Merge pull request #9977 from RoosterDragon/dispose-lua-values

Ensure LuaValues are disposed

OpenRA.Game/Scripting/ScriptContext.cs

@@ -64,7 +64,19 @@ namespace OpenRA.Scripting
 		}
 	}
 
-	// For global-level bindings
+	/// <summary>
+	/// Provides global bindings in Lua code.
+	/// </summary>
+	/// <remarks>
+	/// Instance methods and properties declared in derived classes will be made available in Lua. Use
+	/// <see cref="ScriptGlobalAttribute"/> on your derived class to specify the name exposed in Lua. It is recommended
+	/// to apply <see cref="DescAttribute"/> against each method or property to provide a description of what it does.
+	///
+	/// Any parameters to your method that are <see cref="LuaValue"/>s will be disposed automatically when your method
+	/// completes. If you need to return any of these values, or need them to live longer than your method, you must
+	/// use <see cref="LuaValue.CopyReference"/> to get your own copy of the value. Any copied values you return will
+	/// be disposed automatically, but you assume responsibility for disposing any other copies.
+	/// </remarks>
 	public abstract class ScriptGlobal : ScriptObjectWrapper
 	{
 		protected override string DuplicateKeyError(string memberName) { return "Table '{0}' defines multiple members '{1}'".F(Name, memberName); }
@@ -78,11 +90,27 @@ namespace OpenRA.Scripting
 			var type = this.GetType();
 			var names = type.GetCustomAttributes<ScriptGlobalAttribute>(true);
 			if (names.Length != 1)
-				throw new InvalidOperationException("[LuaGlobal] attribute not found for global table '{0}'".F(type));
+				throw new InvalidOperationException("[ScriptGlobal] attribute not found for global table '{0}'".F(type));
 
 			Name = names.First().Name;
 			Bind(new[] { this });
 		}
+
+		protected IEnumerable<T> FilteredObjects<T>(IEnumerable<T> objects, LuaFunction filter)
+		{
+			if (filter != null)
+			{
+				objects = objects.Where(a =>
+				{
+					using (var luaObject = a.ToLuaValue(Context))
+					using (var filterResult = filter.Call(luaObject))
+					using (var result = filterResult.First())
+						return result.ToBoolean();
+				});
+			}
+
+			return objects;
+		}
 	}
 
 	public sealed class ScriptGlobalAttribute : Attribute

OpenRA.Game/Scripting/ScriptMemberWrapper.cs

@@ -44,31 +44,54 @@ namespace OpenRA.Scripting
 
 		LuaValue Invoke(LuaVararg args)
 		{
-			if (!IsMethod)
+			object[] clrArgs = null;
-				throw new LuaException("Trying to invoke a ScriptMemberWrapper that isn't a method!");
+			try
-
-			var mi = (MethodInfo)Member;
-			var pi = mi.GetParameters();
-
-			var clrArgs = new object[pi.Length];
-			var argCount = args.Count;
-			for (var i = 0; i < pi.Length; i++)
 			{
-				if (i >= argCount)
+				if (!IsMethod)
-				{
+					throw new LuaException("Trying to invoke a ScriptMemberWrapper that isn't a method!");
-					if (!pi[i].IsOptional)
-						throw new LuaException("Argument '{0}' of '{1}' is not optional.".F(pi[i].LuaDocString(), Member.LuaDocString()));
 
-					clrArgs[i] = pi[i].DefaultValue;
+				var mi = (MethodInfo)Member;
-					continue;
+				var pi = mi.GetParameters();
+
+				clrArgs = new object[pi.Length];
+
+				var argCount = args.Count;
+				for (var i = 0; i < pi.Length; i++)
+				{
+					if (i >= argCount)
+					{
+						if (!pi[i].IsOptional)
+							throw new LuaException("Argument '{0}' of '{1}' is not optional.".F(pi[i].LuaDocString(), Member.LuaDocString()));
+
+						clrArgs[i] = pi[i].DefaultValue;
+						continue;
+					}
+
+					if (!args[i].TryGetClrValue(pi[i].ParameterType, out clrArgs[i]))
+						throw new LuaException("Unable to convert parameter {0} to {1}".F(i, pi[i].ParameterType.Name));
 				}
 
