Rework MapPreview custom rule handling.

The previous asynchronous approach did not work particularly well,
leading to large janks when switching to custom maps or opening the
mission browser.

This commit introduces two key changes:

 * Rule loading for WorldActorInfo and PlayerActorInfo is made
   synchronous, in preparation for the next commit which will
   significantly optimize this path.
 * The full ruleset loading, which is required for map validation,
   is moved to the server-side and managed by a new ServerMapStatusCache.
   The previous syntax check is expanded to include the ability to run
   lint tests.

OpenRA.Game/Map/MapPreview.cs

@@ -38,9 +38,6 @@ namespace OpenRA
 		Remote = 4
 	}
 
-	// Used for verifying map availability in the lobby
-	public enum MapRuleStatus { Unknown, Cached, Invalid }
-
 	[SuppressMessage("StyleCop.CSharp.NamingRules",
 		"SA1307:AccessibleFieldsMustBeginWithUpperCaseLetter",
 		Justification = "Fields names must match the with the remote API.")]
@@ -85,45 +82,50 @@ namespace OpenRA
 			public MapClassification Class;
 			public MapVisibility Visibility;
 
-			Lazy<Ruleset> rules;
+			public MiniYaml RuleDefinitions;
-			public bool InvalidCustomRules { get; private set; }
+			public MiniYaml WeaponDefinitions;
-			public bool DefinesUnsafeCustomRules { get; private set; }
+			public MiniYaml VoiceDefinitions;
-			public bool RulesLoaded { get; private set; }
+			public MiniYaml MusicDefinitions;
+			public MiniYaml NotificationDefinitions;
+			public MiniYaml SequenceDefinitions;
+			public MiniYaml ModelSequenceDefinitions;
 
-			public ActorInfo WorldActorInfo => rules?.Value.Actors[SystemActors.World];
+			public ActorInfo WorldActorInfo { get; private set; }
-			public ActorInfo PlayerActorInfo => rules?.Value.Actors[SystemActors.Player];
+			public ActorInfo PlayerActorInfo { get; private set; }
 
-			public void SetRulesetGenerator(ModData modData, Func<(Ruleset Ruleset, bool DefinesUnsafeCustomRules)> generator)
+			static MiniYaml LoadRuleSection(Dictionary<string, MiniYaml> yaml, string section)
 			{
-				InvalidCustomRules = false;
+				if (!yaml.TryGetValue(section, out var node))
-				RulesLoaded = false;
+					return null;
-				DefinesUnsafeCustomRules = false;
 
-				// Note: multiple threads may try to access the value at the same time
+				return node;
-				// We rely on the thread-safety guarantees given by Lazy<T> to prevent race conitions.
+			}
-				// If you're thinking about replacing this, then you must be careful to keep this safe.
+
-				rules = Exts.Lazy(() =>
+			public void SetCustomRules(ModData modData, IReadOnlyFileSystem fileSystem, Dictionary<string, MiniYaml> yaml)
+			{
+				RuleDefinitions = LoadRuleSection(yaml, "Rules");
+				WeaponDefinitions = LoadRuleSection(yaml, "Weapons");
+				VoiceDefinitions = LoadRuleSection(yaml, "Voices");
+				MusicDefinitions = LoadRuleSection(yaml, "Music");
+				NotificationDefinitions = LoadRuleSection(yaml, "Notifications");
+				SequenceDefinitions = LoadRuleSection(yaml, "Sequences");
+				ModelSequenceDefinitions = LoadRuleSection(yaml, "ModelSequences");
+
+				try
 				{
-					if (generator == null)
+					var rules = Ruleset.Load(modData, fileSystem, TileSet, RuleDefinitions,
-						return Ruleset.LoadDefaultsForTileSet(modData, TileSet);
+						WeaponDefinitions, VoiceDefinitions, NotificationDefinitions,
+						MusicDefinitions, SequenceDefinitions, ModelSequenceDefinitions);
 
-					try
+					WorldActorInfo = rules.Actors[SystemActors.World];
-					{
+					PlayerActorInfo = rules.Actors[SystemActors.Player];
-						var ret = generator();
+				}
-						DefinesUnsafeCustomRules = ret.DefinesUnsafeCustomRules;
+				catch (Exception e)
-						return ret.Ruleset;
+				{
-					}
+					Log.Write("debug", "Failed to load rules for `{0}` with error :{1}", Title, e.Message);
-					catch (Exception e)
+					WorldActorInfo = modData.DefaultRules.Actors[SystemActors.World];
-					{
+					PlayerActorInfo = modData.DefaultRules.Actors[SystemActors.Player];
-						Log.Write("debug", "Failed to load rules for `{0}` with error :{1}", Title, e.Message);
+				}
-						InvalidCustomRules = true;
-						return Ruleset.LoadDefaultsForTileSet(modData, TileSet);
-					}
-					finally
-					{
-						RulesLoaded = true;
-					}
-				});
 			}
 
 			public InnerData Clone()
@@ -132,7 +134,7 @@ namespace OpenRA
 			}
 		}
 
-		static readonly CPos[] NoSpawns = new CPos[] { };
+		static readonly CPos[] NoSpawns = { };
 		readonly MapCache cache;
 		readonly ModData modData;
 
@@ -156,22 +158,9 @@ namespace OpenRA
 		public MapClassification Class => innerData.Class;
 		public MapVisibility Visibility => innerData.Visibility;
 
-		public bool InvalidCustomRules => innerData.InvalidCustomRules;
-		public bool RulesLoaded => innerData.RulesLoaded;
-
 		public ActorInfo WorldActorInfo => innerData.WorldActorInfo;
 		public ActorInfo PlayerActorInfo => innerData.PlayerActorInfo;
 
-		public bool DefinesUnsafeCustomRules
-		{
-			get
-			{
-				// Force lazy rules to be evaluated
-				var force = innerData.WorldActorInfo;
-				return innerData.DefinesUnsafeCustomRules;
-			}
-		}
-
 		public long DownloadBytes { get; private set; }
 		public int DownloadPercentage { get; private set; }
 
@@ -197,6 +186,20 @@ namespace OpenRA
 			generatingMinimap = false;
 		}
 
+		public bool DefinesUnsafeCustomRules()
+		{
+			return Ruleset.DefinesUnsafeCustomRules(modData, this, innerData.RuleDefinitions,
+				innerData.WeaponDefinitions, innerData.VoiceDefinitions,
+				innerData.NotificationDefinitions, innerData.SequenceDefinitions);
+		}
+
+		public Ruleset LoadRuleset()
+		{
+			return Ruleset.Load(modData, this, TileSet, innerData.RuleDefinitions,
+				innerData.WeaponDefinitions, innerData.VoiceDefinitions, innerData.NotificationDefinitions,
+				innerData.MusicDefinitions, innerData.SequenceDefinitions, innerData.ModelSequenceDefinitions);
+		}
+
 		public MapPreview(ModData modData, string uid, MapGridType gridType, MapCache cache)
 		{
 			this.cache = cache;
@@ -308,21 +311,7 @@ namespace OpenRA
 				newData.Status = MapStatus.Unavailable;
 			}
 
