                 handle.Modulate = oldMod;
                 handle.UseShader(null);
             }
+            handle.SetTransform(oldXform);
+            var args = new Control.ControlRenderArguments()
+            {
+                Handle = renderHandle,
+                Total = ref total,
+                Modulate = modulate,
+                ScissorBox = scissorRegion,
+                CoordinateTransform = ref coordinateTransform
+            };
+
+            control.PreRenderChildren(ref args);
 
             foreach (var child in control.Children)
             {
-                _render(renderHandle, ref total, child, position + child.PixelPosition, modulate, scissorRegion);
+                var pos = position + (Vector2i) coordinateTransform.Transform(child.PixelPosition);
+                control.RenderChildOverride(ref args, child.GetPositionInParent(), pos);
             }
 
+            control.PostRenderChildren(ref args);
+
             if (clip)
             {
                 renderHandle.SetScissor(scissorBox);
             }
+
+            handle.SetTransform(oldXform);
         }
 
         public Color GetMainClearColor() => RootControl.ActualBgColor;

Robust.Server/GameObjects/EntitySystems/MapSystem.cs

@@ -28,7 +28,7 @@ namespace Robust.Server.GameObjects
             base.Initialize();
             SubscribeLocalEvent<MapGridComponent, EmptyGridEvent>(HandleGridEmpty);
 
-            _cfg.OnValueChanged(CVars.GameDeleteEmptyGrids, SetGridDeletion, true);
+            Subs.CVar(_cfg, CVars.GameDeleteEmptyGrids, SetGridDeletion, true);
         }
 
         protected override void OnMapAdd(EntityUid uid, MapComponent component, ComponentAdd args)
@@ -64,13 +64,6 @@ namespace Robust.Server.GameObjects
             return !(grid.GetAllTiles().Any());
         }
 
-        public override void Shutdown()
-        {
-            base.Shutdown();
-
-            _cfg.UnsubValueChanged(CVars.GameDeleteEmptyGrids, SetGridDeletion);
-        }
-
         private void HandleGridEmpty(EntityUid uid, MapGridComponent component, EmptyGridEvent args)
         {
             if (!_deleteEmptyGrids || TerminatingOrDeleted(uid) || HasComp<MapComponent>(uid))

Robust.Server/GameObjects/EntitySystems/PhysicsSystem.cs

@@ -20,7 +20,8 @@ namespace Robust.Server.GameObjects
         {
             base.Initialize();
             LoadMetricCVar();
-            _configurationManager.OnValueChanged(CVars.MetricsEnabled, _ => LoadMetricCVar());
+
+            Subs.CVar(_configurationManager, CVars.MetricsEnabled, _ => LoadMetricCVar());
         }
 
         private void LoadMetricCVar()

Robust.Server/GameStates/PvsSystem.cs

@@ -126,11 +126,12 @@ internal sealed partial class PvsSystem : EntitySystem
         _playerManager.PlayerStatusChanged += OnPlayerStatusChanged;
         _transform.OnGlobalMoveEvent += OnEntityMove;
 
-        _configManager.OnValueChanged(CVars.NetPVS, SetPvs, true);
-        _configManager.OnValueChanged(CVars.NetMaxUpdateRange, OnViewsizeChanged, true);
-        _configManager.OnValueChanged(CVars.NetLowLodRange, OnLodChanged, true);
-        _configManager.OnValueChanged(CVars.NetForceAckThreshold, OnForceAckChanged, true);
-        _configManager.OnValueChanged(CVars.NetPvsAsync, OnAsyncChanged, true);
+        Subs.CVar(_configManager, CVars.NetPVS, SetPvs, true);
+        Subs.CVar(_configManager, CVars.NetMaxUpdateRange, OnViewsizeChanged, true);
+        Subs.CVar(_configManager, CVars.NetLowLodRange, OnLodChanged, true);
+        Subs.CVar(_configManager, CVars.NetForceAckThreshold, OnForceAckChanged, true);
+        Subs.CVar(_configManager, CVars.NetPvsAsync, OnAsyncChanged, true);
+        Subs.CVar(_configManager, CVars.NetPvsCompressLevel, ResetParallelism, true);
 
         _serverGameStateManager.ClientAck += OnClientAck;
         _serverGameStateManager.ClientRequestFull += OnClientRequestFull;
@@ -138,7 +139,6 @@ internal sealed partial class PvsSystem : EntitySystem
         InitializeDirty();
 
         _parallelMgr.ParallelCountChanged += ResetParallelism;
-        _configManager.OnValueChanged(CVars.NetPvsCompressLevel, ResetParallelism, true);
     }
 
     public override void Shutdown()
@@ -148,10 +148,6 @@ internal sealed partial class PvsSystem : EntitySystem
         _playerManager.PlayerStatusChanged -= OnPlayerStatusChanged;
         _transform.OnGlobalMoveEvent -= OnEntityMove;
 
-        _configManager.UnsubValueChanged(CVars.NetPVS, SetPvs);
-        _configManager.UnsubValueChanged(CVars.NetMaxUpdateRange, OnViewsizeChanged);
-        _configManager.UnsubValueChanged(CVars.NetForceAckThreshold, OnForceAckChanged);
-        _configManager.UnsubValueChanged(CVars.NetPvsCompressLevel, ResetParallelism);
         _parallelMgr.ParallelCountChanged -= ResetParallelism;
 
         _serverGameStateManager.ClientAck -= OnClientAck;

Robust.Server/Physics/GridFixtureSystem.cs

@@ -64,7 +64,7 @@ namespace Robust.Server.Physics
             SubscribeNetworkEvent<RequestGridNodesMessage>(OnDebugRequest);
             SubscribeNetworkEvent<StopGridNodesMessage>(OnDebugStopRequest);
 
-            _cfg.OnValueChanged(CVars.GridSplitting, SetSplitAllowed, true);
+            Subs.CVar(_cfg, CVars.GridSplitting, SetSplitAllowed, true);
         }
 
         private void SetSplitAllowed(bool value) => SplitAllowed = value;
@@ -73,7 +73,6 @@ namespace Robust.Server.Physics
         {
             base.Shutdown();
             _subscribedSessions.Clear();
-            _cfg.UnsubValueChanged(CVars.GridSplitting, SetSplitAllowed);
         }
 
         /// <summary>

Robust.Shared.Maths/Box2.cs

@@ -75,6 +75,15 @@ namespace Robust.Shared.Maths
             get => new(Width, Height);
         }
 
+        /// <summary>
+        /// Returns the highest of width or height.
+        /// </summary>
+        public readonly float MaxDimension
+        {
+            [MethodImpl(MethodImplOptions.AggressiveInlining)]
+            get => MathF.Max(Height, Width);
+        }
+
         public readonly Vector2 Center
         {
             [MethodImpl(MethodImplOptions.AggressiveInlining)]
@@ -177,13 +186,13 @@ namespace Robust.Shared.Maths
         [Pure]
         public readonly Box2 Intersect(in Box2 other)
         {
-            var ourLeftBottom = new System.Numerics.Vector2(Left, Bottom);
-            var ourRightTop = new System.Numerics.Vector2(Right, Top);
-            var otherLeftBottom = new System.Numerics.Vector2(other.Left, other.Bottom);
-            var otherRightTop = new System.Numerics.Vector2(other.Right, other.Top);
+            var ourLeftBottom = new Vector2(Left, Bottom);
+            var ourRightTop = new Vector2(Right, Top);
+            var otherLeftBottom = new Vector2(other.Left, other.Bottom);
+            var otherRightTop = new Vector2(other.Right, other.Top);
 
-            var max = System.Numerics.Vector2.Max(ourLeftBottom, otherLeftBottom);
-            var min = System.Numerics.Vector2.Min(ourRightTop, otherRightTop);
+            var max = Vector2.Max(ourLeftBottom, otherLeftBottom);
+            var min = Vector2.Min(ourRightTop, otherRightTop);
 
             if (max.X <= min.X && max.Y <= min.Y)
                 return new Box2(max.X, max.Y, min.X, min.Y);
@@ -210,13 +219,13 @@ namespace Robust.Shared.Maths
         [Pure]
         public readonly Box2 Union(in Box2 other)
         {
-            var ourLeftBottom = new System.Numerics.Vector2(Left, Bottom);
-            var otherLeftBottom = new System.Numerics.Vector2(other.Left, other.Bottom);
-            var ourRightTop = new System.Numerics.Vector2(Right, Top);
-            var otherRightTop = new System.Numerics.Vector2(other.Right, other.Top);
+            var ourLeftBottom = new Vector2(Left, Bottom);
+            var otherLeftBottom = new Vector2(other.Left, other.Bottom);
+            var ourRightTop = new Vector2(Right, Top);
+            var otherRightTop = new Vector2(other.Right, other.Top);
 