-				if (!args[i].TryGetClrValue(pi[i].ParameterType, out clrArgs[i]))
+				return mi.Invoke(Target, clrArgs).ToLuaValue(context);
-					throw new LuaException("Unable to convert parameter {0} to {1}".F(i, pi[i].ParameterType.Name));
 			}
+			finally
+			{
+				// Clean up all the Lua arguments that were given to us.
+				foreach (var arg in args)
+					arg.Dispose();
+				args.Dispose();
 
-			var ret = mi.Invoke(Target, clrArgs);
+				// If we created any arrays of LuaValues to pass around, we need to dispose those too.
-			return ret.ToLuaValue(context);
+				if (clrArgs != null)
+				{
+					foreach (var arg in clrArgs)
+					{
+						if (!(arg is LuaValue[]))
+							continue;
+						foreach (var value in (LuaValue[])arg)
+							value.Dispose();
+					}
+				}
+			}
 		}
 
 		public LuaValue Get(LuaRuntime runtime)
@@ -77,10 +100,7 @@ namespace OpenRA.Scripting
 				return runtime.CreateFunctionFromDelegate((Func<LuaVararg, LuaValue>)Invoke);
 
 			if (IsGetProperty)
-			{
+				return ((PropertyInfo)Member).GetValue(Target, null).ToLuaValue(context);
-				var pi = Member as PropertyInfo;
-				return pi.GetValue(Target, null).ToLuaValue(context);
-			}
 
 			throw new LuaException("The property '{0}' is write-only".F(Member.Name));
 		}
@@ -89,7 +109,7 @@ namespace OpenRA.Scripting
 		{
 			if (IsSetProperty)
 			{
-				var pi = Member as PropertyInfo;
+				var pi = (PropertyInfo)Member;
 				object clrValue;
 				if (!value.TryGetClrValue(pi.PropertyType, out clrValue))
 					throw new LuaException("Unable to convert '{0}' to Clr type '{1}'".F(value.WrappedClrType().Name, pi.PropertyType));

OpenRA.Game/Scripting/ScriptTypes.cs

@@ -107,13 +107,22 @@ namespace OpenRA.Scripting
 
 				foreach (var kv in table)
 				{
-					object element;
+					using (kv.Key)
-					if (innerType == typeof(LuaValue))
+					{
-						element = kv.Value;
+						object element;
-					else if (!kv.Value.TryGetClrValue(innerType, out element))
+						if (innerType == typeof(LuaValue))
-						throw new LuaException("Unable to convert table value of type {0} to type {1}".F(kv.Value.WrappedClrType(), innerType));
+							element = kv.Value;
+						else
+						{
+							var elementHasClrValue = kv.Value.TryGetClrValue(innerType, out element);
+							if (!elementHasClrValue || !(element is LuaValue))
+								kv.Value.Dispose();
+							if (!elementHasClrValue)
+								throw new LuaException("Unable to convert table value of type {0} to type {1}".F(kv.Value.WrappedClrType(), innerType));
+						}
 
-					array.SetValue(element, i++);
+						array.SetValue(element, i++);
+					}
 				}
 
 				clrObject = array;
@@ -159,11 +168,13 @@ namespace OpenRA.Scripting
 
 			if (obj is Array)
 			{
-				var array = obj as Array;
+				var array = (Array)obj;
 				var i = 1;
 				var table = context.CreateTable();
+
 				foreach (var x in array)
-					table.Add(i++, x.ToLuaValue(context));
+					using (LuaValue key = i++, value = x.ToLuaValue(context))
+						table.Add(key, value);
 
