Trve Assembly hot-reloading

Robust.Client/ClientIoC.cs

@@ -3,6 +3,7 @@
 using Robust.Client.Audio.Midi;
 using Robust.Client.Configuration;
 using Robust.Client.Console;
+using Robust.Client.ContentPack;
 using Robust.Client.Debugging;
 using Robust.Client.GameObjects;
 using Robust.Client.GameStates;
@@ -174,6 +175,7 @@ public static void RegisterIoC(GameController.DisplayMode mode, IDependencyColle
             deps.Register<IXamlProxyHelper, XamlProxyHelper>();
             deps.Register<MarkupTagManager>();
             deps.Register<IHWId, BasicHWId>();
+            deps.Register<IHotReloadManager, ClientHotReloadManager>(); // DevaStation - hot-reload
         }
     }
 }

Robust.Client/ContentPack/ClientHotReloadManager.cs

@@ -0,0 +1,31 @@
+using Robust.Shared;
+using Robust.Shared.Configuration;
+using Robust.Shared.ContentPack;
+using Robust.Shared.IoC;
+using Robust.Shared.Network;
+using Robust.Shared.Network.Messages;
+
+namespace Robust.Client.ContentPack;
+
+internal sealed class ClientHotReloadManager : HotReloadManager
+{
+    [Dependency] private readonly INetManager _netManager = default!;
+    [Dependency] private readonly IConfigurationManager _cfg = default!;
+
+    public override void Initialize()
+    {
+        base.Initialize();
+
+        _netManager.RegisterNetMessage<MsgHotReload>(HandleHotReloadMessage);
+    }
+
+    private void HandleHotReloadMessage(MsgHotReload msg)
+    {
+        if (!_cfg.GetCVar(CVars.HotReload))
+        {
+            return;
+        }
+
+        TriggerReload(msg.AssemblyName);
+    }
+}

Robust.Client/GameController/GameController.cs

@@ -98,6 +98,7 @@ internal sealed partial class GameController : IGameControllerInternal
         [Dependency] private readonly ILocalizationManager _loc = default!;
         [Dependency] private readonly ISystemFontManagerInternal _systemFontManager = default!;
         [Dependency] private readonly LoadingScreenManager _loadscr = default!;
+        [Dependency] private readonly IHotReloadManager _hotReloadManager = default!; // DevaStation - hot-reload
 
         private IWebViewManagerHook? _webViewHook;
 
@@ -244,6 +245,9 @@ internal bool StartupContinue(DisplayMode displayMode)
 
             _loadscr.LoadingStep(() => _modLoader.BroadcastRunLevel(ModRunLevel.PostInit), "Content PostInit");
 
+            // DevaStation start - hot-reload
+            _hotReloadManager.Initialize();
+
             _loadscr.Finish();
 
             if (_commandLineArgs?.Username != null)
@@ -347,6 +351,11 @@ private bool LoadModules()
                 return false;
             }
 
+            // DevaStation start - hot-reload
+            _hotReloadManager.AssemblyDirectory = assemblyDir;
+            _hotReloadManager.FilterPrefix = assemblyPrefix;
+            // DevaStation end
+
             return true;
         }
 

Robust.Server/BaseServer.cs

@@ -107,6 +107,7 @@ internal sealed class BaseServer : IBaseServerInternal, IPostInjectInit
         [Dependency] private readonly UploadedContentManager _uploadedContMan = default!;
         [Dependency] private readonly NetworkResourceManager _netResMan = default!;
         [Dependency] private readonly IReflectionManager _refMan = default!;
+        [Dependency] private readonly IHotReloadManager _hotReloadManager = default!; // DevaStation - hot-reload
 
         private readonly Stopwatch _uptimeStopwatch = new();
 
@@ -326,6 +327,11 @@ public bool Start(ServerOptions options, Func<ILogHandler>? logHandlerFactory =
                 return true;
             }
 
+            // DevaStation start - hot-reload
+            _hotReloadManager.AssemblyDirectory = Options.AssemblyDirectory;
+            _hotReloadManager.FilterPrefix = resourceManifest.AssemblyPrefix ?? Options.ContentModulePrefix;
+            // DevaStation end
+
             foreach (var loadedModule in _modLoader.LoadedModules)
             {
                 _config.LoadCVarsFromAssembly(loadedModule);
@@ -411,6 +417,8 @@ public bool Start(ServerOptions options, Func<ILogHandler>? logHandlerFactory =
 
             _modLoader.BroadcastRunLevel(ModRunLevel.PostInit);
 
+            _hotReloadManager.Initialize(); // DevaStation - hot-reload
+
             _statusHost.Start();
             _hubManager.Start();
 