-            var leftBottom = System.Numerics.Vector2.Min(ourLeftBottom, otherLeftBottom);
-            var rightTop = System.Numerics.Vector2.Max(ourRightTop, otherRightTop);
+            var leftBottom = Vector2.Min(ourLeftBottom, otherLeftBottom);
+            var rightTop = Vector2.Max(ourRightTop, otherRightTop);
 
             if (leftBottom.X <= rightTop.X && leftBottom.Y <= rightTop.Y)
                 return new Box2(leftBottom.X, leftBottom.Y, rightTop.X, rightTop.Y);
@@ -396,11 +405,11 @@ namespace Robust.Shared.Maths
         [Pure]
         public static Box2 Union(in Vector2 a, in Vector2 b)
         {
-            var vecA = new System.Numerics.Vector2(a.X, a.Y);
-            var vecB = new System.Numerics.Vector2(b.X, b.Y);
+            var vecA = new Vector2(a.X, a.Y);
+            var vecB = new Vector2(b.X, b.Y);
 
-            var min = System.Numerics.Vector2.Min(vecA, vecB);
-            var max = System.Numerics.Vector2.Max(vecA, vecB);
+            var min = Vector2.Min(vecA, vecB);
+            var max = Vector2.Max(vecA, vecB);
 
             return new Box2(min.X, min.Y, max.X, max.Y);
         }
@@ -412,12 +421,12 @@ namespace Robust.Shared.Maths
         [Pure]
         public readonly Box2 ExtendToContain(Vector2 vec)
         {
-            var leftBottom = new System.Numerics.Vector2(Left, Bottom);
-            var rightTop = new System.Numerics.Vector2(Right, Top);
-            var vector = new System.Numerics.Vector2(vec.X, vec.Y);
+            var leftBottom = new Vector2(Left, Bottom);
+            var rightTop = new Vector2(Right, Top);
+            var vector = new Vector2(vec.X, vec.Y);
 
-            var min = System.Numerics.Vector2.Min(vector, leftBottom);
-            var max = System.Numerics.Vector2.Max(vector, rightTop);
+            var min = Vector2.Min(vector, leftBottom);
+            var max = Vector2.Max(vector, rightTop);
 
             return new Box2(min.X, min.Y, max.X, max.Y);
         }

Robust.Shared.Maths/Easings.cs

@@ -1,13 +1,229 @@
 using System;
+using JetBrains.Annotations;
 
 namespace Robust.Shared.Maths;
 
 // Reference: https://easings.net/
 
-internal static class Easings
+/// <summary>
+///     A static class for computing easings for animations.
+///     The parameter "p" is the absolute progress of the animation between 0 and 1.
+/// </summary>
+[PublicAPI]
+public static class Easings
 {
+    #region Trig
+
+    public static float InSine(float p)
+    {
+        return 1.0f - MathF.Cos(p * MathF.PI / 2.0f);
+    }
+
+    public static float OutSine(float p)
+    {
+        return MathF.Sin(p * MathF.PI / 2);
+    }
+
+    public static float InOutSine(float p)
+    {
+        return -(MathF.Cos(MathF.PI * p) - 1.0f) / 2.0f;
+    }
+
+    #endregion
+
+    #region Polynomial
+
+    public static float InQuad(float p)
+    {
+        return p * p;
+    }
+
+    public static float OutQuad(float p)
+    {
+        return 1 - (1 - p) * (1 - p);
+    }
+
+    public static float InOutQuad(float p)
+    {
+        return p < 0.5 ? 2 * p * p : 1 - MathF.Pow(-2 * p + 2, 2) / 2;
+    }
+
+    public static float InCubic(float p)
+    {
+        return p * p * p;
+    }
+
+    public static float OutCubic(float p)
+    {
+        return 1 - MathF.Pow(1 - p, 3);
+    }
+
+    public static float InOutCubic(float p)
+    {
+        return p < 0.5 ? 4 * p * p * p : 1 - MathF.Pow(-2 * p + 2, 3) / 2;
+    }
+
+    public static float InQuart(float p)
+    {
+        return p * p * p * p;
+    }
+
+    public static float OutQuart(float p)
+    {
+        return 1 - MathF.Pow(1 - p, 4);
+    }
+
+    public static float InOutQuart(float p)
+    {
+        return p < 0.5 ? 8 * p * p * p * p : 1 - MathF.Pow(-2 * p + 2, 4) / 2;
+    }
+
+    public static float InQuint(float p)
+    {
+        return p * p * p * p * p;
+    }
+
+    public static float OutQuint(float p)
+    {
+        return 1 - MathF.Pow(1 - p, 5);
+    }
+
     public static float InOutQuint(float p)
     {
-        return p < 0.5f ? (16 * p * p * p * p * p) : 1 - MathF.Pow(-2 * p + 2, 5) / 2;
+        return p < 0.5f ? 16 * p * p * p * p * p : 1 - MathF.Pow(-2 * p + 2, 5) / 2;
     }
+
+    #endregion
+
+    #region Other
+
+    public static float InExpo(float p)
+    {
+        return p == 0 ? 0 : MathF.Pow(2, 10 * p - 10);
+    }
+
+    public static float OutExpo(float p)
+    {
+        return Math.Abs(p - 1) < 0.0001f ? 1 : 1 - MathF.Pow(2, -10 * p);
+    }
+
+    public static float InOutExpo(float p)
+    {
+        return p == 0.0f
+            ? 0
+            : Math.Abs(p - 1) < 0.0001f
+                ? 1
+                : p < 0.5f
+                    ? MathF.Pow(2, 20 * p - 10) / 2
+                    : (2 - MathF.Pow(2, -20 * p + 10)) / 2;
+    }
+
+    public static float InCirc(float p)
+    {
+        return 1 - MathF.Sqrt(1 - MathF.Pow(p, 2));
+    }
+
+    public static float OutCirc(float p)
+    {
+        return MathF.Sqrt(1 - MathF.Pow(p - 1, 2));
+    }
+
+    public static float InOutCirc(float p)
+    {
+        return p < 0.5
+            ? (1 - MathF.Sqrt(1 - MathF.Pow(2 * p, 2))) / 2
+            : (MathF.Sqrt(1 - MathF.Pow(-2 * p + 2, 2)) + 1) / 2;
+    }
+
+    public static float InBack(float p)
+    {
+        var c1 = 1.70158f;
+        var c3 = c1 + 1;
+
+        return c3 * p * p * p - c1 * p * p;
+    }
+
+    public static float OutBack(float p)
+    {
+        const float c1 = 1.70158f;
+        const float c3 = c1 + 1;
+
+        return 1 + c3 * MathF.Pow(p - 1, 3) + c1 * MathF.Pow(p - 1, 2);
+    }
+
+    public static float InOutBack(float p)
+    {
+        const float c1 = 1.70158f;
+        const float c2 = c1 * 1.525f;
+
+        return p < 0.5
+            ? MathF.Pow(2 * p, 2) * ((c2 + 1) * 2 * p - c2) / 2
+            : (MathF.Pow(2 * p - 2, 2) * ((c2 + 1) * (p * 2 - 2) + c2) + 2) / 2;
+    }
+
+    /// <remarks>
+    ///     elastic in, not "inelastic"
+    /// </remarks>
+    public static float InElastic(float p)
+    {
+        const float c4 = 2 * MathF.PI / 3;
+
+        return p == 0
+            ? 0
+            : Math.Abs(p - 1) < 0.0001f
+                ? 1
+                : -MathF.Pow(2, 10 * p - 10) * MathF.Sin((p * 10 - 10.75f) * c4);
+    }
+
+    public static float OutElastic(float p)
+    {
+        const float c4 = 2.0f * MathF.PI / 3.0f;
+
+        return p == 0
+            ? 0
+            : Math.Abs(p - 1) < 0.0001f
+                ? 1
+                : MathF.Pow(2, -10 * p) * MathF.Sin((p * 10.0f - 0.75f) * c4) + 1.0f;
+    }
+
+    public static float InOutElastic(float p)
+    {
+        const float c5 = 2.0f * MathF.PI / 4.5f;
+
+        return p == 0
+            ? 0
+            : Math.Abs(p - 1) < 0.0001f
+                ? 1
+                : p < 0.5
+                    ? -(MathF.Pow(2, 20 * p - 10) * MathF.Sin((20.0f * p - 11.125f) * c5)) / 2.0f
+                    : MathF.Pow(2, -20.0f * p + 10.0f) * MathF.Sin((20.0f * p - 11.125f) * c5) / 2.0f + 1.0f;
+    }
+
+    public static float InBounce(float p)
+    {
+        return 1 - OutBounce(1 - p);
+    }
+
+    public static float OutBounce(float p)
+    {
+        const float n1 = 7.5625f;
+        const float d1 = 2.75f;
+
+        if (p < 1 / d1) return n1 * p * p;
+
+        if (p < 2 / d1) return n1 * (p -= 1.5f / d1) * p + 0.75f;
+
+        if (p < 2.5 / d1) return n1 * (p -= 2.25f / d1) * p + 0.9375f;
+
+        return n1 * (p -= 2.625f / d1) * p + 0.984375f;
+    }
+
+    public static float InOutBounce(float p)
+    {
+        return p < 0.5
+            ? (1 - OutBounce(1 - 2 * p)) / 2
+            : (1 + OutBounce(2 * p - 1)) / 2;
+    }
+
+    #endregion
 }

