Allow lua API to bind a minimal set of properties to dead actors.

OpenRA.Game/Scripting/ScriptActorInterface.cs

@@ -9,6 +9,7 @@
 #endregion
 
 using System;
+using System.Collections.Generic;
 using System.Linq;
 
 namespace OpenRA.Scripting
@@ -18,15 +19,33 @@ namespace OpenRA.Scripting
 		readonly Actor actor;
 
 		protected override string DuplicateKeyError(string memberName) { return "Actor '{0}' defines the command '{1}' on multiple traits".F(actor.Info.Name, memberName); }
-		protected override string MemberNotFoundError(string memberName) { return "Actor '{0}' does not define a property '{1}'".F(actor.Info.Name, memberName); }
+		protected override string MemberNotFoundError(string memberName)
+		{
+			var actorName = actor.Info.Name;
+			if (actor.IsDead())
+				actorName += " (dead)";
+
+			return "Actor '{0}' does not define a property '{1}'".F(actorName, memberName);
+		}
 
 		public ScriptActorInterface(ScriptContext context, Actor actor)
 			: base(context)
 		{
 			this.actor = actor;
 
+			InitializeBindings();
+		}
+
+		void InitializeBindings()
+		{
+			var commandClasses = context.ActorCommands[actor.Info].AsEnumerable();
+
+			// Destroyed actors cannot have their traits queried
+			if (actor.Destroyed)
+				commandClasses = commandClasses.Where(c => c.HasAttribute<ExposedForDestroyedActors>());
+
 			var args = new object[] { context, actor };
-			var objects = context.ActorCommands[actor.Info].Select(cg =>
+			var objects = commandClasses.Select(cg =>
 			{
 				var groupCtor = cg.GetConstructor(new Type[] { typeof(ScriptContext), typeof(Actor) });
 				return groupCtor.Invoke(args);
@@ -34,5 +53,11 @@ namespace OpenRA.Scripting
 
 			Bind(objects);
 		}
+
+		public void OnActorDestroyed()
+		{
+			// Regenerate bindings to remove access to bogus trait state
+			InitializeBindings();
+		}
 	}
 }

OpenRA.Game/Scripting/ScriptContext.cs

@@ -39,6 +39,9 @@ namespace OpenRA.Scripting
 		public ScriptPropertyGroupAttribute(string category) { Category = category; }
 	}
 
+	// For property groups that are safe to initialize invoke on destroyed actors
+	public sealed class ExposedForDestroyedActors : Attribute { }
+
 	public sealed class ScriptActorPropertyActivityAttribute : Attribute { }
 
 	public abstract class ScriptActorProperties