Robust.Server/ContentPack/ServerHotReloadManager.cs

@@ -0,0 +1,40 @@
+using Robust.Shared;
+using Robust.Shared.Configuration;
+using Robust.Shared.ContentPack;
+using Robust.Shared.IoC;
+using Robust.Shared.Network;
+using Robust.Shared.Network.Messages;
+
+namespace Robust.Server.ContentPack;
+
+internal sealed class ServerHotReloadManager : HotReloadManager
+{
+    [Dependency] private readonly INetManager _netManager = default!;
+    [Dependency] private readonly IConfigurationManager _cfg = default!;
+
+    private AssemblyFileWatcher? _fileWatcher;
+
+    public override void Initialize()
+    {
+        base.Initialize();
+
+        _netManager.RegisterNetMessage<MsgHotReload>();
+
+        if (!_cfg.GetCVar(CVars.HotReload))
+            return;
+
+        _fileWatcher = new AssemblyFileWatcher();
+        IoCManager.InjectDependencies(_fileWatcher);
+        _fileWatcher.Initialize(AssemblyDirectory, FilterPrefix, TriggerReloadForAssembly);
+    }
+
+    private void TriggerReloadForAssembly(string assemblyName)
+    {
+        if (!_cfg.GetCVar(CVars.HotReload))
+            return;
+
+        _netManager.ServerSendToAll(new MsgHotReload { AssemblyName = assemblyName });
+
+        TriggerReload(assemblyName);
+    }
+}

Robust.Server/GameObjects/ServerEntityManager.cs

@@ -271,7 +271,7 @@ private void OnPlayerStatusChanged(object? sender, SessionStatusEventArgs args)
             switch (args.NewStatus)
             {
                 case SessionStatus.Connected:
-                    _lastProcessedSequencesCmd.Add(args.Session, 0);
+                    _lastProcessedSequencesCmd[args.Session] = 0; // DevaStation - hot-reload: use indexing
                     break;
 
                 case SessionStatus.Disconnected:

Robust.Server/GameStates/PvsSystem.Dirty.cs

@@ -30,6 +30,10 @@ private void InitializeDirty()
                 _addEntities[i] = new HashSet<EntityUid>(32);
                 _dirtyEntities[i] = new HashSet<EntityUid>(32);
             }
+            // DevaStation start - hot-reload
+            // Sync _currentIndex to current tick so the assertion in OnEntityAdd holds after reinit
+            _currentIndex = (int)(_gameTiming.CurTick.Value % DirtyBufferSize);
+            // DevaStation end
             EntityManager.EntityAdded += OnEntityAdd;
             EntityManager.EntityDirtied += OnEntityDirty;
         }
@@ -42,6 +46,19 @@ private void ShutdownDirty()
 
         private void OnEntityAdd(Entity<MetaDataComponent> e)
         {
+            // DevaStation start - hot-reload
+            // Auto-correct _currentIndex when stale. CleanupDirty() only runs from
+            // AfterSerializeStates() which requires connected players, so after a
+            // hot-reload with no clients _currentIndex drifts from the actual tick.
+            var expectedIndex = (int)(_gameTiming.CurTick.Value % DirtyBufferSize);
+            if (_currentIndex != expectedIndex
+                && _gameTiming.GetType().Name != "IGameTimingProxy")
+            {
+                _currentIndex = expectedIndex;
+                _addEntities[_currentIndex].Clear();
+                _dirtyEntities[_currentIndex].Clear();
+            }
+            // DevaStation end
             DebugTools.Assert(_currentIndex == _gameTiming.CurTick.Value % DirtyBufferSize ||
                 _gameTiming.GetType().Name == "IGameTimingProxy");// Look I have NFI how best to excuse this assert if the game timing isn't real (a Mock<IGameTiming>).
             _addEntities[_currentIndex].Add(e);
@@ -55,6 +72,17 @@ private void OnEntityDirty(Entity<MetaDataComponent> uid)
                 meta.LastModifiedTick = uid.Comp.EntityLastModifiedTick;
             }
 
+            // DevaStation start - hot-reload
+            // OH MY STALE _currentIndex!
+            var expectedIndex = (int)(_gameTiming.CurTick.Value % DirtyBufferSize);
+            if (_currentIndex != expectedIndex)
+            {
+                _currentIndex = expectedIndex;
+                _addEntities[_currentIndex].Clear();
+                _dirtyEntities[_currentIndex].Clear();
+            }
+            // DevaStation end
+
             if (!_addEntities[_currentIndex].Contains(uid))
                 _dirtyEntities[_currentIndex].Add(uid);
         }

Robust.Server/ServerIoC.cs

@@ -1,6 +1,7 @@
 using System.Diagnostics.Metrics;
 using Robust.Server.Configuration;
 using Robust.Server.Console;
+using Robust.Server.ContentPack;
 using Robust.Server.DataMetrics;
 using Robust.Server.GameObjects;
 using Robust.Server.GameStates;
@@ -102,6 +103,7 @@ internal static void RegisterIoC(IDependencyCollection deps)
             deps.Register<IHWId, DummyHWId>();
             deps.Register<ILocalizationManager, ServerLocalizationManager>();
             deps.Register<ILocalizationManagerInternal, ServerLocalizationManager>();
+            deps.Register<IHotReloadManager, ServerHotReloadManager>(); // DevaStation - hot-reload
         }
     }
 }