Robust.Shared/Audio/Systems/SharedAudioSystem.cs

@@ -50,17 +50,11 @@ public abstract partial class SharedAudioSystem : EntitySystem
         base.Initialize();
         InitializeEffect();
         ZOffset = CfgManager.GetCVar(CVars.AudioZOffset);
-        CfgManager.OnValueChanged(CVars.AudioZOffset, SetZOffset);
+        Subs.CVar(CfgManager, CVars.AudioZOffset, SetZOffset);
         SubscribeLocalEvent<AudioComponent, ComponentGetStateAttemptEvent>(OnAudioGetStateAttempt);
         SubscribeLocalEvent<AudioComponent, EntityUnpausedEvent>(OnAudioUnpaused);
     }
 
-    public override void Shutdown()
-    {
-        base.Shutdown();
-        CfgManager.UnsubValueChanged(CVars.AudioZOffset, SetZOffset);
-    }
-
     protected void SetZOffset(float value)
     {
         ZOffset = value;

Robust.Shared/CVars.cs

@@ -1239,7 +1239,7 @@ namespace Robust.Shared
         /// Enable Discord rich presence integration.
         /// </summary>
         public static readonly CVarDef<bool> DiscordEnabled =
-            CVarDef.Create("discord.enabled", true, CVar.CLIENTONLY);
+            CVarDef.Create("discord.enabled", true, CVar.CLIENTONLY | CVar.ARCHIVE);
 
         public static readonly CVarDef<string> DiscordRichPresenceMainIconId =
             CVarDef.Create("discord.rich_main_icon_id", "devstation", CVar.SERVER | CVar.REPLICATED);
@@ -1323,6 +1323,16 @@ namespace Robust.Shared
         public static readonly CVarDef<float> MidiVolume =
             CVarDef.Create("midi.volume", 0.50f, CVar.CLIENTONLY | CVar.ARCHIVE);
 
+        /// <summary>
+        /// Controls amount of CPU cores and (by extension) polyphony for Fluidsynth.
+        /// </summary>
+        /// <remarks>
+        /// You probably don't want to set this to be multithreaded, the way Fluidsynth's multithreading works is
+        /// probably worse-than-nothing for Robust's usage.
+        /// </remarks>
+        public static readonly CVarDef<int> MidiParallelism =
+            CVarDef.Create("midi.parallelism", 1, CVar.CLIENTONLY | CVar.ARCHIVE);
+
         /*
          * HUB
          * CVars related to public master server hub
@@ -1487,14 +1497,14 @@ namespace Robust.Shared
         /// <summary>
         /// Maximum compressed size of a replay recording (in kilobytes) before recording automatically stops.
         /// </summary>
-        public static readonly CVarDef<int> ReplayMaxCompressedSize = CVarDef.Create("replay.max_compressed_size",
-            1024 * 256, CVar.ARCHIVE);
+        public static readonly CVarDef<long> ReplayMaxCompressedSize = CVarDef.Create("replay.max_compressed_size",
+            1024L * 256, CVar.ARCHIVE);
 
         /// <summary>
         /// Maximum uncompressed size of a replay recording (in kilobytes) before recording automatically stops.
         /// </summary>
-        public static readonly CVarDef<int> ReplayMaxUncompressedSize = CVarDef.Create("replay.max_uncompressed_size",
-            1024 * 1024, CVar.ARCHIVE);
+        public static readonly CVarDef<long> ReplayMaxUncompressedSize = CVarDef.Create("replay.max_uncompressed_size",
+            1024L * 1024, CVar.ARCHIVE);
 
         /// <summary>
         /// Uncompressed size of individual files created by the replay (in kilobytes), where each file contains data

Robust.Shared/Configuration/ConfigurationManager.cs

@@ -113,10 +113,46 @@ namespace Robust.Shared.Configuration
         {
             var loaded = new HashSet<string>();
 
-            foreach (var (cvar, value) in ParseCVarValuesFromToml(stream))
+            var callbackEvents = new ValueList<ValueChangedInvoke>();
+
+            // Ensure callbacks are raised OUTSIDE the write lock.
+            using (Lock.WriteGuard())
             {
-                loaded.Add(cvar);
-                OverrideDefault(cvar, value);
+                foreach (var (cVarName, value) in ParseCVarValuesFromToml(stream))
+                {
+                    if (!_configVars.TryGetValue(cVarName, out var cVar) || !cVar.Registered)
+                    {
+                        _sawmill.Error($"Trying to set unregistered variable '{cVarName}'");
+                        continue;
+                    }
+
+                    var convertedValue = value;
+                    if (!cVar.DefaultValue.GetType().IsEnum && cVar.DefaultValue.GetType() != value.GetType())
+                    {
+                        try
+                        {
+                            convertedValue = ConvertToCVarType(value, cVar.DefaultValue.GetType());
+                        }
+                        catch
+                        {
+                            _sawmill.Error($"Override TOML parsed cvar does not match registered cvar type. Name: {cVarName}. Code Type: {cVar.DefaultValue.GetType()}. Toml type: {value.GetType()}");
+                            continue;
+                        }
+                    }
+
+                    cVar.DefaultValue = value;
+
+                    if (cVar.OverrideValue == null && cVar.Value == null)
+                    {
+                        if (SetupInvokeValueChanged(cVar, convertedValue) is { } invoke)
+                            callbackEvents.Add(invoke);
+                    }
+                }
+            }
+
+            foreach (var callback in callbackEvents)
+            {
+                InvokeValueChanged(callback);
             }
 
             return loaded;
@@ -303,8 +339,7 @@ namespace Robust.Shared.Configuration
                 {
                     try
                     {
-                        // try convert thing like int to float.
-                        cVar.Value = Convert.ChangeType(cVar.Value, type);
+                        cVar.Value = ConvertToCVarType(cVar.Value, type);
                     }
                     catch
                     {
@@ -711,6 +746,26 @@ namespace Robust.Shared.Configuration
             }
         }
 
+        /// <summary>
+        /// Try to convert a compatible value to the actual registration type of a CVar.
+        /// </summary>
+        /// <remarks>
+        /// When CVars are parsed from TOML, their in-code type is not known.
+        /// This function does the necessary conversions from e.g. int to long.
+        /// </remarks>
+        /// <param name="value">
+        /// The value to convert.
+        /// This must be a simple type like strings or integers.
+        /// </param>
+        /// <param name="cVar">
+        /// The registration type of the CVar.
+        /// </param>
+        /// <returns></returns>
+        private static object ConvertToCVarType(object value, Type cVar)
+        {
+            return Convert.ChangeType(value, cVar);
+        }
+
         /// <summary>
         ///     Holds the data for a single configuration variable.
         /// </summary>

Robust.Shared/ContentPack/Sandbox.yml

@@ -73,6 +73,9 @@ WhitelistedNamespaces:
 # * The API is not *relevant* to content. e.g. System.Type.IsAnsiClass.
 # * I am lazy these API lists are huge dude.
 Types:
+  Avalonia.Metadata:
+    XmlnsDefinitionAttribute:
+      All: True
   NetSerializer:
     NetListAsArray`1:
       Fields:
@@ -626,6 +629,7 @@ Types:
       - "System.Text.Encoding get_UTF7()"
       - "System.Text.Encoding get_UTF8()"
       - "System.Text.Encoding get_UTF32()"
+      - "System.Text.Encoding GetEncoding(string)"
     NormalizationForm: { } # Enum
     Rune: { All: True }
     StringBuilder:
@@ -716,6 +720,9 @@ Types:
         ChunkEnumerator: { All: True }
         AppendInterpolatedStringHandler: { All: True }
     StringRuneEnumerator: { All: True }
+  System.Text.Unicode:
+    UnicodeRange: { All: True }
+    UnicodeRanges: { All: True }
   System.Threading.Tasks:
     Task: { All: True }
     Task`1: { All: True }

Robust.Shared/GameObjects/EntitySystem.Subscriptions.cs

@@ -1,12 +1,12 @@
 using System;
-using System.Collections.Generic;
 using JetBrains.Annotations;
+using Robust.Shared.Collections;
 
 namespace Robust.Shared.GameObjects
 {
     public abstract partial class EntitySystem
     {
-        private List<SubBase>? _subscriptions;
+        private ValueList<SubBase> _subscriptions;
 
         /// <summary>
         /// A handle to allow subscription on this entity system's behalf.
@@ -84,7 +84,6 @@ namespace Robust.Shared.GameObjects
         {
             EntityManager.EventBus.SubscribeEvent(src, this, handler, GetType(), before, after);
 
-            _subscriptions ??= new();
             _subscriptions.Add(new SubBroadcast<T>(src));
         }
 
@@ -96,7 +95,6 @@ namespace Robust.Shared.GameObjects
         {
             EntityManager.EventBus.SubscribeEvent(src, this, handler, GetType(), before, after);
 
