Automatically switch mods when connecting to a server / replay.

OpenRA.Game/Network/OrderManager.cs

@@ -51,6 +51,8 @@ namespace OpenRA.Network
 
 		public readonly ReadOnlyList<ChatLine> ChatCache;
 
+		bool disposed;
+
 		static void OutOfSync(int frame)
 		{
 			throw new InvalidOperationException("Out of sync in frame {0}.\n Compare syncreport.log with other players.".F(frame));
@@ -122,8 +124,16 @@ namespace OpenRA.Network
 				});
 
 			foreach (var p in immediatePackets)
+			{
 				foreach (var o in p.Second.ToOrderList(World))
+				{
 					UnitOrders.ProcessOrder(this, World, p.First, o);
+
+					// A mod switch or other event has pulled the ground from beneath us
+					if (disposed)
+						return;
+				}
+			}
 		}
 
 		Dictionary<int, byte[]> syncForFrame = new Dictionary<int, byte[]>();
@@ -213,6 +223,7 @@ namespace OpenRA.Network
 
 		public void Dispose()
 		{
+			disposed = true;
 			if (Connection != null)
 				Connection.Dispose();
 		}

OpenRA.Game/Network/ReplayConnection.cs

@@ -33,9 +33,12 @@ namespace OpenRA.Network
 		public readonly int TickCount;
 		public readonly bool IsValid;
 		public readonly Session LobbyInfo;
+		public readonly string Filename;
 
 		public ReplayConnection(string replayFilename)
 		{
+			Filename = replayFilename;
+
 			// Parse replay data into a struct that can be fed to the game in chunks
 			// to avoid issues with all immediate orders being resolved on the first tick.
 			using (var rs = File.OpenRead(replayFilename))

OpenRA.Game/Network/UnitOrders.cs

@@ -119,10 +119,27 @@ namespace OpenRA.Network
 
 				case "HandshakeRequest":
 					{
-						// TODO: Switch to the server's mod if we have it
-						// Otherwise send the handshake with our current settings and let the server reject us
+						// Switch to the server's mod if we need and are able to
 						var mod = Game.modData.Manifest.Mod;
+						var request = HandshakeRequest.Deserialize(order.TargetString);
 
+						ModMetadata serverMod;
+						if (request.Mod != mod.Id &&
+							ModMetadata.AllMods.TryGetValue(request.Mod, out serverMod) &&
+							serverMod.Version == request.Version)
+						{
+							var replay = orderManager.Connection as ReplayConnection;
+							var launchCommand = replay != null ?
+								"Launch.Replay=" + replay.Filename :
+								"Launch.Connect=" + orderManager.Host + ":" + orderManager.Port;
+
+							Game.modData.LoadScreen.Display();
+							Game.InitializeMod(request.Mod, new Arguments(launchCommand));
+
+							break;
+						}
+
+						// Otherwise send the handshake with our current settings and let the server reject us
 						var info = new Session.Client()
 						{
 							Name = Game.Settings.Player.Name,