Robust.Shared.Testing/TestingModLoader.cs

@@ -54,6 +54,13 @@ public void AddEngineModuleDirectory(string dir)
         {
             // Only used for ILVerify, not necessary.
         }
+        // DevaStation - hot-reload
+        public (Assembly oldAssembly, Assembly newAssembly)? ReloadSingleAssembly(string assemblyName, ResPath assemblyDirectory, string filterPrefix)
+        {
+            // nop
+            return null;
+        }
+
 #pragma warning disable CS0067 // Needed by interface
         public event ExtraModuleLoad? ExtraModuleLoaders;
 #pragma warning restore CS0067

Robust.Shared/CVars.cs

@@ -1525,6 +1525,16 @@ protected CVars()
         public static readonly CVarDef<int> DebugTargetFps =
             CVarDef.Create("debug.target_fps", 60, CVar.CLIENTONLY | CVar.ARCHIVE);
 
+        // DevaStation start
+        /// <summary>
+        /// Whether to enable assembly hot-reloading for content assemblies.
+        /// When enabled, content DLLs marked with [assembly: AssemblyMetadata("HotReloadable", "true")]
+        /// will be watched for changes and reloaded at runtime
+        /// </summary>
+        public static readonly CVarDef<bool> HotReload =
+            CVarDef.Create("devaStation.hot_reload", true);
+        // DevaStation end
+
         /*
          * MIDI
          */

Robust.Shared/Console/ConsoleHost.cs

@@ -70,10 +70,16 @@ public void LoadConsoleCommands()
                     continue;
 
                 var instance = (IConsoleCommand)_typeFactory.CreateInstanceUnchecked(type, true);
-                if (AvailableCommands.TryGetValue(instance.Command, out var duplicate))
+
+                // DevaStation start - hot-reload
+                if (AvailableCommands.TryGetValue(instance.Command, out var existing))
                 {
+                    // Allow re-registration of the same command type during hot-reload
+                    if (existing.GetType().FullName == instance.GetType().FullName)
+                        continue;
+
                     throw new InvalidImplementationException(instance.GetType(), typeof(IConsoleCommand),
-                        $"Command name already registered: {instance.Command}, previous: {duplicate.GetType()}");
+                        $"Command name already registered: {instance.Command}, previous: {existing.GetType()}");
                 }
 
                 RegisteredCommands[instance.Command] = instance;
@@ -110,9 +116,6 @@ public void RegisterCommand(
             ConCommandCallback callback,
             bool requireServerOrSingleplayer = false)
         {
-            if (RegisteredCommands.ContainsKey(command))
-                throw new InvalidOperationException($"Command already registered: {command}");
-
             var newCmd = new RegisteredCommand(command, description, help, callback, requireServerOrSingleplayer);
             RegisterCommand(newCmd);
         }
@@ -125,9 +128,6 @@ public void RegisterCommand(
             ConCommandCompletionCallback completionCallback,
             bool requireServerOrSingleplayer = false)
         {
-            if (RegisteredCommands.ContainsKey(command))
-                throw new InvalidOperationException($"Command already registered: {command}");
-
             var newCmd = new RegisteredCommand(command, description, help, callback, completionCallback, requireServerOrSingleplayer);
             RegisterCommand(newCmd);
         }
@@ -140,8 +140,6 @@ public void RegisterCommand(
             ConCommandCompletionAsyncCallback completionCallback,
             bool requireServerOrSingleplayer = false)
         {
-            if (RegisteredCommands.ContainsKey(command))
-                throw new InvalidOperationException($"Command already registered: {command}");
 
             var newCmd = new RegisteredCommand(command, description, help, callback, completionCallback, requireServerOrSingleplayer);
             RegisterCommand(newCmd);
@@ -179,14 +177,26 @@ public void RegisterCommand(
 
         public void RegisterCommand(IConsoleCommand command)
         {
-            RegisteredCommands.Add(command.Command, command);
+            // DevaStation start - hot-reload: use indexer for safe overwrite
+            RegisteredCommands[command.Command] = command;
+            // DevaStation end
 
             if (!_isInRegistrationRegion)
                 UpdateAvailableCommands();
         }
 
         #endregion
 
+        /// <summary>
+        /// Clears all registered commands and auto-registration tracking.
+        /// Used during hot-reload teardown to remove commands from unloaded content assemblies.
+        /// </summary>
+        public void ClearAllCommands()
+        {
+            RegisteredCommands.Clear();
+            _autoRegisteredCommands.Clear();
+        }
+
         /// <inheritdoc />
         public void UnregisterCommand(string command)
         {

Robust.Shared/Console/IConsoleHost.cs

@@ -295,6 +295,13 @@ void RegisterCommand(
         /// Removes all text from the local console.
         /// </summary>
         void ClearLocalConsole();
+
+        // DevaStation start - hot-reload
+        /// <summary>
+        /// Clears all registered commands and auto-registration tracking.
+        /// Used during hot-reload teardown to remove commands from unloaded content assemblies.
+        /// </summary>
+        void ClearAllCommands();
     }
 
     internal interface IConsoleHostInternal : IConsoleHost