 				return table;
 			}

OpenRA.Mods.Common/Scripting/Global/ActorGlobal.cs

@@ -29,26 +29,30 @@ namespace OpenRA.Mods.Common.Scripting
 			// Convert table entries into ActorInits
 			foreach (var kv in initTable)
 			{
-				// Find the requested type
+				using (kv.Key)
-				var typeName = kv.Key.ToString();
+				using (kv.Value)
-				var initType = Game.ModData.ObjectCreator.FindType(typeName + "Init");
+				{
-				if (initType == null)
+					// Find the requested type
-					throw new LuaException("Unknown initializer type '{0}'".F(typeName));
+					var typeName = kv.Key.ToString();
+					var initType = Game.ModData.ObjectCreator.FindType(typeName + "Init");
+					if (initType == null)
+						throw new LuaException("Unknown initializer type '{0}'".F(typeName));
 
-				// Cast it up to an IActorInit<T>
+					// Cast it up to an IActorInit<T>
-				var genericType = initType.GetInterfaces()
+					var genericType = initType.GetInterfaces()
-					.First(x => x.IsGenericType && x.GetGenericTypeDefinition() == typeof(IActorInit<>));
+						.First(x => x.IsGenericType && x.GetGenericTypeDefinition() == typeof(IActorInit<>));
-				var innerType = genericType.GetGenericArguments().First();
+					var innerType = genericType.GetGenericArguments().First();
-				var valueType = innerType.IsEnum ? typeof(int) : innerType;
+					var valueType = innerType.IsEnum ? typeof(int) : innerType;
 
-				// Try and coerce the table value to the required type
+					// Try and coerce the table value to the required type
-				object value;
+					object value;
-				if (!kv.Value.TryGetClrValue(valueType, out value))
+					if (!kv.Value.TryGetClrValue(valueType, out value))
-					throw new LuaException("Invalid data type for '{0}' (expected '{1}')".F(typeName, valueType.Name));
+						throw new LuaException("Invalid data type for '{0}' (expected '{1}')".F(typeName, valueType.Name));
 
-				// Construct the ActorInit. Phew!
+					// Construct the ActorInit. Phew!
-				var test = initType.GetConstructor(new[] { innerType }).Invoke(new[] { value });
+					var test = initType.GetConstructor(new[] { innerType }).Invoke(new[] { value });
-				initDict.Add(test);
+					initDict.Add(test);
+				}
 			}
 
 			// The actor must be added to the world at the end of the tick

OpenRA.Mods.Common/Scripting/Global/MapGlobal.cs

@@ -8,7 +8,6 @@
  */
 #endregion
 
-using System;
 using System.Linq;
 using Eluant;
 using OpenRA.Mods.Common.Traits;
@@ -34,34 +33,14 @@ namespace OpenRA.Mods.Common.Scripting
 		public Actor[] ActorsInCircle(WPos location, WDist radius, LuaFunction filter = null)
 		{
 			var actors = Context.World.FindActorsInCircle(location, radius);
-
+			return FilteredObjects(actors, filter).ToArray();
-			if (filter != null)
-			{
-				actors = actors.Where(a =>
-				{
-					using (var f = filter.Call(a.ToLuaValue(Context)))
-						return f.First().ToBoolean();
-				});
-			}
-
-			return actors.ToArray();
 		}
 
 		[Desc("Returns a table of all actors within the requested rectangle, filtered using the specified function.")]
 		public Actor[] ActorsInBox(WPos topLeft, WPos bottomRight, LuaFunction filter = null)
 		{
 			var actors = Context.World.ActorMap.ActorsInBox(topLeft, bottomRight);
-
+			return FilteredObjects(actors, filter).ToArray();
-			if (filter != null)
-			{
-				actors = actors.Where(a =>
-				{
-					using (var f = filter.Call(a.ToLuaValue(Context)))
-						return f.First().ToBoolean();
-				});
-			}
-
-			return actors.ToArray();
 		}
 
 		[Desc("Returns the location of the top-left corner of the map (assuming zero terrain height).")]