-			newData.SetRulesetGenerator(modData, () =>
+			newData.SetCustomRules(modData, this, yaml);
-			{
-				var ruleDefinitions = LoadRuleSection(yaml, "Rules");
-				var weaponDefinitions = LoadRuleSection(yaml, "Weapons");
-				var voiceDefinitions = LoadRuleSection(yaml, "Voices");
-				var musicDefinitions = LoadRuleSection(yaml, "Music");
-				var notificationDefinitions = LoadRuleSection(yaml, "Notifications");
-				var sequenceDefinitions = LoadRuleSection(yaml, "Sequences");
-				var modelSequenceDefinitions = LoadRuleSection(yaml, "ModelSequences");
-				var rules = Ruleset.Load(modData, this, TileSet, ruleDefinitions, weaponDefinitions,
-					voiceDefinitions, notificationDefinitions, musicDefinitions, sequenceDefinitions, modelSequenceDefinitions);
-				var flagged = Ruleset.DefinesUnsafeCustomRules(modData, this, ruleDefinitions,
-					weaponDefinitions, voiceDefinitions, notificationDefinitions, sequenceDefinitions);
-				return (rules, flagged);
-			});
 
 			if (p.Contains("map.png"))
 				using (var dataStream = p.GetStream("map.png"))
@@ -332,19 +321,6 @@ namespace OpenRA
 			innerData = newData;
 		}
 
-		MiniYaml LoadRuleSection(Dictionary<string, MiniYaml> yaml, string section)
-		{
-			if (!yaml.TryGetValue(section, out var node))
-				return null;
-
-			return node;
-		}
-
-		public void PreloadRules()
-		{
-			var unused = WorldActorInfo;
-		}
-
 		public void UpdateRemoteSearch(MapStatus status, MiniYaml yaml, Action<MapPreview> parseMetadata = null)
 		{
 			var newData = innerData.Clone();
@@ -389,23 +365,9 @@ namespace OpenRA
 					var playersString = Encoding.UTF8.GetString(Convert.FromBase64String(r.players_block));
 					newData.Players = new MapPlayers(MiniYaml.FromString(playersString));
 
-					newData.SetRulesetGenerator(modData, () =>
+					var rulesString = Encoding.UTF8.GetString(Convert.FromBase64String(r.rules));
-					{
+					var rulesYaml = new MiniYaml("", MiniYaml.FromString(rulesString)).ToDictionary();
-						var rulesString = Encoding.UTF8.GetString(Convert.FromBase64String(r.rules));
+					newData.SetCustomRules(modData, this, rulesYaml);
-						var rulesYaml = new MiniYaml("", MiniYaml.FromString(rulesString)).ToDictionary();
-						var ruleDefinitions = LoadRuleSection(rulesYaml, "Rules");
-						var weaponDefinitions = LoadRuleSection(rulesYaml, "Weapons");
-						var voiceDefinitions = LoadRuleSection(rulesYaml, "Voices");
-						var musicDefinitions = LoadRuleSection(rulesYaml, "Music");
-						var notificationDefinitions = LoadRuleSection(rulesYaml, "Notifications");
-						var sequenceDefinitions = LoadRuleSection(rulesYaml, "Sequences");
-						var modelSequenceDefinitions = LoadRuleSection(rulesYaml, "ModelSequences");
-						var rules = Ruleset.Load(modData, this, TileSet, ruleDefinitions, weaponDefinitions,
-							voiceDefinitions, notificationDefinitions, musicDefinitions, sequenceDefinitions, modelSequenceDefinitions);
-						var flagged = Ruleset.DefinesUnsafeCustomRules(modData, this, ruleDefinitions,
-							weaponDefinitions, voiceDefinitions, notificationDefinitions, sequenceDefinitions);
-						return (rules, flagged);
-					});
 				}
 				catch (Exception e)
 				{
@@ -473,21 +435,19 @@ namespace OpenRA
 
 					mapInstallPackage.Update(mapFilename, fileStream.ToArray());
 					Log.Write("debug", "Downloaded map to '{0}'", mapFilename);
-					Game.RunAfterTick(() =>
+
+					var package = mapInstallPackage.OpenPackage(mapFilename, modData.ModFiles);
+					if (package == null)
+						innerData.Status = MapStatus.DownloadError;
+					else
 					{
-						var package = mapInstallPackage.OpenPackage(mapFilename, modData.ModFiles);
+						UpdateFromMap(package, mapInstallPackage, MapClassification.User, null, GridType);
-						if (package == null)
+						Game.RunAfterTick(onSuccess);
-							innerData.Status = MapStatus.DownloadError;
+					}
-						else
-						{
-							UpdateFromMap(package, mapInstallPackage, MapClassification.User, null, GridType);
-							onSuccess();
-						}
-					});
 				}
 				catch (Exception e)
 				{
-					Console.WriteLine(e.Message);
+					Log.Write("debug", "Map installation failed with error: {0}", e);
 					innerData.Status = MapStatus.DownloadError;
 				}
 			});

OpenRA.Game/Network/Session.cs

@@ -15,6 +15,7 @@ using System.Linq;
 using System.Net;
 using System.Net.Sockets;
 using OpenRA.Primitives;
+using OpenRA.Server;
 
 namespace OpenRA.Network
 {
@@ -218,10 +219,21 @@ namespace OpenRA.Network
 			public bool IsEnabled => Value == "True";
 		}
 
+		[Flags]
+		public enum MapStatus
+		{
+			Unknown = 0,
+			Validating = 1,
+			Playable = 2,
+			Incompatible = 4,
+			UnsafeCustomRules = 8,
+		}
+
 		public class Global
 		{
 			public string ServerName;
 			public string Map;
+			public MapStatus MapStatus;
 			public int RandomSeed = 0;
 			public bool AllowSpectators = true;
 			public string GameUid;

