Added an update rule for adding ControlGroups

OpenRA.Mods.Common/UpdateRules/Rules/20210321/AddControlGroups.cs

@@ -0,0 +1,32 @@
+#region Copyright & License Information
+/*
+ * Copyright 2007-2022 The OpenRA Developers (see AUTHORS)
+ * This file is part of OpenRA, which is free software. It is made
+ * available to you under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, either version 3 of
+ * the License, or (at your option) any later version. For more
+ * information, see COPYING.
+ */
+#endregion
+
+using System.Collections.Generic;
+using System.Linq;
+
+namespace OpenRA.Mods.Common.UpdateRules.Rules
+{
+	public class AddControlGroups : UpdateRule
+	{
+		public override string Name => "Add new ControlGroups trait.";
+
+		public override string Description => "A new trait ControlGroups was added, splitting logic away from Selection.";
+
+		public override IEnumerable<string> UpdateActorNode(ModData modData, MiniYamlNode actorNode)
+		{
+			if (actorNode.ChildrenMatching("Selection").Any(x => !x.IsRemoval())
+			    && !actorNode.ChildrenMatching("ControlGroups").Any())
+				actorNode.AddNode(new MiniYamlNode("ControlGroups", ""));
+
+			yield break;
+		}
+	}
+}

OpenRA.Mods.Common/UpdateRules/UpdatePath.cs

@@ -97,6 +97,7 @@ namespace OpenRA.Mods.Common.UpdateRules
 				new UnhardcodeVeteranProductionIconOverlay(),
 				new RenameContrailProperties(),
 				new RemoveDomainIndex(),
+				new AddControlGroups(),
 			}),
 
 			new UpdatePath("playtest-20221203", new UpdateRule[]