OpenRA.Mods.Common/Scripting/Global/MediaGlobal.cs

@@ -53,7 +53,6 @@ namespace OpenRA.Mods.Common.Scripting
 			Game.Sound.Play(file);
 		}
 
-		Action onComplete;
 		[Desc("Play track defined in music.yaml or map.yaml, or keep track empty for playing a random song.")]
 		public void PlayMusic(string track = null, LuaFunction func = null)
 		{
@@ -65,8 +64,8 @@ namespace OpenRA.Mods.Common.Scripting
 
 			if (func != null)
 			{
-				var f = func.CopyReference() as LuaFunction;
+				var f = (LuaFunction)func.CopyReference();
-				onComplete = () =>
+				Action onComplete = () =>
 				{
 					try
 					{
@@ -113,13 +112,13 @@ namespace OpenRA.Mods.Common.Scripting
 			playlist.Stop();
 		}
 
-		Action onCompleteFullscreen;
 		[Desc("Play a VQA video fullscreen. File name has to include the file extension.")]
 		public void PlayMovieFullscreen(string movie, LuaFunction func = null)
 		{
+			Action onCompleteFullscreen;
 			if (func != null)
 			{
-				var f = func.CopyReference() as LuaFunction;
+				var f = (LuaFunction)func.CopyReference();
 				onCompleteFullscreen = () =>
 				{
 					try
@@ -139,15 +138,14 @@ namespace OpenRA.Mods.Common.Scripting
 			Media.PlayFMVFullscreen(world, movie, onCompleteFullscreen);
 		}
 
-		Action onLoadComplete;
-		Action onCompleteRadar;
 		[Desc("Play a VQA video in the radar window. File name has to include the file extension. " +
 			"Returns true on success, if the movie wasn't found the function returns false and the callback is executed.")]
 		public bool PlayMovieInRadar(string movie, LuaFunction playComplete = null)
 		{
+			Action onCompleteRadar;
 			if (playComplete != null)
 			{
-				var f = playComplete.CopyReference() as LuaFunction;
+				var f = (LuaFunction)playComplete.CopyReference();
 				onCompleteRadar = () =>
 				{
 					try
@@ -178,7 +176,7 @@ namespace OpenRA.Mods.Common.Scripting
 
 			AsyncLoader l = new AsyncLoader(Media.LoadVqa);
 			IAsyncResult ar = l.BeginInvoke(s, null, null);
-			onLoadComplete = () =>
+			Action onLoadComplete = () =>
 			{
 				Media.StopFMVInRadar();
 				world.AddFrameEndTask(_ => Media.PlayFMVInRadar(world, l.EndInvoke(ar), onCompleteRadar));

OpenRA.Mods.Common/Scripting/Global/PlayerGlobal.cs

@@ -28,12 +28,7 @@ namespace OpenRA.Mods.Common.Scripting
 		[Desc("Returns a table of players filtered by the specified function.")]
 		public Player[] GetPlayers(LuaFunction filter)
 		{
-			return Context.World.Players
+			return FilteredObjects(Context.World.Players, filter).ToArray();
-				.Where(p =>
-				{
-					using (var f = filter.Call(p.ToLuaValue(Context)))
-						return f.First().ToBoolean();
-				}).ToArray();
 		}
 	}
 }

OpenRA.Mods.Common/Scripting/Global/ReinforcementsGlobal.cs

@@ -71,7 +71,7 @@ namespace OpenRA.Mods.Common.Scripting
 			var actors = new List<Actor>();
 			for (var i = 0; i < actorTypes.Length; i++)
 			{
-				var af = actionFunc != null ? actionFunc.CopyReference() as LuaFunction : null;
+				var af = actionFunc != null ? (LuaFunction)actionFunc.CopyReference() : null;
 				var actor = CreateActor(owner, actorTypes[i], false, entryPath[0], entryPath.Length > 1 ? entryPath[1] : (CPos?)null);
 				actors.Add(actor);
 