-            _subscriptions ??= new();
             _subscriptions.Add(new SubBroadcast<T>(src));
         }
 
@@ -108,7 +106,6 @@ namespace Robust.Shared.GameObjects
         {
             EntityManager.EventBus.SubscribeSessionEvent(src, this, handler, GetType(), before, after);
 
-            _subscriptions ??= new();
             _subscriptions.Add(new SubBroadcast<EntitySessionMessage<T>>(src));
         }
 
@@ -122,7 +119,6 @@ namespace Robust.Shared.GameObjects
         {
             EntityManager.EventBus.SubscribeLocalEvent(handler, GetType(), before, after);
 
-            _subscriptions ??= new();
             _subscriptions.Add(new SubLocal<TComp, TEvent>());
         }
 
@@ -134,7 +130,6 @@ namespace Robust.Shared.GameObjects
         {
             EntityManager.EventBus.SubscribeLocalEvent(handler, GetType(), before, after);
 
-            _subscriptions ??= new();
             _subscriptions.Add(new SubLocal<TComp, TEvent>());
         }
 
@@ -146,21 +141,17 @@ namespace Robust.Shared.GameObjects
         {
             EntityManager.EventBus.SubscribeLocalEvent(handler, GetType(), before, after);
 
-            _subscriptions ??= new();
             _subscriptions.Add(new SubLocal<TComp, TEvent>());
         }
 
         private void ShutdownSubscriptions()
         {
-            if (_subscriptions == null)
-                return;
-
             foreach (var sub in _subscriptions)
             {
                 sub.Unsubscribe(this, EntityManager.EventBus);
             }
 
-            _subscriptions = null;
+            _subscriptions = default;
         }
 
         /// <summary>
@@ -232,6 +223,19 @@ namespace Robust.Shared.GameObjects
             {
                 System.SubscribeLocalEvent(handler, before, after);
             }
+
+            /// <summary>
+            /// Register an action to be ran when this entity system is shut down.
+            /// </summary>
+            /// <remarks>
+            /// This can be used by extension methods for <see cref="Subscriptions"/>
+            /// to unsubscribe from from external sources such as CVars.
+            /// </remarks>
+            /// <param name="action">An action to be ran when the entity system is shut down.</param>
+            public void RegisterUnsubscription(Action action)
+            {
+                System._subscriptions.Add(new SubAction(action));
+            }
         }
 
         private abstract class SubBase
@@ -261,5 +265,13 @@ namespace Robust.Shared.GameObjects
                 bus.UnsubscribeLocalEvent<TComp, TBase>();
             }
         }
+
+        private sealed class SubAction(Action action) : SubBase
+        {
+            public override void Unsubscribe(EntitySystem sys, IEventBus bus)
+            {
+                action();
+            }
+        }
     }
 }

Robust.Shared/GameObjects/EntitySystem.cs

@@ -1,6 +1,7 @@
 using System;
 using System.Collections.Generic;
 using System.Diagnostics.CodeAnalysis;
+using System.Globalization;
 using System.Linq;
 using JetBrains.Annotations;
 using Robust.Shared.IoC;
@@ -41,8 +42,16 @@ namespace Robust.Shared.GameObjects
                     name = name.Substring(0, name.Length - "System".Length);
 
                 // Convert CamelCase to snake_case
-                name = string.Concat(name.Select(x => char.IsUpper(x) ? $"_{char.ToLower(x)}" : x.ToString()));
-                name = name.Trim('_');
+                // Ignore if all uppercase, assume acronym (e.g. NPC or HTN)
+                if (name.All(char.IsUpper))
+                {
+                    name = name.ToLower(CultureInfo.InvariantCulture);
+                }
+                else
+                {
+                    name = string.Concat(name.Select(x => char.IsUpper(x) ? $"_{char.ToLower(x)}" : x.ToString()));
+                    name = name.Trim('_');
+                }
 
                 return $"system.{name}";
             }

Robust.Shared/GameObjects/EntitySystemSubscriptionExt.cs

@@ -0,0 +1,130 @@
+using System;
+using Robust.Shared.Configuration;
+
+namespace Robust.Shared.GameObjects;
+
+/// <summary>
+/// Extra subscription helpers for <see cref="EntitySystem"/> that are not part of the core entity system behavior.
+/// </summary>
+public static class EntitySystemSubscriptionExt
+{
+    /// <summary>
+    /// Listen for an event for if the config value changes.
+    /// </summary>
+    /// <remarks>
+    /// This is an O(n) operation.
+    /// </remarks>
+    /// <param name="subs">
+    /// The entity system subscriptions.
+    /// Call this with <see cref="EntitySystem.Subscriptions"/>.
+    /// </param>
+    /// <param name="cfg">The configuration manager.</param>
+    /// <param name="name">The name of the CVar to listen for.</param>
+    /// <param name="onValueChanged">The delegate to run when the value was changed.</param>
+    /// <param name="invokeImmediately">
+    /// Whether to run the callback immediately inw this method. Can help reduce boilerplate
+    /// </param>
+    /// <typeparam name="T">The type of value contained in this CVar.</typeparam>
+    public static void CVar<T>(
+        this EntitySystem.Subscriptions subs,
+        IConfigurationManager cfg,
+        string name,
+        Action<T> onValueChanged,
+        bool invokeImmediately = false)
+        where T : notnull
+    {
+        cfg.OnValueChanged(name, onValueChanged, invokeImmediately);
+
+        subs.RegisterUnsubscription(() => cfg.UnsubValueChanged(name, onValueChanged));
+    }
+
+    /// <summary>
+    /// Listen for an event for if the config value changes.
+    /// </summary>
+    /// <remarks>
+    /// This is an O(n) operation.
+    /// </remarks>
+    /// <param name="subs">
+    /// The entity system subscriptions.
+    /// Call this with <see cref="EntitySystem.Subscriptions"/>.
+    /// </param>
+    /// <param name="cfg">The configuration manager.</param>
+    /// <param name="cVar">The CVar to listen for.</param>
+    /// <param name="onValueChanged">The delegate to run when the value was changed.</param>
+    /// <param name="invokeImmediately">
+    /// Whether to run the callback immediately in this method. Can help reduce boilerplate
+    /// </param>
+    /// <typeparam name="T">The type of value contained in this CVar.</typeparam>
+    public static void CVar<T>(
+        this EntitySystem.Subscriptions subs,
+        IConfigurationManager cfg,
+        CVarDef<T> cVar,
+        Action<T> onValueChanged,
+        bool invokeImmediately = false)
+        where T : notnull
+    {
+        cfg.OnValueChanged(cVar, onValueChanged, invokeImmediately);
+
+        subs.RegisterUnsubscription(() => cfg.UnsubValueChanged(cVar, onValueChanged));
+    }
+
+    /// <summary>
+    /// Listen for an event for if the config value changes.
+    /// </summary>
+    /// <remarks>
+    /// This is an O(n) operation.
+    /// </remarks>
+    /// <param name="subs">
+    /// The entity system subscriptions.
+    /// Call this with <see cref="EntitySystem.Subscriptions"/>.
+    /// </param>
+    /// <param name="cfg">The configuration manager.</param>
+    /// <param name="name">The name of the CVar to listen for.</param>
+    /// <param name="onValueChanged">The delegate to run when the value was changed.</param>
+    /// <param name="invokeImmediately">
+    /// Whether to run the callback immediately in this method. Can help reduce boilerplate
+    /// </param>
+    /// <typeparam name="T">The type of value contained in this CVar.</typeparam>
+    public static void CVar<T>(
+        this EntitySystem.Subscriptions subs,
+        IConfigurationManager cfg,
+        string name,
+        CVarChanged<T> onValueChanged,
+        bool invokeImmediately = false)
+        where T : notnull
+    {
+        cfg.OnValueChanged(name, onValueChanged, invokeImmediately);
+
+        subs.RegisterUnsubscription(() => cfg.UnsubValueChanged(name, onValueChanged));
+    }
+
+    /// <summary>
+    /// Listen for an event for if the config value changes.
+    /// </summary>
+    /// <remarks>
+    /// This is an O(n) operation.
+    /// </remarks>
+    /// <param name="subs">
+    /// The entity system subscriptions.
+    /// Call this with <see cref="EntitySystem.Subscriptions"/>.
+    /// </param>
+    /// <param name="cfg">The configuration manager.</param>
+    /// <param name="cVar">The CVar to listen for.</param>
+    /// <param name="onValueChanged">The delegate to run when the value was changed.</param>
+    /// <param name="invokeImmediately">
+    /// Whether to run the callback immediately in this method. Can help reduce boilerplate
+    /// </param>
+    /// <typeparam name="T">The type of value contained in this CVar.</typeparam>
+    public static void CVar<T>(
+        this EntitySystem.Subscriptions subs,
+        IConfigurationManager cfg,
+        CVarDef<T> cVar,
+        CVarChanged<T> onValueChanged,
+        bool invokeImmediately = false)
+        where T : notnull
+    {
+        cfg.OnValueChanged(cVar, onValueChanged, invokeImmediately);
+
+        subs.RegisterUnsubscription(() => cfg.UnsubValueChanged(cVar, onValueChanged));
+    }
+}

