Allow ActorInits to target a specific trait by matching the @ suffix.

OpenRA.Game/GameRules/ActorInfo.cs

@@ -23,6 +23,7 @@ namespace OpenRA
 	public class ActorInfo
 	{
 		public const string AbstractActorPrefix = "^";
+		public const char TraitInstanceSeparator = '@';
 
 		/// <summary>
 		/// The actor name can be anything, but the sprites used in the Render*: traits default to this one.
@@ -46,7 +47,7 @@ namespace OpenRA
 					{
 						// HACK: The linter does not want to crash when a trait doesn't exist but only print an error instead
 						// LoadTraitInfo will only return null to signal us to abort here if the linter is running
-						var trait = LoadTraitInfo(creator, t.Key.Split('@')[0], t.Value);
+						var trait = LoadTraitInfo(creator, t.Key, t.Value);
 						if (trait != null)
 							traits.Add(trait);
 					}
@@ -80,12 +81,16 @@ namespace OpenRA
 
 			// HACK: The linter does not want to crash when a trait doesn't exist but only print an error instead
 			// ObjectCreator will only return null to signal us to abort here if the linter is running
-			var info = creator.CreateObject<TraitInfo>(traitName + "Info");
+			var traitInstance = traitName.Split(TraitInstanceSeparator);
+			var info = creator.CreateObject<TraitInfo>(traitInstance[0] + "Info");
 			if (info == null)
 				return null;
 
 			try
 			{
+				if (traitInstance.Length > 1)
+					info.GetType().GetField("InstanceName").SetValue(info, traitInstance[1]);
+
 				FieldLoader.Load(info, my);
 			}
 			catch (FieldLoader.MissingFieldsException e)

OpenRA.Game/Map/ActorInitializer.cs

@@ -43,7 +43,17 @@ namespace OpenRA
 
 		public T GetOrDefault<T>(TraitInfo info) where T : ActorInit
 		{
-			return Dict.GetOrDefault<T>();
+			var inits = Dict.WithInterface<T>();
+
+			// Traits tagged with an instance name prefer inits with the same name.
+			// If a more specific init is not available, fall back to an unnamed init.
+			// If duplicate inits are defined, take the last to match standard yaml override expectations
+			if (info != null && !string.IsNullOrEmpty(info.InstanceName))
+				return inits.LastOrDefault(i => i.InstanceName == info.InstanceName) ??
+					inits.LastOrDefault(i => string.IsNullOrEmpty(i.InstanceName));
+
+			// Untagged traits will only use untagged inits
+			return inits.LastOrDefault(i => string.IsNullOrEmpty(i.InstanceName));
 		}
 
 		public T Get<T>(TraitInfo info) where T : ActorInit
@@ -81,6 +91,16 @@ namespace OpenRA
 	 */
 	public abstract class ActorInit
 	{
+		[FieldLoader.Ignore]
+		public readonly string InstanceName;
+
+		protected ActorInit(string instanceName)
+		{
+			InstanceName = instanceName;
+		}
+
+		protected ActorInit() { }
+
 		public abstract MiniYaml Save();
 	}
 
@@ -88,7 +108,8 @@ namespace OpenRA
 	{
 		protected readonly T value;
 
-		protected ValueActorInit(TraitInfo info, T value) { this.value = value; }
+		protected ValueActorInit(TraitInfo info, T value)
+			: base(info.InstanceName) { this.value = value; }
 
 		protected ValueActorInit(T value) { this.value = value; }
 

OpenRA.Game/Map/ActorReference.cs

@@ -47,14 +47,18 @@ namespace OpenRA
 
 		static ActorInit LoadInit(string initName, MiniYaml initYaml)
 		{
-			var type = Game.ModData.ObjectCreator.FindType(initName + "Init");
+			var initInstance = initName.Split(ActorInfo.TraitInstanceSeparator);
+			var type = Game.ModData.ObjectCreator.FindType(initInstance[0] + "Init");
 			if (type == null)
-				throw new InvalidDataException("Unknown initializer type '{0}Init'".F(initName));
+				throw new InvalidDataException("Unknown initializer type '{0}Init'".F(initInstance[0]));
 