@@ -86,8 +86,9 @@ namespace OpenRA.Mods.Common.Scripting
 					{
 						actor.QueueActivity(new CallFunc(() =>
 						{
-							af.Call(actor.ToLuaValue(Context));
+							using (af)
-							af.Dispose();
+							using (var a = actor.ToLuaValue(Context))
+								af.Call(a);
 						}));
 					}
 				};
@@ -128,11 +129,12 @@ namespace OpenRA.Mods.Common.Scripting
 
 			if (actionFunc != null)
 			{
-				var af = actionFunc.CopyReference() as LuaFunction;
+				var af = (LuaFunction)actionFunc.CopyReference();
 				transport.QueueActivity(new CallFunc(() =>
 				{
-					af.Call(transport.ToLuaValue(Context), passengers.ToArray().ToLuaValue(Context));
+					using (af)
-					af.Dispose();
+					using (LuaValue t = transport.ToLuaValue(Context), p = passengers.ToArray().ToLuaValue(Context))
+						af.Call(t, p);
 				}));
 			}
 			else
@@ -164,11 +166,12 @@ namespace OpenRA.Mods.Common.Scripting
 
 			if (exitFunc != null)
 			{
-				var ef = exitFunc.CopyReference() as LuaFunction;
+				var ef = (LuaFunction)exitFunc.CopyReference();
 				transport.QueueActivity(new CallFunc(() =>
 				{
-					ef.Call(transport.ToLuaValue(Context));
+					using (ef)
-					ef.Dispose();
+					using (var t = transport.ToLuaValue(Context))
+						ef.Call(t);
 				}));
 			}
 			else if (exitPath != null)
@@ -180,8 +183,16 @@ namespace OpenRA.Mods.Common.Scripting
 			}
 
 			var ret = Context.CreateTable();
-			ret.Add(1, transport.ToLuaValue(Context));
+			using (LuaValue
-			ret.Add(2, passengers.ToArray().ToLuaValue(Context));
+				tKey = 1,
+				tValue = transport.ToLuaValue(Context),
+				pKey = 2,
+				pValue = passengers.ToArray().ToLuaValue(Context))
+			{
+				ret.Add(tKey, tValue);
+				ret.Add(pKey, pValue);
+			}
+
 			return ret;
 		}
 	}

OpenRA.Mods.Common/Scripting/Global/TriggerGlobal.cs

@@ -34,8 +34,7 @@ namespace OpenRA.Mods.Common.Scripting
 		[Desc("Call a function after a specified delay. The callback function will be called as func().")]
 		public void AfterDelay(int delay, LuaFunction func)
 		{
-			var f = func.CopyReference() as LuaFunction;
+			var f = (LuaFunction)func.CopyReference();
-
 			Action doCall = () =>
 			{
 				try
@@ -78,17 +77,15 @@ namespace OpenRA.Mods.Common.Scripting
 		public void OnAllKilled(Actor[] actors, LuaFunction func)
 		{
 			var group = actors.ToList();
-			var copy = (LuaFunction)func.CopyReference();
+			var f = (LuaFunction)func.CopyReference();
 			Action<Actor> onMemberKilled = m =>
 			{
 				try
 				{
 					group.Remove(m);
 					if (!group.Any())
-					{
+						using (f)
-						copy.Call();
+							f.Call();
-						copy.Dispose();
-					}
 				}
 				catch (Exception e)
 				{
@@ -105,7 +102,7 @@ namespace OpenRA.Mods.Common.Scripting
 		public void OnAnyKilled(Actor[] actors, LuaFunction func)
 		{
 			var called = false;
-			var copy = (LuaFunction)func.CopyReference();
+			var f = (LuaFunction)func.CopyReference();
 			Action<Actor> onMemberKilled = m =>
 			{
 				try
@@ -113,10 +110,10 @@ namespace OpenRA.Mods.Common.Scripting
 					if (called)
 						return;
 