Robust.Shared/GameObjects/Systems/EntityLookupSystem.ComponentQueries.cs

@@ -703,16 +703,75 @@ public sealed partial class EntityLookupSystem
         GetEntitiesIntersecting(mapId, shape, transform, entities, flags);
     }
 
+    /// <summary>
+    /// Gets entities with the specified component with the specified map.
+    /// </summary>
+    public void GetEntitiesOnMap<TComp1>(MapId mapId, HashSet<Entity<TComp1>> entities) where TComp1 : IComponent
+    {
+        var query = AllEntityQuery<TComp1, TransformComponent>();
+
+        while (query.MoveNext(out var uid, out var comp, out var xform))
+        {
+            if (xform.MapID != mapId)
+                continue;
+
+            entities.Add((uid, comp));
+        }
+    }
+
+    /// <summary>
+    /// Gets entities with the specified component with the specified parent.
+    /// </summary>
+    public void GetEntitiesOnMap<TComp1, TComp2>(MapId mapId, HashSet<Entity<TComp1, TComp2>> entities)
+        where TComp1 : IComponent
+        where TComp2 : IComponent
+    {
+        var query = AllEntityQuery<TComp1, TComp2, TransformComponent>();
+
+        while (query.MoveNext(out var uid, out var comp, out var comp2, out var xform))
+        {
+            if (xform.MapID != mapId)
+                continue;
+
+            entities.Add((uid, comp, comp2));
+        }
+    }
+
     #endregion
 
-    private readonly record struct GridQueryCompState<T>(
-        HashSet<Entity<IComponent>> Intersecting,
-        IPhysShape Shape,
-        Transform Transform,
-        EntityLookupSystem Lookup,
-        LookupFlags Flags,
-        EntityQuery<T> Query
-    ) where T : IComponent;
+    /// <summary>
+    /// Gets entities with the specified component with the specified parent.
+    /// </summary>
+    public void GetChildEntities<TComp1>(EntityUid parentUid, HashSet<Entity<TComp1>> entities) where TComp1 : IComponent
+    {
+        var query = AllEntityQuery<TComp1, TransformComponent>();
+
+        while (query.MoveNext(out var uid, out var comp, out var xform))
+        {
+            if (xform.ParentUid != parentUid)
+                continue;
+
+            entities.Add((uid, comp));
+        }
+    }
+
+    /// <summary>
+    /// Gets entities with the specified component with the specified parent.
+    /// </summary>
+    public void GetChildEntities<TComp1, TComp2>(EntityUid parentUid, HashSet<Entity<TComp1, TComp2>> entities)
+        where TComp1 : IComponent
+        where TComp2 : IComponent
+    {
+        var query = AllEntityQuery<TComp1, TComp2, TransformComponent>();
+
+        while (query.MoveNext(out var uid, out var comp, out var comp2, out var xform))
+        {
+            if (xform.ParentUid != parentUid)
+                continue;
+
+            entities.Add((uid, comp, comp2));
+        }
+    }
 
     private readonly record struct GridQueryState<T>(
         HashSet<Entity<T>> Intersecting,

Robust.Shared/GameObjects/Systems/SharedGridFixtureSystem.cs

@@ -36,8 +36,8 @@ namespace Robust.Shared.GameObjects
             base.Initialize();
             UpdatesBefore.Add(typeof(SharedBroadphaseSystem));
 
-            _cfg.OnValueChanged(CVars.GenerateGridFixtures, SetEnabled, true);
-            _cfg.OnValueChanged(CVars.GridFixtureEnlargement, SetEnlargement, true);
+            Subs.CVar(_cfg, CVars.GenerateGridFixtures, SetEnabled, true);
+            Subs.CVar(_cfg, CVars.GridFixtureEnlargement, SetEnlargement, true);
 
             SubscribeLocalEvent<GridInitializeEvent>(OnGridInit);
             SubscribeLocalEvent<RegenerateGridBoundsEvent>(OnGridBoundsRegenerate);
@@ -58,14 +58,6 @@ namespace Robust.Shared.GameObjects
             _map.RegenerateCollision(ev.EntityUid, grid, _map.GetMapChunks(ev.EntityUid, grid).Values.ToHashSet());
         }
 
-        public override void Shutdown()
-        {
-            base.Shutdown();
-
-            _cfg.UnsubValueChanged(CVars.GenerateGridFixtures, SetEnabled);
-            _cfg.UnsubValueChanged(CVars.GridFixtureEnlargement, SetEnlargement);
-        }
-
         private void SetEnabled(bool value) => _enabled = value;
 
         private void SetEnlargement(float value) => _fixtureEnlargement = value;

Robust.Shared/GameObjects/Systems/SharedMapSystem.Coordinates.cs

@@ -0,0 +1,83 @@
+using JetBrains.Annotations;
+using Robust.Shared.Map;
+using Robust.Shared.Map.Components;
+using Robust.Shared.Maths;
+
+namespace Robust.Shared.GameObjects;
+
+public abstract partial class SharedMapSystem
+{
+    /// <summary>
+    /// If the supplied coordinates intersects a grid will align with the tile center, otherwise returns the coordinates.
+    /// </summary>
+    /// <param name="coordinates"></param>
+    /// <returns></returns>
+    [Pure]
+    public EntityCoordinates AlignToGrid(EntityCoordinates coordinates)
+    {
+        // Check if the parent is already a grid.
+        if (_gridQuery.TryGetComponent(coordinates.EntityId, out var gridComponent))
+        {
+            var tile = CoordinatesToTile(coordinates.EntityId, gridComponent, coordinates);
+            return ToCenterCoordinates(coordinates.EntityId, tile, gridComponent);
+        }
+
+        // Check if mappos intersects a grid.
+        var mapPos = coordinates.ToMap(EntityManager, _transform);
+
+        if (_mapInternal.TryFindGridAt(mapPos, out var gridUid, out gridComponent))
+        {
+            var tile = CoordinatesToTile(gridUid, gridComponent, coordinates);
+            return ToCenterCoordinates(gridUid, tile, gridComponent);
+        }
+
+        // No grid so just return it.
+        return coordinates;
+    }
+
+    /// <summary>
+    /// Converts a tileRef to EntityCoordinates.
+    /// </summary>
+    [Pure]
+    public EntityCoordinates ToCoordinates(TileRef tileRef, MapGridComponent? gridComponent = null)
+    {
+        return ToCoordinates(tileRef.GridUid, tileRef.GridIndices, gridComponent);
+    }
+
+    /// <summary>
+    /// Converts a tileRef to EntityCoordinates.
+    /// </summary>
+    [Pure]
+    public EntityCoordinates ToCoordinates(EntityUid gridUid, Vector2i tile, MapGridComponent? gridComponent = null)
+    {
+        if (!_gridQuery.Resolve(gridUid, ref gridComponent))
+        {
+            return EntityCoordinates.Invalid;
+        }
+
+        return new EntityCoordinates(gridUid, tile * gridComponent.TileSize);
+    }
+
+    /// <summary>
+    /// Converts a tileRef to EntityCoordinates for the center of the tile.
+    /// </summary>
+    [Pure]
+    public EntityCoordinates ToCenterCoordinates(TileRef tileRef, MapGridComponent? gridComponent = null)
+    {
+        return ToCenterCoordinates(tileRef.GridUid, tileRef.GridIndices, gridComponent);
+    }
+
+    /// <summary>
+    /// Converts a tileRef to EntityCoordinates for the center of the tile.
+    /// </summary>
+    [Pure]
+    public EntityCoordinates ToCenterCoordinates(EntityUid gridUid, Vector2i tile, MapGridComponent? gridComponent = null)
+    {
+        if (!_gridQuery.Resolve(gridUid, ref gridComponent))
+        {
+            return EntityCoordinates.Invalid;
+        }
+
+        return new EntityCoordinates(gridUid, tile * gridComponent.TileSize + gridComponent.TileSizeHalfVector);
+    }
+}

Robust.Shared/GameObjects/Systems/SharedMapSystem.Grid.cs

@@ -189,7 +189,7 @@ public abstract partial class SharedMapSystem
         if (xform.MapUid == null && meta.EntityLifeStage < EntityLifeStage.Terminating && _netManager.IsServer)
             Log.Error($"Grid {ToPrettyString(uid, meta)} was moved to nullspace! AAAAAAAAAAAAAAAAAAAAAAAAA! {Environment.StackTrace}");
 
-        DebugTools.Assert(!HasComp<MapComponent>(uid));
+        DebugTools.Assert(!_mapQuery.HasComponent(uid));
 
         if (xform.ParentUid != xform.MapUid && meta.EntityLifeStage < EntityLifeStage.Terminating  && _netManager.IsServer)
         {
@@ -454,7 +454,7 @@ public abstract partial class SharedMapSystem
         if (xform.MapUid != null && xform.MapUid != uid)
             _transform.SetParent(uid, xform, xform.MapUid.Value);
 