OpenRA.Game/Server/MapStatusCache.cs

@@ -0,0 +1,100 @@
+#region Copyright & License Information
+/*
+ * Copyright 2007-2021 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;
+using System.Collections.Generic;
+using System.Threading;
+using OpenRA.Network;
+
+namespace OpenRA.Server
+{
+	public interface ILintServerMapPass { void Run(Action<string> emitError, Action<string> emitWarning, ModData modData, MapPreview map, Ruleset mapRules); }
+
+	public class MapStatusCache
+	{
+		readonly Dictionary<MapPreview, Session.MapStatus> cache = new Dictionary<MapPreview, Session.MapStatus>();
+		readonly Action<string, Session.MapStatus> onStatusChanged;
+		readonly bool enableRemoteLinting;
+		readonly ModData modData;
+
+		public MapStatusCache(ModData modData, Action<string, Session.MapStatus> onStatusChanged, bool enableRemoteLinting)
+		{
+			this.modData = modData;
+			this.enableRemoteLinting = enableRemoteLinting;
+			this.onStatusChanged = onStatusChanged;
+		}
+
+		void RunLintTests(MapPreview map, Ruleset rules)
+		{
+			var status = cache[map];
+			var failed = false;
+
+			Action<string> onLintFailure = message =>
+			{
+				Log.Write("server", "Map {0} failed lint with error: {1}", map.Title, message);
+				failed = true;
+			};
+
+			Action<string> onLintWarning = _ => { };
+
+			foreach (var customMapPassType in modData.ObjectCreator.GetTypesImplementing<ILintServerMapPass>())
+			{
+				try
+				{
+					var customMapPass = (ILintServerMapPass)modData.ObjectCreator.CreateBasic(customMapPassType);
+					customMapPass.Run(onLintFailure, onLintWarning, modData, map, rules);
+				}
+				catch (Exception e)
+				{
+					onLintFailure(e.ToString());
+				}
+			}
+
+			status &= ~Session.MapStatus.Validating;
+			status |= failed ? Session.MapStatus.Incompatible : Session.MapStatus.Playable;
+
+			cache[map] = status;
+			onStatusChanged?.Invoke(map.Uid, status);
+		}
+
+		public Session.MapStatus this[MapPreview map]
+		{
+			get
+			{
+				if (cache.TryGetValue(map, out var status))
+					return status;
+
+				Ruleset rules = null;
+				try
+				{
+					rules = map.LoadRuleset();
+
+					// Locally installed maps are assumed to not require linting
+					status = enableRemoteLinting && map.Status != MapStatus.Available ? Session.MapStatus.Validating : Session.MapStatus.Playable;
+					if (map.DefinesUnsafeCustomRules())
+						status |= Session.MapStatus.UnsafeCustomRules;
+				}
+				catch (Exception e)
+				{
+					Log.Write("server", "Failed to load rules for `{0}` with error :{1}", map.Title, e.Message);
+					status = Session.MapStatus.Incompatible;
+				}
+
+				cache[map] = status;
+
+				if ((status & Session.MapStatus.Validating) != 0)
+					ThreadPool.QueueUserWorkItem(_ => RunLintTests(map, rules));
+
+				return status;
+			}
+		}
+	}
+}

OpenRA.Game/Server/ProtocolVersion.cs

@@ -68,6 +68,6 @@ namespace OpenRA.Server
 		// The protocol for server and world orders
 		// This applies after the handshake has completed, and is provided to support
 		// alternative server implementations that wish to support multiple versions in parallel
-		public const int Orders = 11;
+		public const int Orders = 12;
 	}
 }

OpenRA.Game/Server/Server.cs

@@ -61,6 +61,7 @@ namespace OpenRA.Server
 
 		// Managed by LobbyCommands
 		public MapPreview Map;
+		public readonly MapStatusCache MapStatusCache;
 		public GameSave GameSave = null;
 
 		readonly int randomSeed;
@@ -170,6 +171,17 @@ namespace OpenRA.Server
 			}.Serialize());
 		}
 
+		void MapStatusChanged(string uid, Session.MapStatus status)
+		{
+			lock (LobbyInfo)
+			{
+				if (LobbyInfo.GlobalSettings.Map == uid)
+					LobbyInfo.GlobalSettings.MapStatus = status;
+
+				SyncLobbyInfo();
+			}
+		}
+
 		public Server(List<IPEndPoint> endpoints, ServerSettings settings, ModData modData, ServerType type)
 		{
 			Log.AddChannel("server", "server.log", true);
@@ -229,12 +241,16 @@ namespace OpenRA.Server
 
 			serverTraits.TrimExcess();
 
+			Map = ModData.MapCache[settings.Map];
+			MapStatusCache = new MapStatusCache(modData, MapStatusChanged, type == ServerType.Dedicated && settings.EnableLintChecks);
+
 			LobbyInfo = new Session
 			{
 				GlobalSettings =
 				{
 					RandomSeed = randomSeed,
-					Map = settings.Map,
+					Map = Map.Uid,
+					MapStatus = Session.MapStatus.Unknown,
 					ServerName = settings.Name,
 					EnableSingleplayer = settings.EnableSingleplayer || Type != ServerType.Dedicated,
 					EnableSyncReports = settings.EnableSyncReports,
@@ -254,6 +270,8 @@ namespace OpenRA.Server
 
 			new Thread(_ =>
 			{
+				// Initial status is set off the main thread to avoid triggering a load screen when joining a skirmish game
+				LobbyInfo.GlobalSettings.MapStatus = MapStatusCache[Map];
 				foreach (var t in serverTraits.WithInterface<INotifyServerStart>())
 					t.ServerStarted(this);
 
@@ -541,7 +559,7 @@ namespace OpenRA.Server
 								SendOrderTo(newConn, "Message", motd);
 						}
 
-						if (Map.DefinesUnsafeCustomRules)
+						if ((LobbyInfo.GlobalSettings.MapStatus & Session.MapStatus.UnsafeCustomRules) != 0)
 							SendOrderTo(newConn, "Message", "This map contains custom rules. Game experience may change.");
 
 						if (!LobbyInfo.GlobalSettings.EnableSingleplayer)

OpenRA.Game/Settings.cs

@@ -91,6 +91,9 @@ namespace OpenRA
 		[Desc("For dedicated servers only, save replays for all games played.")]
 		public bool RecordReplays = false;
 
+		[Desc("For dedicated servers only, treat maps that fail the lint checks as invalid.")]
+		public bool EnableLintChecks = true;
+
 		public ServerSettings Clone()
 		{
 			return (ServerSettings)MemberwiseClone();

OpenRA.Mods.Common/ServerTraits/LobbyCommands.cs

@@ -431,6 +431,7 @@ namespace OpenRA.Mods.Common.Server
 
 						var oldSlots = server.LobbyInfo.Slots.Keys.ToArray();
 						server.Map = server.ModData.MapCache[server.LobbyInfo.GlobalSettings.Map];
+						server.LobbyInfo.GlobalSettings.MapStatus = server.MapStatusCache[server.Map];
 
 						server.LobbyInfo.Slots = server.Map.Players.Players
 							.Select(p => MakeSlotFromPlayerReference(p.Value))
@@ -492,7 +493,7 @@ namespace OpenRA.Mods.Common.Server
 
 						server.SendMessage("{0} changed the map to {1}.".F(client.Name, server.Map.Title));
 