+					using (f)
 					using (var killed = m.ToLuaValue(Context))
-						copy.Call(killed).Dispose();
+						f.Call(killed).Dispose();
 
-					copy.Dispose();
 					called = true;
 				}
 				catch (Exception e)
@@ -191,7 +188,7 @@ namespace OpenRA.Mods.Common.Scripting
 		{
 			var group = actors.ToList();
 
-			var copy = (LuaFunction)func.CopyReference();
+			var f = (LuaFunction)func.CopyReference();
 			Action<Actor> onMemberRemoved = m =>
 			{
 				try
@@ -200,10 +197,8 @@ namespace OpenRA.Mods.Common.Scripting
 						return;
 
 					if (!group.Any())
-					{
+						using (f)
-						copy.Call().Dispose();
+							f.Call().Dispose();
-						copy.Dispose();
-					}
 				}
 				catch (Exception e)
 				{
@@ -228,7 +223,7 @@ namespace OpenRA.Mods.Common.Scripting
 		{
 			var called = false;
 
-			var copy = (LuaFunction)func.CopyReference();
+			var f = (LuaFunction)func.CopyReference();
 			Action<Actor> onKilledOrCaptured = m =>
 			{
 				try
@@ -236,8 +231,9 @@ namespace OpenRA.Mods.Common.Scripting
 					if (called)
 						return;
 
-					copy.Call().Dispose();
+					using (f)
-					copy.Dispose();
+						f.Call().Dispose();
+
 					called = true;
 				}
 				catch (Exception e)
@@ -256,7 +252,7 @@ namespace OpenRA.Mods.Common.Scripting
 		{
 			var group = actors.ToList();
 
-			var copy = (LuaFunction)func.CopyReference();
+			var f = (LuaFunction)func.CopyReference();
 			Action<Actor> onMemberKilledOrCaptured = m =>
 			{
 				try
@@ -265,10 +261,8 @@ namespace OpenRA.Mods.Common.Scripting
 						return;
 
 					if (!group.Any())
-					{
+						using (f)
-						copy.Call().Dispose();
+							f.Call().Dispose();
-						copy.Dispose();
-					}
 				}
 				catch (Exception e)
 				{
@@ -288,8 +282,9 @@ namespace OpenRA.Mods.Common.Scripting
 			"The callback function will be called as func(Actor a, int id).")]
 		public int OnEnteredFootprint(CPos[] cells, LuaFunction func)
 		{
-			var triggerId = 0;
+			// We can't easily dispose onEntry, so we'll have to rely on finalization for it.
 			var onEntry = (LuaFunction)func.CopyReference();
+			var triggerId = 0;
 			Action<Actor> invokeEntry = a =>
 			{
 				try
@@ -314,8 +309,9 @@ namespace OpenRA.Mods.Common.Scripting
 			"The callback function will be called as func(Actor a, int id).")]
 		public int OnExitedFootprint(CPos[] cells, LuaFunction func)
 		{
-			var triggerId = 0;
+			// We can't easily dispose onExit, so we'll have to rely on finalization for it.
 			var onExit = (LuaFunction)func.CopyReference();
+			var triggerId = 0;
 			Action<Actor> invokeExit = a =>
 			{
 				try
@@ -346,8 +342,9 @@ namespace OpenRA.Mods.Common.Scripting
 			"The callback function will be called as func(Actor a, int id).")]
 		public int OnEnteredProximityTrigger(WPos pos, WDist range, LuaFunction func)
 		{
-			var triggerId = 0;
+			// We can't easily dispose onEntry, so we'll have to rely on finalization for it.
 			var onEntry = (LuaFunction)func.CopyReference();
+			var triggerId = 0;
 			Action<Actor> invokeEntry = a =>
 			{
 				try
@@ -372,8 +369,9 @@ namespace OpenRA.Mods.Common.Scripting
 			"The callback function will be called as func(Actor a, int id).")]
 		public int OnExitedProximityTrigger(WPos pos, WDist range, LuaFunction func)
 		{
-			var triggerId = 0;
+			// We can't easily dispose onExit, so we'll have to rely on finalization for it.
 			var onExit = (LuaFunction)func.CopyReference();
+			var triggerId = 0;
 			Action<Actor> invokeExit = a =>
 			{
 				try