-        if (!HasComp<MapComponent>(uid))
+        if (!_mapQuery.HasComponent(uid))
         {
             var aabb = GetWorldAABB(uid, component);
 
@@ -506,7 +506,7 @@ public abstract partial class SharedMapSystem
 
     private void AddGrid(EntityUid uid, MapGridComponent grid)
     {
-        DebugTools.Assert(!EntityManager.HasComponent<MapComponent>(uid));
+        DebugTools.Assert(!_mapQuery.HasComponent(uid));
         var aabb = GetWorldAABB(uid, grid);
 
         if (!_xformQuery.TryGetComponent(uid, out var xform))
@@ -1254,7 +1254,7 @@ public abstract partial class SharedMapSystem
                 $"Grid {uid} is on map {mapId}, but coords are on map {posWorld.MapId}.",
                 nameof(posWorld));
 
-        if (!TryComp<MapGridComponent>(uid, out var grid))
+        if (!_gridQuery.TryGetComponent(uid, out var grid))
         {
             return new EntityCoordinates(MapManager.GetMapEntityId(posWorld.MapId), new Vector2(posWorld.X, posWorld.Y));
         }

Robust.Shared/GameObjects/Systems/SharedMapSystem.cs

@@ -21,12 +21,16 @@ namespace Robust.Shared.GameObjects
         [Dependency] private readonly SharedPhysicsSystem _physics = default!;
         [Dependency] private readonly SharedTransformSystem _transform = default!;
 
+        private EntityQuery<MapComponent> _mapQuery;
+        private EntityQuery<MapGridComponent> _gridQuery;
         private EntityQuery<TransformComponent> _xformQuery;
 
         public override void Initialize()
         {
             base.Initialize();
 
+            _mapQuery = GetEntityQuery<MapComponent>();
+            _gridQuery = GetEntityQuery<MapGridComponent>();
             _xformQuery = GetEntityQuery<TransformComponent>();
 
             InitializeMap();

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

@@ -0,0 +1,84 @@
+using System;
+using System.Numerics;
+using Robust.Shared.Map;
+
+namespace Robust.Shared.GameObjects;
+
+public abstract partial class SharedTransformSystem
+{
+    /*
+     * Helper methods for working with EntityCoordinates / MapCoordinates.
+     * For grid methods see SharedMapSystem.Coordinates
+     */
+
+    /// <summary>
+    ///     Verifies that this set of coordinates can be currently resolved to a location.
+    /// </summary>
+    /// <returns><see langword="true" /> if this set of coordinates can be currently resolved to a location, otherwise <see langword="false" />.</returns>
+    public bool IsValid(EntityCoordinates coordinates)
+    {
+        var entity = coordinates.EntityId;
+
+        if (!entity.IsValid() || !Exists(entity))
+            return false;
+
+        if (!float.IsFinite(coordinates.Position.X) || !float.IsFinite(coordinates.Position.Y))
+            return false;
+
+        return true;
+    }
+
+    /// <summary>
+    ///     Returns a new set of EntityCoordinates local to a new entity.
+    /// </summary>
+    /// <param name="entity">The entity that the new coordinates will be local to</param>
+    /// <returns>A new set of EntityCoordinates local to a new entity.</returns>
+    public EntityCoordinates WithEntityId(EntityCoordinates coordinates, EntityUid entity)
+    {
+        var mapPos = ToMapCoordinates(coordinates);
+
+        // You'd think this would throw like ToCoordinates does but TODO check that.
+        if (mapPos.MapId == MapId.Nullspace)
+        {
+            return new EntityCoordinates(entity, Vector2.Zero);
+        }
+
+        var xform = XformQuery.GetComponent(entity);
+
+        if (xform.MapID != mapPos.MapId)
+        {
+            return new EntityCoordinates(entity, Vector2.Zero);
+        }
+
+        var localPos = GetInvWorldMatrix(xform).Transform(mapPos.Position);
+        return new EntityCoordinates(entity, localPos);
+    }
+
+    /// <summary>
+    /// Converts entity-local coordinates into map terms.
+    /// </summary>
+    public MapCoordinates ToMapCoordinates(EntityCoordinates coordinates)
+    {
+        if (!IsValid(coordinates))
+            return MapCoordinates.Nullspace;
+
+        var xform = XformQuery.GetComponent(coordinates.EntityId);
+        var worldPos = GetWorldMatrix(xform).Transform(coordinates.Position);
+        return new MapCoordinates(worldPos, xform.MapID);
+    }
+
+    /// <summary>
+    ///    Creates EntityCoordinates given an entity and some MapCoordinates.
+    /// </summary>
+    /// <exception cref="InvalidOperationException">If <see cref="entity"/> is not on the same map as the <see cref="coordinates"/>.</exception>
+    public EntityCoordinates ToCoordinates(EntityUid entity, MapCoordinates coordinates)
+    {
+        var xform = XformQuery.GetComponent(entity);
+
+        if (xform.MapID != coordinates.MapId)
+            throw new InvalidOperationException("Entity is not on the same map!");
+
+        var localPos = GetInvWorldMatrix(xform).Transform(coordinates.Position);
+        return new EntityCoordinates(entity, localPos);
+    }
+}

Robust.Shared/Map/CoordinatesExtensions.cs

@@ -1,6 +1,4 @@
-using System;
 using System.Collections.Generic;
-using System.Numerics;
 using Robust.Shared.GameObjects;
 using Robust.Shared.IoC;
 using Robust.Shared.Map.Components;
@@ -10,16 +8,6 @@ namespace Robust.Shared.Map
 {
     public static class CoordinatesExtensions
     {
-        public static EntityCoordinates ToEntityCoordinates(this Vector2i vector, EntityUid gridId, IMapManager? mapManager = null)
-        {
-            IoCManager.Resolve(ref mapManager);
-
-            var grid = mapManager.GetGrid(gridId);
-            var tile = grid.TileSize;
-
-            return new EntityCoordinates(gridId, new Vector2(vector.X * tile, vector.Y * tile));
-        }
-
         public static EntityCoordinates AlignWithClosestGridTile(this EntityCoordinates coords, float searchBoxSize = 1.5f, IEntityManager? entityManager = null, IMapManager? mapManager = null)
         {
             IoCManager.Resolve(ref entityManager, ref mapManager);

Robust.Shared/Physics/Dynamics/Joints/Joint.cs

@@ -185,6 +185,21 @@ public abstract partial class Joint : IEquatable<Joint>
     // serializer.DataField(this, x => x.BodyA, "bodyA", EntityUid.Invalid);
     // serializer.DataField(this, x => x.BodyB, "bodyB", Ent);
 
+    /// <summary>
+    /// Gets the other entity on this joint or throws if it's not related.
+    /// </summary>
+    public EntityUid GetOther(EntityUid uid)
+    {
+        if (BodyAUid == uid)
+            return BodyBUid;
+
+        if (BodyBUid == uid)
+            return BodyAUid;
+
+        // Should return EntityUid.Invalid but larger joints refactor first so we can actually log it properly here.
+        throw new ArgumentOutOfRangeException($"EntityUid {uid} unrelated to joint");
+    }
+
     protected internal void Dirty(IEntityManager? entMan = null)
     {
         // TODO: move dirty & setter functions to a system.

Robust.Shared/Physics/Systems/SharedBroadphaseSystem.cs

@@ -67,14 +67,7 @@ namespace Robust.Shared.Physics.Systems
             UpdatesOutsidePrediction = true;
             UpdatesAfter.Add(typeof(SharedTransformSystem));
 
-            _cfg.OnValueChanged(CVars.BroadphaseExpand, SetBroadphaseExpand, true);
-        }
-
-        public override void Shutdown()
-        {
-            base.Shutdown();
-
-            _cfg.UnsubValueChanged(CVars.BroadphaseExpand, SetBroadphaseExpand);
+            Subs.CVar(_cfg, CVars.BroadphaseExpand, SetBroadphaseExpand, true);
         }
 
         private void SetBroadphaseExpand(float value) => _broadphaseExpand = value;

Robust.Shared/Physics/Systems/SharedJointSystem.Relay.cs

@@ -70,6 +70,18 @@ public abstract partial class SharedJointSystem
         if (_container.TryGetOuterContainer(uid, Transform(uid), out var container))
         {
             relay = container.Owner;
+
+            // Validate that the relay target is not being set to our own container.
+            foreach (var joint in component.Joints.Values)
+            {
+                var other = joint.GetOther(uid);
+
+                if (other == relay)
+                {
+                    SetRelay(uid, null, component);
+                    return;
+                }
+            }
         }
 
         SetRelay(uid, relay, component);