-						if (server.Map.DefinesUnsafeCustomRules)
+						if ((server.LobbyInfo.GlobalSettings.MapStatus & Session.MapStatus.UnsafeCustomRules) != 0)
 							server.SendMessage("This map contains custom rules. Game experience may change.");
 
 						if (!server.LobbyInfo.GlobalSettings.EnableSingleplayer)

OpenRA.Mods.Common/Widgets/Logic/Lobby/LobbyLogic.cs

@@ -58,6 +58,8 @@ namespace OpenRA.Mods.Common.Widgets.Logic
 		readonly TabCompletionLogic tabCompletion = new TabCompletionLogic();
 
 		MapPreview map;
+		Session.MapStatus mapStatus;
+
 		bool addBotOnMapLoad;
 		bool disableTeamChat;
 		bool insufficientPlayerSpawns;
@@ -67,6 +69,8 @@ namespace OpenRA.Mods.Common.Widgets.Logic
 
 		readonly string chatLineSound = ChromeMetrics.Get<string>("ChatLineSound");
 
+		bool MapIsPlayable => (mapStatus & Session.MapStatus.Playable) == Session.MapStatus.Playable;
+
 		// Listen for connection failures
 		void ConnectionStateChanged(OrderManager om)
 		{
@@ -131,7 +135,7 @@ namespace OpenRA.Mods.Common.Widgets.Logic
 			var mapContainer = Ui.LoadWidget("MAP_PREVIEW", lobby.Get("MAP_PREVIEW_ROOT"), new WidgetArgs
 			{
 				{ "orderManager", orderManager },
-				{ "getMap", (Func<MapPreview>)(() => map) },
+				{ "getMap", (Func<(MapPreview, Session.MapStatus)>)(() => (map, mapStatus)) },
 				{
 					"onMouseDown", (Action<MapPreviewWidget, MapPreview, MouseInput>)((preview, mapPreview, mi) =>
 						LobbyUtils.SelectSpawnPoint(orderManager, preview, mapPreview, mi))
@@ -163,8 +167,7 @@ namespace OpenRA.Mods.Common.Widgets.Logic
 
 			var gameStarting = false;
 			Func<bool> configurationDisabled = () => !Game.IsHost || gameStarting ||
-				panel == PanelType.Kick || panel == PanelType.ForceStart ||
+				panel == PanelType.Kick || panel == PanelType.ForceStart || !MapIsPlayable ||
-				!map.RulesLoaded || map.InvalidCustomRules ||
 				orderManager.LocalClient == null || orderManager.LocalClient.IsReady;
 
 			var mapButton = lobby.GetOrNull<ButtonWidget>("CHANGEMAP_BUTTON");
@@ -330,7 +333,6 @@ namespace OpenRA.Mods.Common.Widgets.Logic
 			optionsTab.IsHighlighted = () => panel == PanelType.Options;
 			optionsTab.IsDisabled = OptionsTabDisabled;
 			optionsTab.OnClick = () => panel = PanelType.Options;
-			optionsTab.GetText = () => !map.RulesLoaded ? "Loading..." : optionsTab.Text;
 
 			var playersTab = tabContainer.Get<ButtonWidget>("PLAYERS_TAB");
 			playersTab.IsHighlighted = () => panel == PanelType.Players;
@@ -476,7 +478,7 @@ namespace OpenRA.Mods.Common.Widgets.Logic
 
 		bool OptionsTabDisabled()
 		{
-			return !map.RulesLoaded || map.InvalidCustomRules || panel == PanelType.Kick || panel == PanelType.ForceStart;
+			return !MapIsPlayable || panel == PanelType.Kick || panel == PanelType.ForceStart;
 		}
 
 		public override void Tick()
@@ -505,14 +507,9 @@ namespace OpenRA.Mods.Common.Widgets.Logic
 			return true;
 		}
 
-		void LoadMapPreviewRules(MapPreview map)
-		{
-			// Force map rules to be loaded on this background thread
-			new Task(map.PreloadRules).Start();
-		}
-
 		void UpdateCurrentMap()
 		{
+			mapStatus = orderManager.LobbyInfo.GlobalSettings.MapStatus;
 			var uid = orderManager.LobbyInfo.GlobalSettings.Map;
 			if (map.Uid == uid)
 				return;
@@ -520,39 +517,22 @@ namespace OpenRA.Mods.Common.Widgets.Logic
 			map = modData.MapCache[uid];
 			if (map.Status == MapStatus.Available)
 			{
-				// Maps need to be validated and pre-loaded before they can be accessed
+				// Tell the server that we have the map
-				var currentMap = map;
+				orderManager.IssueOrder(Order.Command("state {0}".F(Session.ClientState.NotReady)));
-				new Task(() =>
+
+				if (addBotOnMapLoad)
 				{
-					// Force map rules to be loaded on this background thread
+					var slot = orderManager.LobbyInfo.FirstEmptyBotSlot();
-					currentMap.PreloadRules();
+					var bot = map.PlayerActorInfo.TraitInfos<IBotInfo>().Select(t => t.Type).FirstOrDefault();
-					Game.RunAfterTick(() =>
+					var botController = orderManager.LobbyInfo.Clients.FirstOrDefault(c => c.IsAdmin);
-					{
+					if (slot != null && bot != null)
-						// Map may have changed in the meantime
+						orderManager.IssueOrder(Order.Command("slot_bot {0} {1} {2}".F(slot, botController.Index, bot)));
-						if (currentMap != map)
-							return;
 