OpenRA.Mods.Common/Scripting/Global/UtilsGlobal.cs

@@ -33,14 +33,10 @@ namespace OpenRA.Mods.Common.Scripting
 		public bool Any(LuaValue[] collection, LuaFunction func)
 		{
 			foreach (var c in collection)
-			{
 				using (var ret = func.Call(c))
-				{
+				using (var result = ret.FirstOrDefault())
-					var result = ret.FirstOrDefault();
 					if (result != null && result.ToBoolean())
 						return true;
-				}
-			}
 
 			return false;
 		}
@@ -49,14 +45,10 @@ namespace OpenRA.Mods.Common.Scripting
 		public bool All(LuaValue[] collection, LuaFunction func)
 		{
 			foreach (var c in collection)
-			{
 				using (var ret = func.Call(c))
-				{
+				using (var result = ret.FirstOrDefault())
-					var result = ret.FirstOrDefault();
 					if (result == null || !result.ToBoolean())
 						return false;
-				}
-			}
 
 			return true;
 		}
@@ -64,7 +56,7 @@ namespace OpenRA.Mods.Common.Scripting
 		[Desc("Returns the first n values from a collection.")]
 		public LuaValue[] Take(int n, LuaValue[] source)
 		{
-			return source.Take(n).ToArray();
+			return source.Take(n).Select(v => v.CopyReference()).ToArray();
 		}
 
 		[Desc("Skips over the first numElements members of a table and return the rest.")]
@@ -73,7 +65,8 @@ namespace OpenRA.Mods.Common.Scripting
 			var t = Context.CreateTable();
 
 			for (var i = numElements; i <= table.Count; i++)
-				t.Add(t.Count + 1, table[i]);
+				using (LuaValue key = t.Count + 1, value = table[i])
+					t.Add(key, value);
 
 			return t;
 		}
@@ -81,7 +74,7 @@ namespace OpenRA.Mods.Common.Scripting
 		[Desc("Returns a random value from a collection.")]
 		public LuaValue Random(LuaValue[] collection)
 		{
-			return collection.Random(Context.World.SharedRandom);
+			return collection.Random(Context.World.SharedRandom).CopyReference();
 		}
 
 		[Desc("Expands the given footprint one step along the coordinate axes, and (if requested) diagonals.")]

OpenRA.Mods.RA/Scripting/Properties/ChronosphereProperties.cs

@@ -28,8 +28,13 @@ namespace OpenRA.Mods.RA.Scripting
 			{
 				Actor actor;
 				CPos cell;
-				if (!kv.Key.TryGetClrValue<Actor>(out actor) || !kv.Value.TryGetClrValue<CPos>(out cell))
+				using (kv.Key)
-					throw new LuaException("Chronoshift requires a table of Actor,CPos pairs. Received {0},{1}".F(kv.Key.WrappedClrType().Name, kv.Value.WrappedClrType().Name));
+				using (kv.Value)
+				{
+					if (!kv.Key.TryGetClrValue(out actor) || !kv.Value.TryGetClrValue(out cell))
+						throw new LuaException("Chronoshift requires a table of Actor,CPos pairs. Received {0},{1}".F(
+							kv.Key.WrappedClrType().Name, kv.Value.WrappedClrType().Name));
+				}
 
 				var cs = actor.TraitOrDefault<Chronoshiftable>();
 				if (cs != null && cs.CanChronoshiftTo(actor, cell))