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

@@ -199,38 +199,20 @@ public abstract partial class SharedPhysicsSystem
 
     private void InitializeIsland()
     {
-        _configManager.OnValueChanged(CVars.NetTickrate, SetTickRate, true);
-        _configManager.OnValueChanged(CVars.WarmStarting, SetWarmStarting, true);
-        _configManager.OnValueChanged(CVars.MaxLinearCorrection, SetMaxLinearCorrection, true);
-        _configManager.OnValueChanged(CVars.MaxAngularCorrection, SetMaxAngularCorrection, true);
-        _configManager.OnValueChanged(CVars.VelocityIterations, SetVelocityIterations, true);
-        _configManager.OnValueChanged(CVars.PositionIterations, SetPositionIterations, true);
-        _configManager.OnValueChanged(CVars.MaxLinVelocity, SetMaxLinearVelocity, true);
-        _configManager.OnValueChanged(CVars.MaxAngVelocity, SetMaxAngularVelocity, true);
-        _configManager.OnValueChanged(CVars.SleepAllowed, SetSleepAllowed, true);
-        _configManager.OnValueChanged(CVars.AngularSleepTolerance, SetAngularToleranceSqr, true);
-        _configManager.OnValueChanged(CVars.LinearSleepTolerance, SetLinearToleranceSqr, true);
-        _configManager.OnValueChanged(CVars.TimeToSleep, SetTimeToSleep, true);
-        _configManager.OnValueChanged(CVars.VelocityThreshold, SetVelocityThreshold, true);
-        _configManager.OnValueChanged(CVars.Baumgarte, SetBaumgarte, true);
-    }
-
-    private void ShutdownIsland()
-    {
-        _configManager.UnsubValueChanged(CVars.NetTickrate, SetTickRate);
-        _configManager.UnsubValueChanged(CVars.WarmStarting, SetWarmStarting);
-        _configManager.UnsubValueChanged(CVars.MaxLinearCorrection, SetMaxLinearCorrection);
-        _configManager.UnsubValueChanged(CVars.MaxAngularCorrection, SetMaxAngularCorrection);
-        _configManager.UnsubValueChanged(CVars.VelocityIterations, SetVelocityIterations);
-        _configManager.UnsubValueChanged(CVars.PositionIterations, SetPositionIterations);
-        _configManager.UnsubValueChanged(CVars.MaxLinVelocity, SetMaxLinearVelocity);
-        _configManager.UnsubValueChanged(CVars.MaxAngVelocity, SetMaxAngularVelocity);
-        _configManager.UnsubValueChanged(CVars.SleepAllowed, SetSleepAllowed);
-        _configManager.UnsubValueChanged(CVars.AngularSleepTolerance, SetAngularToleranceSqr);
-        _configManager.UnsubValueChanged(CVars.LinearSleepTolerance, SetLinearToleranceSqr);
-        _configManager.UnsubValueChanged(CVars.TimeToSleep, SetTimeToSleep);
-        _configManager.UnsubValueChanged(CVars.VelocityThreshold, SetVelocityThreshold);
-        _configManager.UnsubValueChanged(CVars.Baumgarte, SetBaumgarte);
+        Subs.CVar(_configManager, CVars.NetTickrate, SetTickRate, true);
+        Subs.CVar(_configManager, CVars.WarmStarting, SetWarmStarting, true);
+        Subs.CVar(_configManager, CVars.MaxLinearCorrection, SetMaxLinearCorrection, true);
+        Subs.CVar(_configManager, CVars.MaxAngularCorrection, SetMaxAngularCorrection, true);
+        Subs.CVar(_configManager, CVars.VelocityIterations, SetVelocityIterations, true);
+        Subs.CVar(_configManager, CVars.PositionIterations, SetPositionIterations, true);
+        Subs.CVar(_configManager, CVars.MaxLinVelocity, SetMaxLinearVelocity, true);
+        Subs.CVar(_configManager, CVars.MaxAngVelocity, SetMaxAngularVelocity, true);
+        Subs.CVar(_configManager, CVars.SleepAllowed, SetSleepAllowed, true);
+        Subs.CVar(_configManager, CVars.AngularSleepTolerance, SetAngularToleranceSqr, true);
+        Subs.CVar(_configManager, CVars.LinearSleepTolerance, SetLinearToleranceSqr, true);
+        Subs.CVar(_configManager, CVars.TimeToSleep, SetTimeToSleep, true);
+        Subs.CVar(_configManager, CVars.VelocityThreshold, SetVelocityThreshold, true);
+        Subs.CVar(_configManager, CVars.Baumgarte, SetBaumgarte, true);
     }
 
     private void SetWarmStarting(bool value) => _warmStarting = value;

Robust.Shared/Physics/Systems/SharedPhysicsSystem.cs

@@ -92,9 +92,9 @@ namespace Robust.Shared.Physics.Systems
             InitializeIsland();
             InitializeContacts();
 
-            _configManager.OnValueChanged(CVars.AutoClearForces, OnAutoClearChange);
-            _configManager.OnValueChanged(CVars.NetTickrate, UpdateSubsteps, true);
-            _configManager.OnValueChanged(CVars.TargetMinimumTickrate, UpdateSubsteps, true);
+            Subs.CVar(_configManager, CVars.AutoClearForces, OnAutoClearChange);
+            Subs.CVar(_configManager, CVars.NetTickrate, UpdateSubsteps, true);
+            Subs.CVar(_configManager, CVars.TargetMinimumTickrate, UpdateSubsteps, true);
         }
 
         private void OnPhysicsShutdown(EntityUid uid, PhysicsComponent component, ComponentShutdown args)
@@ -250,8 +250,6 @@ namespace Robust.Shared.Physics.Systems
             base.Shutdown();
 
             ShutdownContacts();
-            ShutdownIsland();
-            _configManager.UnsubValueChanged(CVars.AutoClearForces, OnAutoClearChange);
         }
 
         private void UpdateMapAwakeState(EntityUid uid, PhysicsComponent body)

Robust.Shared/Replays/SharedReplayRecordingManager.cs

@@ -34,6 +34,11 @@ internal abstract partial class SharedReplayRecordingManager : IReplayRecordingM
     // date format for default replay names. Like the sortable template, but without colons.
     public const string DefaultReplayNameFormat = "yyyy-MM-dd_HH-mm-ss";
 
+    // Kinda arbitrary but (after multiplying by 1024 cuz it's kB)
+    // needs to be less than (max array size) / 2.
+    // I don't think anybody's gonna write 256 MB of chunk at once yeah?
+    private const int MaxTickBatchSize = 256 * 1024;
+
     [Dependency] protected readonly IGameTiming Timing = default!;
     [Dependency] protected readonly INetConfigurationManager NetConf = default!;
     [Dependency] private readonly IComponentFactory _factory = default!;
@@ -50,8 +55,8 @@ internal abstract partial class SharedReplayRecordingManager : IReplayRecordingM
     private List<object> _queuedMessages = new();
 
     // Config variables.
-    private int _maxCompressedSize;
-    private int _maxUncompressedSize;
+    private long _maxCompressedSize;
+    private long _maxUncompressedSize;
     private int _tickBatchSize;
     private bool _enabled;
 
@@ -63,9 +68,9 @@ internal abstract partial class SharedReplayRecordingManager : IReplayRecordingM
     {
         _sawmill = _logManager.GetSawmill("replay");
 
-        NetConf.OnValueChanged(CVars.ReplayMaxCompressedSize, (v) => _maxCompressedSize = v * 1024, true);
-        NetConf.OnValueChanged(CVars.ReplayMaxUncompressedSize, (v) => _maxUncompressedSize = v * 1024, true);
-        NetConf.OnValueChanged(CVars.ReplayTickBatchSize, (v) => _tickBatchSize = v * 1024, true);
+        NetConf.OnValueChanged(CVars.ReplayMaxCompressedSize, (v) => _maxCompressedSize = SaturatingMultiplyKb(v), true);
+        NetConf.OnValueChanged(CVars.ReplayMaxUncompressedSize, (v) => _maxUncompressedSize = SaturatingMultiplyKb(v), true);
+        NetConf.OnValueChanged(CVars.ReplayTickBatchSize, (v) => _tickBatchSize = Math.Min(v, MaxTickBatchSize) * 1024, true);
         NetConf.OnValueChanged(CVars.NetPvsCompressLevel, OnCompressionChanged);
     }
 
@@ -450,6 +455,18 @@ internal abstract partial class SharedReplayRecordingManager : IReplayRecordingM
         return new ReplayRecordingStats(time, tick, size, altSize);
     }
 
+    private static long SaturatingMultiplyKb(long kb)
+    {
+        var result = kb * 1024;
+        if (result < kb)
+        {
+            // Overflow
+            return long.MaxValue;
+        }
+
+        return result;
+    }
+
     /// <summary>
     /// Contains all state related to an active recording.
     /// </summary>