-						// Tell the server that we have the map
+					addBotOnMapLoad = false;
-						if (!currentMap.InvalidCustomRules)
+				}
-							orderManager.IssueOrder(Order.Command("state {0}".F(Session.ClientState.NotReady)));
-
-						if (addBotOnMapLoad)
-						{
-							var slot = orderManager.LobbyInfo.FirstEmptyBotSlot();
-							var bot = currentMap.PlayerActorInfo.TraitInfos<IBotInfo>().Select(t => t.Type).FirstOrDefault();
-							var botController = orderManager.LobbyInfo.Clients.FirstOrDefault(c => c.IsAdmin);
-							if (slot != null && bot != null)
-								orderManager.IssueOrder(Order.Command("slot_bot {0} {1} {2}".F(slot, botController.Index, bot)));
-
-							addBotOnMapLoad = false;
-						}
-					});
-				}).Start();
 			}
-			else if (map.Status == MapStatus.DownloadAvailable)
+			else if (map.Status != MapStatus.DownloadAvailable && Game.Settings.Game.AllowDownloading)
-				LoadMapPreviewRules(map);
+				modData.MapCache.QueryRemoteMapDetails(services.MapRepository, new[] { uid });
-			else if (Game.Settings.Game.AllowDownloading)
-				modData.MapCache.QueryRemoteMapDetails(services.MapRepository, new[] { uid }, LoadMapPreviewRules);
 		}
 
 		void UpdatePlayerList()
@@ -626,7 +606,7 @@ namespace OpenRA.Mods.Common.Widgets.Logic
 					LobbyUtils.SetupEditableTeamWidget(template, slot, client, orderManager, map);
 					LobbyUtils.SetupEditableHandicapWidget(template, slot, client, orderManager, map);
 					LobbyUtils.SetupEditableSpawnWidget(template, slot, client, orderManager, map);
-					LobbyUtils.SetupEditableReadyWidget(template, slot, client, orderManager, map);
+					LobbyUtils.SetupEditableReadyWidget(template, slot, client, orderManager, map, MapIsPlayable);
 				}
 				else
 				{
@@ -686,7 +666,7 @@ namespace OpenRA.Mods.Common.Widgets.Logic
 					LobbyUtils.SetupEditableNameWidget(template, null, c, orderManager, worldRenderer);
 
 					if (client.IsAdmin)
-						LobbyUtils.SetupEditableReadyWidget(template, null, client, orderManager, map);
+						LobbyUtils.SetupEditableReadyWidget(template, null, client, orderManager, map, MapIsPlayable);
 					else
 						LobbyUtils.HideReadyWidgets(template);
 				}

OpenRA.Mods.Common/Widgets/Logic/Lobby/LobbyOptionsLogic.cs

@@ -30,7 +30,6 @@ namespace OpenRA.Mods.Common.Widgets.Logic
 		readonly OrderManager orderManager;
 		readonly Func<bool> configurationDisabled;
 		MapPreview mapPreview;
-		bool validOptions;
 
 		[ObjectCreator.UseCtor]
 		internal LobbyOptionsLogic(Widget widget, OrderManager orderManager, Func<MapPreview> getMap, Func<bool> configurationDisabled)
@@ -42,7 +41,6 @@ namespace OpenRA.Mods.Common.Widgets.Logic
 			panel = (ScrollPanelWidget)widget;
 			optionsContainer = widget.Get("LOBBY_OPTIONS");
 			yMargin = optionsContainer.Bounds.Y;
-			optionsContainer.IsVisible = () => validOptions;
 			checkboxRowTemplate = optionsContainer.Get("CHECKBOX_ROW_TEMPLATE");
 			dropdownRowTemplate = optionsContainer.Get("DROPDOWN_ROW_TEMPLATE");
 
@@ -56,24 +54,18 @@ namespace OpenRA.Mods.Common.Widgets.Logic
 			if (newMapPreview == mapPreview)
 				return;
 
-			if (newMapPreview.RulesLoaded)
+			// We are currently enumerating the widget tree and so can't modify any layout
+			// Defer it to the end of tick instead
+			Game.RunAfterTick(() =>
 			{
-				// We are currently enumerating the widget tree and so can't modify any layout
+				mapPreview = newMapPreview;
-				// Defer it to the end of tick instead
+				RebuildOptions();
-				Game.RunAfterTick(() =>
+			});
-				{
-					mapPreview = newMapPreview;
-					RebuildOptions();
-					validOptions = true;
-				});
-			}
-			else
-				validOptions = false;
 		}
 
 		void RebuildOptions()
 		{
-			if (mapPreview == null || mapPreview.WorldActorInfo == null || mapPreview.InvalidCustomRules)
+			if (mapPreview == null || mapPreview.WorldActorInfo == null)
 				return;
 
 			optionsContainer.RemoveChildren();

OpenRA.Mods.Common/Widgets/Logic/Lobby/LobbyUtils.cs

@@ -630,13 +630,12 @@ namespace OpenRA.Mods.Common.Widgets.Logic
 			HideChildWidget(parent, "SPAWN_DROPDOWN");
 		}
 
-		public static void SetupEditableReadyWidget(Widget parent, Session.Slot s, Session.Client c, OrderManager orderManager, MapPreview map)
+		public static void SetupEditableReadyWidget(Widget parent, Session.Slot s, Session.Client c, OrderManager orderManager, MapPreview map, bool isEnabled)
 		{
 			var status = parent.Get<CheckboxWidget>("STATUS_CHECKBOX");
 			status.IsChecked = () => orderManager.LocalClient.IsReady || c.Bot != null;
 			status.IsVisible = () => true;
-			status.IsDisabled = () => c.Bot != null || map.Status != MapStatus.Available ||
+			status.IsDisabled = () => c.Bot != null || map.Status != MapStatus.Available || !isEnabled;
-				!map.RulesLoaded || map.InvalidCustomRules;
 
 			var state = orderManager.LocalClient.IsReady ? Session.ClientState.NotReady : Session.ClientState.Ready;
 			status.OnClick = () => orderManager.IssueOrder(Order.Command("state {0}".F(state)));

OpenRA.Mods.Common/Widgets/Logic/Lobby/MapPreviewLogic.cs

@@ -24,8 +24,9 @@ namespace OpenRA.Mods.Common.Widgets.Logic
 		int blinkTick;
 
 		[ObjectCreator.UseCtor]
-		internal MapPreviewLogic(Widget widget, ModData modData, OrderManager orderManager, Func<MapPreview> getMap, Action<MapPreviewWidget, MapPreview, MouseInput> onMouseDown,
+		internal MapPreviewLogic(Widget widget, ModData modData, OrderManager orderManager, Func<(MapPreview Map, Session.MapStatus Status)> getMap,
-			Func<Dictionary<int, SpawnOccupant>> getSpawnOccupants, Func<HashSet<int>> getDisabledSpawnPoints, bool showUnoccupiedSpawnpoints)
+			Action<MapPreviewWidget, MapPreview, MouseInput> onMouseDown, Func<Dictionary<int, SpawnOccupant>> getSpawnOccupants,
+			Func<HashSet<int>> getDisabledSpawnPoints, bool showUnoccupiedSpawnpoints)
 		{
 			var mapRepository = modData.Manifest.Get<WebServices>().MapRepository;
 
