From 924c79b0ad06885d793d477bfc9d129da676d62b Mon Sep 17 00:00:00 2001
From: Paul Chote <pchote@users.noreply.github.com>
Date: Sun, 18 Jan 2026 22:38:24 +0000
Subject: [PATCH] Persist generated map across skirmish settings.

---
 OpenRA.Game/GameInformation.cs                 |  2 +-
 OpenRA.Game/Map/MapGenerationArgs.cs           |  8 ++++----
 OpenRA.Game/Network/GameSave.cs                |  2 +-
 .../ServerTraits/SkirmishLogic.cs              | 18 +++++++++++++++---
 .../Widgets/Logic/Lobby/LobbyLogic.cs          |  4 +++-
 5 files changed, 24 insertions(+), 10 deletions(-)

diff --git a/OpenRA.Game/GameInformation.cs b/OpenRA.Game/GameInformation.cs
index 04e9bbed66..7ff72430e6 100644
--- a/OpenRA.Game/GameInformation.cs
+++ b/OpenRA.Game/GameInformation.cs
@@ -115,7 +115,7 @@ namespace OpenRA
 				nodes.Add(new MiniYamlNode($"Player@{i}", FieldSaver.Save(Players[i])));
 
 			if (MapGenerationArgs != null)
-				nodes.Add(new MiniYamlNode("MapGenerationArgs", new MiniYaml("", MiniYaml.FromString(MapGenerationArgs.Serialize(), "MapGenerationArgs"))));
+				nodes.Add(new MiniYamlNode("MapGenerationArgs", new MiniYaml("", MapGenerationArgs.Serialize())));
 
 			return nodes.WriteToString();
 		}
diff --git a/OpenRA.Game/Map/MapGenerationArgs.cs b/OpenRA.Game/Map/MapGenerationArgs.cs
index 0d6e6b1d39..acfac1dbb1 100644
--- a/OpenRA.Game/Map/MapGenerationArgs.cs
+++ b/OpenRA.Game/Map/MapGenerationArgs.cs
@@ -41,10 +41,10 @@ namespace OpenRA
 			return yaml.NodeWithKey("Settings").Value;
 		}
 
-		public string Serialize()
+		public List<MiniYamlNode> Serialize()
 		{
-			return new List<MiniYamlNode>()
-			{
+			return
+			[
 				new("Uid", Uid),
 				new("Generator", Generator),
 				new("Tileset", Tileset),
@@ -52,7 +52,7 @@ namespace OpenRA
 				new("Settings", Settings),
 				new("Title", Title),
 				new("Author", Author)
-			}.WriteToString();
+			];
 		}
 	}
 }
diff --git a/OpenRA.Game/Network/GameSave.cs b/OpenRA.Game/Network/GameSave.cs
index d1a9b6889c..c2608ecc46 100644
--- a/OpenRA.Game/Network/GameSave.cs
+++ b/OpenRA.Game/Network/GameSave.cs
@@ -314,7 +314,7 @@ namespace OpenRA.Network
 					.ToList();
 				file.WriteLengthPrefixedString(Encoding.UTF8, slotClientNodes.WriteToString());
 
-				file.WriteLengthPrefixedString(Encoding.UTF8, MapGenerationArgs?.Serialize() ?? string.Empty);
+				file.WriteLengthPrefixedString(Encoding.UTF8, MapGenerationArgs?.Serialize().WriteToString() ?? string.Empty);
 
 				var traitDataOffset = file.Length;
 				file.Write(TraitDataMarker);
diff --git a/OpenRA.Mods.Common/ServerTraits/SkirmishLogic.cs b/OpenRA.Mods.Common/ServerTraits/SkirmishLogic.cs
index 9259b2abc0..e92e60685f 100644
--- a/OpenRA.Mods.Common/ServerTraits/SkirmishLogic.cs
+++ b/OpenRA.Mods.Common/ServerTraits/SkirmishLogic.cs
@@ -76,8 +76,19 @@ namespace OpenRA.Mods.Common.Server
 			// Only set players and options if the map is available
 			if (server.LobbyInfo.GlobalSettings.Map != mapNode.Value.Value)
 			{
-				var map = server.ModData.MapCache[mapNode.Value.Value];
-				if (map.Status != MapStatus.Available || !server.InterpretCommand($"map {map.Uid}", conn))
+				var preview = server.ModData.MapCache[mapNode.Value.Value];
+				if (preview.Status != MapStatus.Available)
+				{
+					if (mapNode.Value.Nodes.Length == 0)
+						return false;
+
+					var args = FieldLoader.Load<MapGenerationArgs>(mapNode.Value);
+					preview.UpdateFromGenerationArgs(args);
+					preview.Generate();
+					server.GeneratedMapData = mapNode.Value.Nodes.WriteToString();
+				}
+
+				if (!server.InterpretCommand($"map {preview.Uid}", conn))
 					return false;
 			}
 
@@ -157,9 +168,10 @@ namespace OpenRA.Mods.Common.Server
 				return;
 
 			var playerClient = server.LobbyInfo.NonBotClients.First();
+			var map = server.ModData.MapCache[server.LobbyInfo.GlobalSettings.Map];
 			var nodes = new List<MiniYamlNode>
 			{
-				new("Map", server.LobbyInfo.GlobalSettings.Map),
+				new("Map", server.LobbyInfo.GlobalSettings.Map, map.GenerationArgs?.Serialize() ?? []),
 				new("Options", new MiniYaml("", server.LobbyInfo.GlobalSettings.LobbyOptions
 					.Select(kv => new MiniYamlNode(kv.Key, kv.Value.Value)))),
 				new("Player", new SkirmishSlot(playerClient).ToYaml()),
diff --git a/OpenRA.Mods.Common/Widgets/Logic/Lobby/LobbyLogic.cs b/OpenRA.Mods.Common/Widgets/Logic/Lobby/LobbyLogic.cs
index 86b761cf58..a1f8cb2a3d 100644
--- a/OpenRA.Mods.Common/Widgets/Logic/Lobby/LobbyLogic.cs
+++ b/OpenRA.Mods.Common/Widgets/Logic/Lobby/LobbyLogic.cs
@@ -263,7 +263,7 @@ namespace OpenRA.Mods.Common.Widgets.Logic
 							return;
 
 						lastGeneratedMap = args;
-						orderManager.IssueOrder(Order.FromTargetString("GenerateMap", args.Serialize(), true));
+						orderManager.IssueOrder(Order.FromTargetString("GenerateMap", args.Serialize().WriteToString(), true));
 						orderManager.IssueOrder(Order.Command("map " + args.Uid));
 						Game.Settings.Server.Map = args.Uid;
 						Game.Settings.Save();
@@ -703,6 +703,8 @@ namespace OpenRA.Mods.Common.Widgets.Logic
 				return;
 
 			map = modData.MapCache[uid];
+			if (map.GenerationArgs != null)
+				lastGeneratedMap = map.GenerationArgs;
 
 			// Tell the server that we have the map
 			mapAvailable = map.Status == MapStatus.Available;