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

@@ -0,0 +1,65 @@
+using System;
+using System.Globalization;
+using JetBrains.Annotations;
+using Robust.Shared.IoC;
+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;
+
+namespace Robust.Shared.Serialization.TypeSerializers.Implementations;
+
+/// <summary>
+/// Implements serialization for <see cref="DateTime"/>.
+/// </summary>
+/// <remarks>
+/// Serialization is implemented with <see cref="DateTimeStyles.RoundtripKind"/> and the "o" format specifier.
+/// </remarks>
+[TypeSerializer]
+public sealed class DateTimeSerializer : ITypeSerializer<DateTime, ValueDataNode>, ITypeCopyCreator<DateTime>
+{
+    public ValidationNode Validate(
+        ISerializationManager serializationManager,
+        ValueDataNode node,
+        IDependencyCollection dependencies,
+        ISerializationContext? context = null)
+    {
+        return DateTime.TryParse(node.Value, null, DateTimeStyles.RoundtripKind, out _)
+            ? new ValidatedValueNode(node)
+            : new ErrorNode(node, "Failed parsing DateTime");
+    }
+
+    public DateTime Read(
+        ISerializationManager serializationManager,
+        ValueDataNode node,
+        IDependencyCollection dependencies,
+        SerializationHookContext hookCtx,
+        ISerializationContext? context = null,
+        ISerializationManager.InstantiationDelegate<DateTime>? instanceProvider = null)
+    {
+        return DateTime.Parse(node.Value, null, DateTimeStyles.RoundtripKind);
+    }
+
+    public DataNode Write(
+        ISerializationManager serializationManager,
+        DateTime value,
+        IDependencyCollection dependencies,
+        bool alwaysWrite = false,
+        ISerializationContext? context = null)
+    {
+        return new ValueDataNode(value.ToString("o"));
+    }
+
+    [MustUseReturnValue]
+    public DateTime CreateCopy(
+        ISerializationManager serializationManager,
+        DateTime source,
+        IDependencyCollection dependencies,
+        SerializationHookContext hookCtx,
+        ISerializationContext? context = null)
+    {
+        return source;
+    }
+}

Robust.UnitTesting/RobustIntegrationTest.cs

@@ -759,8 +759,9 @@ namespace Robust.UnitTesting
 
         public sealed class ClientIntegrationInstance : IntegrationInstance
         {
+            [Obsolete("Use Session instead")]
             public LocalPlayer? Player => ((IPlayerManager) PlayerMan).LocalPlayer;
-            public ICommonSession? Session => Player?.Session;
+            public ICommonSession? Session => ((IPlayerManager) PlayerMan).LocalSession;
             public NetUserId? User => Session?.UserId;
             public EntityUid? AttachedEntity => Session?.AttachedEntity;
 

Robust.UnitTesting/Shared/GameState/NoSharedReferencesTest.cs

@@ -0,0 +1,115 @@
+using System;
+using NUnit.Framework;
+using Robust.Client.GameStates;
+using Robust.Shared.GameObjects;
+using Robust.Shared.GameStates;
+using Robust.Shared.Network;
+using Robust.Shared.Serialization;
+using System.Linq;
+using System.Threading.Tasks;
+using static Robust.UnitTesting.Shared.GameState.ExampleAutogeneratedComponent;
+
+namespace Robust.UnitTesting.Shared.GameState;
+
+/// <summary>
+/// This is a test of test engine <see cref="RobustIntegrationTest"/>. Not a test of game engine.
+/// </summary>
+public sealed partial class NoSharedReferencesTest : RobustIntegrationTest
+{
+    /// <summary>
+    /// The test performs a basic check to ensure that there is no issue with server's object references leaking to client.
+    /// It accomplishments this by testing two things: 1) That the reference object on both sides is not the same; and
+    /// 2) That the client-side copy of server's component state (used for prediction resetting) is not the same.
+    /// </summary>
+    [Test]
+    public async Task ReferencesAreNotShared()
+    {
+        var serverOpts = new ServerIntegrationOptions { Pool = false };
+        var clientOpts = new ClientIntegrationOptions { Pool = false };
+        var server = StartServer(serverOpts);
+        var client = StartClient(clientOpts);
+
+        await Task.WhenAll(client.WaitIdleAsync(), server.WaitIdleAsync());
+        var netMan = client.ResolveDependency<IClientNetManager>();
+        var clientGameStateManager = client.ResolveDependency<IClientGameStateManager>();
+
+        Assert.DoesNotThrow(() => client.SetConnectTarget(server));
+        client.Post(() => netMan.ClientConnect(null!, 0, null!));
+
+        // Set up map.
+        EntityUid map = default;
+        await server.WaitPost(() =>
+        {
+            var mapId = server.MapMan.CreateMap();
+            map = server.MapMan.GetMapEntityId(mapId);
+        });
+
+        await RunTicks();
+
+        EntityUid sPlayer = default;
+        EntityUid cPlayer = default;
+        ExampleObject serverObject = default!;
+        var sEntMan = server.EntMan;
+
+        // Set up test entity (player).
+        await server.WaitPost(() =>
+        {
+            sPlayer = sEntMan.Spawn();
+            serverObject = new ExampleObject(5);
+
+            var comp = new ExampleAutogeneratedComponent { ReferenceObject = serverObject };
+            sEntMan.AddComponent(sPlayer, comp);
+
+            var session = server.PlayerMan.Sessions.First();
+            server.PlayerMan.SetAttachedEntity(session, sPlayer);
+            server.PlayerMan.JoinGame(session);
+        });
+
+        // Let Client sync state with Server
+        await RunTicks();
+
+        // Assert that Client's object and client-side server state objects are different to Server's object
+        Assert.Multiple(() =>
+        {
+            // Player attached assertions
+            var cEntMan = client.EntMan;
+            cPlayer = cEntMan.GetEntity(server.EntMan.GetNetEntity(sPlayer));
+            Assert.That(client.AttachedEntity, Is.EqualTo(cPlayer));
+            Assert.That(cEntMan.EntityExists(cPlayer));
+
+            // Assert client and server have different objects of same values
+            Assert.That(cEntMan.TryGetComponent(cPlayer, out ExampleAutogeneratedComponent? comp));
+            var clientObject = comp?.ReferenceObject;
+            Assert.That(clientObject, Is.EqualTo(serverObject));
+            Assert.That(ReferenceEquals(clientObject, serverObject), Is.False);
+
+            // Assert that client-side dictionary of server component state also isn't contaminated by server references
+            var componentStates = clientGameStateManager.GetFullRep()[cEntMan.GetNetEntity(cPlayer)];
+            var clientLastTickStateObject = ((ExampleAutogeneratedComponent_AutoState)componentStates.First(x => x.Value is ExampleAutogeneratedComponent_AutoState).Value).ReferenceObject;
+            Assert.That(clientLastTickStateObject, Is.Not.Null);
+            Assert.That(ReferenceEquals(clientLastTickStateObject, serverObject), Is.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]
+public sealed partial class ExampleAutogeneratedComponent : Component
+{
+    [AutoNetworkedField]
+    public ExampleObject ReferenceObject;
+
+    [Serializable, NetSerializable]
+    public sealed record ExampleObject(int Value);
+}

Robust.UnitTesting/Shared/Networking/DisconnectTest.cs

@@ -73,8 +73,8 @@ public sealed class DisconnectTest : RobustIntegrationTest
 
             session = sPlayerMan.Sessions.Single();
             Assert.That(session.Status, Is.EqualTo(SessionStatus.Connected));
-            Assert.That(session.UserId, Is.EqualTo(cPlayerMan!.LocalPlayer?.UserId));
-            Assert.That(cPlayerMan.LocalPlayer, Is.Not.Null);
+            Assert.That(session.UserId, Is.EqualTo(cPlayerMan.LocalUser));
+            Assert.That(cPlayerMan.LocalSession, Is.Not.Null);
         }
 
         void AssertDisconnected()

Robust.UnitTesting/Shared/Serialization/TypeSerializers/DateTimeSerializerTest.cs

@@ -0,0 +1,31 @@
+using System;
+using System.Globalization;
+using NUnit.Framework;
+using Robust.Shared.Serialization.Manager;
+using Robust.Shared.Serialization.Markdown.Value;
+using Robust.Shared.Serialization.TypeSerializers.Implementations;
+
+namespace Robust.UnitTesting.Shared.Serialization.TypeSerializers;
+
+[TestFixture]
+[TestOf(typeof(DateTimeSerializer))]
+internal sealed class DateTimeSerializerTest : SerializationTest
+{
+    [Test]
+    public void WriteTest()
+    {
+        var dateTime = DateTime.UtcNow;
+        var result = Serialization.WriteValueAs<ValueDataNode>(dateTime);
+
+        var parsed = DateTime.Parse(result.Value, null, DateTimeStyles.RoundtripKind);
+        Assert.That(parsed, Is.EqualTo(dateTime));
+    }
+
+    [Test]
+    public void ReadTest()
+    {
+        var result = Serialization.Read<DateTime>(new ValueDataNode("2020-07-10 15:00:00.000"));
+
+        Assert.That(result, Is.EqualTo(new DateTime(2020, 07, 10, 15, 0, 0)));
+    }
+}