@@ -34,8 +35,9 @@ namespace OpenRA.Mods.Common.Widgets.Logic
 			{
 				available.IsVisible = () =>
 				{
-					var map = getMap();
+					var (map, serverStatus) = getMap();
-					return map.Status == MapStatus.Available && (!map.RulesLoaded || !map.InvalidCustomRules);
+					var isPlayable = (serverStatus & Session.MapStatus.Playable) == Session.MapStatus.Playable;
+					return map.Status == MapStatus.Available && isPlayable;
 				};
 
 				SetupWidgets(available, getMap, onMouseDown, getSpawnOccupants, getDisabledSpawnPoints, showUnoccupiedSpawnpoints);
@@ -46,17 +48,30 @@ namespace OpenRA.Mods.Common.Widgets.Logic
 			{
 				invalid.IsVisible = () =>
 				{
-					var map = getMap();
+					var (map, serverStatus) = getMap();
-					return map.Status == MapStatus.Available && map.InvalidCustomRules;
+					return map.Status == MapStatus.Available && (serverStatus & Session.MapStatus.Incompatible) != 0;
 				};
 
 				SetupWidgets(invalid, getMap, onMouseDown, getSpawnOccupants, getDisabledSpawnPoints, showUnoccupiedSpawnpoints);
 			}
 
+			var validating = widget.GetOrNull("MAP_VALIDATING");
+			if (validating != null)
+			{
+				validating.IsVisible = () =>
+				{
+					var (map, serverStatus) = getMap();
+					return map.Status == MapStatus.Available && (serverStatus & Session.MapStatus.Validating) != 0;
+				};
+
+				SetupWidgets(validating, getMap, onMouseDown, getSpawnOccupants, getDisabledSpawnPoints, showUnoccupiedSpawnpoints);
+			}
+
 			var download = widget.GetOrNull("MAP_DOWNLOADABLE");
 			if (download != null)
 			{
-				download.IsVisible = () => getMap().Status == MapStatus.DownloadAvailable;
+				download.IsVisible = () => getMap().Map.Status == MapStatus.DownloadAvailable;
+
 				SetupWidgets(download, getMap, onMouseDown, getSpawnOccupants, getDisabledSpawnPoints, showUnoccupiedSpawnpoints);
 
 				var install = download.GetOrNull<ButtonWidget>("MAP_INSTALL");
@@ -64,10 +79,8 @@ namespace OpenRA.Mods.Common.Widgets.Logic
 				{
 					install.OnClick = () =>
 					{
-						var map = getMap();
+						getMap().Map.Install(mapRepository, () =>
-						map.Install(mapRepository, () =>
 						{
-							map.PreloadRules();
 							if (orderManager != null)
 								Game.RunAfterTick(() => orderManager.IssueOrder(Order.Command("state {0}".F(Session.ClientState.NotReady))));
 						});
@@ -82,7 +95,7 @@ namespace OpenRA.Mods.Common.Widgets.Logic
 			{
 				progress.IsVisible = () =>
 				{
-					var map = getMap();
+					var (map, _) = getMap();
 					return map.Status != MapStatus.Available && map.Status != MapStatus.DownloadAvailable;
 				};
 
@@ -90,29 +103,36 @@ namespace OpenRA.Mods.Common.Widgets.Logic
 
 				var statusSearching = progress.GetOrNull("MAP_STATUS_SEARCHING");
 				if (statusSearching != null)
-					statusSearching.IsVisible = () => getMap().Status == MapStatus.Searching;
+				{
+					statusSearching.IsVisible = () =>
+					{
+						var (map, _) = getMap();
+						return map.Status == MapStatus.Searching;
+					};
+				}
 
 				var statusUnavailable = progress.GetOrNull("MAP_STATUS_UNAVAILABLE");
 				if (statusUnavailable != null)
 				{
 					statusUnavailable.IsVisible = () =>
 					{
-						var map = getMap();
+						var (map, _) = getMap();
 						return map.Status == MapStatus.Unavailable && map != MapCache.UnknownMap;
 					};
 				}
 
 				var statusError = progress.GetOrNull("MAP_STATUS_ERROR");
 				if (statusError != null)
-					statusError.IsVisible = () => getMap().Status == MapStatus.DownloadError;
+					statusError.IsVisible = () => getMap().Map.Status == MapStatus.DownloadError;
 
 				var statusDownloading = progress.GetOrNull<LabelWidget>("MAP_STATUS_DOWNLOADING");
 				if (statusDownloading != null)
 				{
-					statusDownloading.IsVisible = () => getMap().Status == MapStatus.Downloading;
+					statusDownloading.IsVisible = () => getMap().Map.Status == MapStatus.Downloading;
+
 					statusDownloading.GetText = () =>
 					{
-						var map = getMap();
+						var (map, _) = getMap();
 						if (map.DownloadBytes == 0)
 							return "Connecting...";
 
@@ -129,18 +149,17 @@ namespace OpenRA.Mods.Common.Widgets.Logic
 				{
 					retry.IsVisible = () =>
 					{
-						var map = getMap();
+						var (map, _) = getMap();
 						return (map.Status == MapStatus.DownloadError || map.Status == MapStatus.Unavailable) && map != MapCache.UnknownMap;
 					};
 
 					retry.OnClick = () =>
 					{
-						var map = getMap();
+						var (map, _) = getMap();
 						if (map.Status == MapStatus.DownloadError)
 						{
 							map.Install(mapRepository, () =>
 							{
-								map.PreloadRules();
 								if (orderManager != null)
 									Game.RunAfterTick(() => orderManager.IssueOrder(Order.Command("state {0}".F(Session.ClientState.NotReady))));
 							});
@@ -149,15 +168,15 @@ namespace OpenRA.Mods.Common.Widgets.Logic
 							modData.MapCache.QueryRemoteMapDetails(mapRepository, new[] { map.Uid });
 					};
 
-					retry.GetText = () => getMap().Status == MapStatus.DownloadError ? "Retry Install" : "Retry Search";
+					retry.GetText = () => getMap().Map.Status == MapStatus.DownloadError ? "Retry Install" : "Retry Search";
 				}
 
 				var progressbar = progress.GetOrNull<ProgressBarWidget>("MAP_PROGRESSBAR");
 				if (progressbar != null)
 				{
-					progressbar.IsIndeterminate = () => getMap().DownloadPercentage == 0;
+					progressbar.IsIndeterminate = () => getMap().Map.DownloadPercentage == 0;
-					progressbar.GetPercentage = () => getMap().DownloadPercentage;
+					progressbar.GetPercentage = () => getMap().Map.DownloadPercentage;
-					progressbar.IsVisible = () => getMap().Status == MapStatus.Downloading;
+					progressbar.IsVisible = () => getMap().Map.Status == MapStatus.Downloading;
 				}
 			}
 		}
@@ -171,12 +190,16 @@ namespace OpenRA.Mods.Common.Widgets.Logic
 			}
 		}
 