 			var init = (ActorInit)FormatterServices.GetUninitializedObject(type);
+			if (initInstance.Length > 1)
+				type.GetField("InstanceName").SetValue(init, initInstance[1]);
+
 			var loader = type.GetMethod("Initialize", new[] { typeof(MiniYaml) });
 			if (loader == null)
-				throw new InvalidDataException("{0}Init does not define a yaml-assignable type.".F(initName));
+				throw new InvalidDataException("{0}Init does not define a yaml-assignable type.".F(initInstance[0]));
 
 			loader.Invoke(init, new[] { initYaml });
 			return init;
@@ -74,6 +78,9 @@ namespace OpenRA
 
 				var initTypeName = init.GetType().Name;
 				var initName = initTypeName.Substring(0, initTypeName.Length - 4);
+				if (!string.IsNullOrEmpty(init.InstanceName))
+					initName += ActorInfo.TraitInstanceSeparator + init.InstanceName;
+
 				ret.Nodes.Add(new MiniYamlNode(initName, init.Save()));
 			}
 

OpenRA.Game/Traits/TraitsInterfaces.cs

@@ -327,6 +327,9 @@ namespace OpenRA.Traits
 
 	public abstract class TraitInfo : ITraitInfoInterface
 	{
+		// Value is set using reflection during TraitInfo creation
+		public readonly string InstanceName = null;
+
 		public abstract object Create(ActorInitializer init);
 	}
 

OpenRA.Mods.Common/Graphics/ActorPreview.cs

@@ -44,7 +44,17 @@ namespace OpenRA.Mods.Common.Graphics
 
 		public T GetOrDefault<T>(TraitInfo info) where T : ActorInit
 		{
-			return dict.GetOrDefault<T>();
+			var inits = dict.WithInterface<T>();
+
+			// Traits tagged with an instance name prefer inits with the same name.
+			// If a more specific init is not available, fall back to an unnamed init.
+			// If duplicate inits are defined, take the last to match standard yaml override expectations
+			if (info != null && !string.IsNullOrEmpty(info.InstanceName))
+				return inits.LastOrDefault(i => i.InstanceName == info.InstanceName) ??
+				       inits.LastOrDefault(i => string.IsNullOrEmpty(i.InstanceName));
+
+			// Untagged traits will only use untagged inits
+			return inits.LastOrDefault(i => string.IsNullOrEmpty(i.InstanceName));
 		}
 
 		public T Get<T>(TraitInfo info) where T : ActorInit

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

@@ -30,12 +30,16 @@ namespace OpenRA.Mods.Common.Scripting
 		ActorInit CreateInit(string initName, LuaValue value)
 		{
 			// Find the requested type
-			var initType = Game.ModData.ObjectCreator.FindType(initName + "Init");
+			var initInstance = initName.Split(ActorInfo.TraitInstanceSeparator);
+			var initType = Game.ModData.ObjectCreator.FindType(initInstance[0] + "Init");
 			if (initType == null)
-				throw new LuaException("Unknown initializer type '{0}'".F(initName));
+				throw new LuaException("Unknown initializer type '{0}'".F(initInstance[0]));
 
 			// Construct the ActorInit.
 			var init = (ActorInit)FormatterServices.GetUninitializedObject(initType);
+			if (initInstance.Length > 1)
+				initType.GetField("InstanceName").SetValue(init, initInstance[1]);
+
 			var initializers = initType.GetMethods(BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Instance)
 				.Where(m => m.Name == "Initialize" && m.GetParameters().Length == 1);
 
@@ -55,7 +59,7 @@ namespace OpenRA.Mods.Common.Scripting
 			}
 
 			var types = initializers.Select(y => y.GetParameters()[0].ParameterType.Name).JoinWith(", ");
-			throw new LuaException("Invalid data type for '{0}' (expected one of {1})".F(initName, types));
+			throw new LuaException("Invalid data type for '{0}' (expected one of {1})".F(initInstance[0], types));
 		}
 
 		[Desc("Create a new actor. initTable specifies a list of key-value pairs that defines the initial parameters for the actor's traits.")]