-		void SetupWidgets(Widget parent, Func<MapPreview> getMap,
+		void SetupWidgets(Widget parent,
-			Action<MapPreviewWidget, MapPreview, MouseInput> onMouseDown, Func<Dictionary<int, SpawnOccupant>> getSpawnOccupants, Func<HashSet<int>> getDisabledSpawnPoints, bool showUnoccupiedSpawnpoints)
+			Func<(MapPreview Map, Session.MapStatus Status)> getMap,
+			Action<MapPreviewWidget, MapPreview, MouseInput> onMouseDown,
+			Func<Dictionary<int, SpawnOccupant>> getSpawnOccupants,
+			Func<HashSet<int>> getDisabledSpawnPoints,
+			bool showUnoccupiedSpawnpoints)
 		{
 			var preview = parent.Get<MapPreviewWidget>("MAP_PREVIEW");
-			preview.Preview = () => getMap();
+			preview.Preview = () => getMap().Map;
-			preview.OnMouseDown = mi => onMouseDown(preview, getMap(), mi);
+			preview.OnMouseDown = mi => onMouseDown(preview, getMap().Map, mi);
 			preview.SpawnOccupants = getSpawnOccupants;
 			preview.DisabledSpawnPoints = getDisabledSpawnPoints;
 			preview.ShowUnoccupiedSpawnpoints = showUnoccupiedSpawnpoints;
@@ -184,18 +207,18 @@ namespace OpenRA.Mods.Common.Widgets.Logic
 			var titleLabel = parent.GetOrNull<LabelWithTooltipWidget>("MAP_TITLE");
 			if (titleLabel != null)
 			{
-				titleLabel.IsVisible = () => getMap() != MapCache.UnknownMap;
+				titleLabel.IsVisible = () => getMap().Map != MapCache.UnknownMap;
 				var font = Game.Renderer.Fonts[titleLabel.Font];
 				var title = new CachedTransform<MapPreview, string>(m => WidgetUtils.TruncateText(m.Title, titleLabel.Bounds.Width, font));
-				titleLabel.GetText = () => title.Update(getMap());
+				titleLabel.GetText = () => title.Update(getMap().Map);
-				titleLabel.GetTooltipText = () => getMap().Title;
+				titleLabel.GetTooltipText = () => getMap().Map.Title;
 			}
 
 			var typeLabel = parent.GetOrNull<LabelWidget>("MAP_TYPE");
 			if (typeLabel != null)
 			{
 				var type = new CachedTransform<MapPreview, string>(m => m.Categories.FirstOrDefault() ?? "");
-				typeLabel.GetText = () => type.Update(getMap());
+				typeLabel.GetText = () => type.Update(getMap().Map);
 			}
 
 			var authorLabel = parent.GetOrNull<LabelWidget>("MAP_AUTHOR");
@@ -204,7 +227,7 @@ namespace OpenRA.Mods.Common.Widgets.Logic
 				var font = Game.Renderer.Fonts[authorLabel.Font];
 				var author = new CachedTransform<MapPreview, string>(
 					m => WidgetUtils.TruncateText("Created by {0}".F(m.Author), authorLabel.Bounds.Width, font));
-				authorLabel.GetText = () => author.Update(getMap());
+				authorLabel.GetText = () => author.Update(getMap().Map);
 			}
 		}
 	}

OpenRA.Mods.Common/Widgets/Logic/MissionBrowserLogic.cs

@@ -139,19 +139,16 @@ namespace OpenRA.Mods.Common.Widgets.Logic
 			if (allPreviews.Any())
 				SelectMap(allPreviews.First());
 
-			// Preload map preview and rules to reduce jank
+			// Preload map preview to reduce jank
 			new Thread(() =>
 			{
 				foreach (var p in allPreviews)
-				{
 					p.GetMinimap();
-					p.PreloadRules();
-				}
 			}).Start();
 
 			var startButton = widget.Get<ButtonWidget>("STARTGAME_BUTTON");
 			startButton.OnClick = StartMissionClicked;
-			startButton.IsDisabled = () => selectedMap == null || selectedMap.InvalidCustomRules;
+			startButton.IsDisabled = () => selectedMap == null;
 
 			widget.Get<ButtonWidget>("BACK_BUTTON").OnClick = () =>
 			{
@@ -373,9 +370,6 @@ namespace OpenRA.Mods.Common.Widgets.Logic
 		{
 			StopVideo(videoPlayer);
 
-			if (selectedMap.InvalidCustomRules)
-				return;
-
 			var orders = new List<Order>();
 			if (difficulty != null)
 				orders.Add(Order.Command("option difficulty {0}".F(difficulty)));

OpenRA.Mods.Common/Widgets/Logic/ReplayBrowserLogic.cs

@@ -17,6 +17,7 @@ using System.Linq;
 using System.Threading;
 using System.Threading.Tasks;
 using OpenRA.FileFormats;
+using OpenRA.Network;
 using OpenRA.Primitives;
 using OpenRA.Traits;
 using OpenRA.Widgets;
@@ -93,7 +94,7 @@ namespace OpenRA.Mods.Common.Widgets.Logic
 			Ui.LoadWidget("MAP_PREVIEW", mapPreviewRoot, new WidgetArgs
 			{
 				{ "orderManager", null },
-				{ "getMap", (Func<MapPreview>)(() => map) },
+				{ "getMap", (Func<(MapPreview, Session.MapStatus)>)(() => (map, Session.MapStatus.Playable)) },
 				{ "onMouseDown",  (Action<MapPreviewWidget, MapPreview, MouseInput>)((preview, mapPreview, mi) => { }) },
 				{ "getSpawnOccupants", (Func<Dictionary<int, SpawnOccupant>>)(() => spawnOccupants.Update(selectedReplay)) },
 				{ "getDisabledSpawnPoints", (Func<HashSet<int>>)(() => disabledSpawnPoints.Update(selectedReplay)) },
@@ -623,13 +624,8 @@ namespace OpenRA.Mods.Common.Widgets.Logic
 
 			try
 			{
-				if (map.Status != MapStatus.Available)
+				if (map.Status == MapStatus.Unavailable && Game.Settings.Game.AllowDownloading)
-				{
+					modData.MapCache.QueryRemoteMapDetails(services.MapRepository, new[] { map.Uid });
-					if (map.Status == MapStatus.DownloadAvailable)
-						LoadMapPreviewRules(map);
-					else if (Game.Settings.Game.AllowDownloading)
-						modData.MapCache.QueryRemoteMapDetails(services.MapRepository, new[] { map.Uid }, LoadMapPreviewRules);
-				}
 
 				var players = replay.GameInfo.Players
 					.GroupBy(p => p.Team)
@@ -685,15 +681,6 @@ namespace OpenRA.Mods.Common.Widgets.Logic
 			}
 		}
 
-		void LoadMapPreviewRules(MapPreview map)
-		{
-			new Task(() =>
-			{
-				// Force map rules to be loaded on this background thread
-				map.PreloadRules();
-			}).Start();
-		}
-
 		void WatchReplay()
 		{
 			if (selectedReplay != null && ReplayUtils.PromptConfirmReplayCompatibility(selectedReplay))

launch-dedicated.cmd

@@ -16,12 +16,13 @@ set ProfileIDWhitelist=""
 set EnableSingleplayer=False
 set EnableSyncReports=False
 set EnableGeoIP=True
+set EnableLintChecks=True
 set ShareAnonymizedIPs=True
 
 set SupportDir=""
 
 :loop
 
-bin\OpenRA.Server.exe Engine.EngineDir=".." Game.Mod=%Mod% Server.Name=%Name% Server.ListenPort=%ListenPort% Server.AdvertiseOnline=%AdvertiseOnline% Server.EnableSingleplayer=%EnableSingleplayer% Server.Password=%Password% Server.RecordReplays=%RecordReplays% Server.RequireAuthentication=%RequireAuthentication% Server.ProfileIDBlacklist=%ProfileIDBlacklist% Server.ProfileIDWhitelist=%ProfileIDWhitelist% Server.EnableSyncReports=%EnableSyncReports% Server.EnableGeoIP=%EnableGeoIP% Server.ShareAnonymizedIPs=%ShareAnonymizedIPs% Engine.SupportDir=%SupportDir%
+bin\OpenRA.Server.exe Engine.EngineDir=".." Game.Mod=%Mod% Server.Name=%Name% Server.ListenPort=%ListenPort% Server.AdvertiseOnline=%AdvertiseOnline% Server.EnableSingleplayer=%EnableSingleplayer% Server.Password=%Password% Server.RecordReplays=%RecordReplays% Server.RequireAuthentication=%RequireAuthentication% Server.ProfileIDBlacklist=%ProfileIDBlacklist% Server.ProfileIDWhitelist=%ProfileIDWhitelist% Server.EnableSyncReports=%EnableSyncReports% Server.EnableGeoIP=%EnableGeoIP% Server.EnableLintChecks=%EnableLintChecks% Server.ShareAnonymizedIPs=%ShareAnonymizedIPs% Engine.SupportDir=%SupportDir%
 
 goto loop

launch-dedicated.sh

@@ -26,6 +26,7 @@ ProfileIDWhitelist="${ProfileIDWhitelist:-""}"
 EnableSingleplayer="${EnableSingleplayer:-"False"}"
 EnableSyncReports="${EnableSyncReports:-"False"}"
 EnableGeoIP="${EnableGeoIP:-"True"}"
+EnableLintChecks="${EnableLintChecks:-"True"}"
 ShareAnonymizedIPs="${ShareAnonymizedIPs:-"True"}"
 
 SupportDir="${SupportDir:-""}"
@@ -43,6 +44,7 @@ while true; do
      Server.ProfileIDWhitelist="$ProfileIDWhitelist" \
      Server.EnableSyncReports="$EnableSyncReports" \
      Server.EnableGeoIP="$EnableGeoIP" \
+     Server.EnableLintChecks="$EnableLintChecks" \
      Server.ShareAnonymizedIPs="$ShareAnonymizedIPs" \
      Engine.SupportDir="$SupportDir"
 done

mods/cnc/chrome/lobby-mappreview.yaml

@@ -77,6 +77,42 @@ Container@MAP_PREVIEW:
 					Font: Tiny
 					Align: Center
 					Text: with this version of OpenRA
+		Container@MAP_VALIDATING:
+			Width: PARENT_RIGHT
+			Height: PARENT_BOTTOM
+			Children:
+				Background@MAP_BG:
+					Width: PARENT_RIGHT
+					Height: 158
+					Background: panel-gray
+					Children:
+						MapPreview@MAP_PREVIEW:
+							X: 1
+							Y: 1
+							Width: PARENT_RIGHT - 2
+							Height: PARENT_BOTTOM - 2
+							TooltipContainer: TOOLTIP_CONTAINER
+				LabelWithTooltip@MAP_TITLE:
+					Y: 159
+					Width: PARENT_RIGHT
+					Height: 25
+					Font: Bold
+					Align: Center
+					TooltipContainer: TOOLTIP_CONTAINER
+					TooltipTemplate: SIMPLE_TOOLTIP
+				Label@MAP_STATUS_VALIDATING:
+					Y: 174
+					Width: PARENT_RIGHT
+					Height: 25
+					Font: Tiny
+					Align: Center
+					Text: Validating...
+					IgnoreMouseOver: true
+				ProgressBar@MAP_PROGRESSBAR:
+					Y: 194
+					Width: PARENT_RIGHT
+					Height: 25
+					Indeterminate: True
 		Container@MAP_DOWNLOADABLE:
 			Width: PARENT_RIGHT
 			Height: PARENT_BOTTOM

mods/common/chrome/lobby-mappreview.yaml

@@ -77,6 +77,42 @@ Container@MAP_PREVIEW:
 					Font: Tiny
 					Align: Center
 					Text: with this version of OpenRA
+		Container@MAP_VALIDATING:
+			Width: PARENT_RIGHT
+			Height: PARENT_BOTTOM
+			Children:
+				Background@MAP_BG:
+					Width: PARENT_RIGHT
+					Height: 158
+					Background: dialog3
+					Children:
+						MapPreview@MAP_PREVIEW:
+							X: 1
+							Y: 1
+							Width: PARENT_RIGHT - 2
+							Height: PARENT_BOTTOM - 2
+							TooltipContainer: TOOLTIP_CONTAINER
+				LabelWithTooltip@MAP_TITLE:
+					Y: 159
+					Width: PARENT_RIGHT
+					Height: 25
+					Font: Bold
+					Align: Center
+					TooltipContainer: TOOLTIP_CONTAINER
+					TooltipTemplate: SIMPLE_TOOLTIP
+				Label@MAP_STATUS_VALIDATING:
+					Y: 174
+					Width: PARENT_RIGHT
+					Height: 25
+					Font: Tiny
+					Align: Center
+					Text: Validating...
+					IgnoreMouseOver: true
+				ProgressBar@MAP_PROGRESSBAR:
+					Y: 194
+					Width: PARENT_RIGHT
+					Height: 25
+					Indeterminate: True
 		Container@MAP_DOWNLOADABLE:
 			Width: PARENT_RIGHT
 			Height: PARENT_BOTTOM