From 24b5033a0650ae1ba9682c6aac1e30c29cda5aec Mon Sep 17 00:00:00 2001
From: Rubidium <rubidium@openttd.org>
Date: Wed, 15 Mar 2023 20:59:58 +0100
Subject: [PATCH] Fix #10568: "can savegame be loaded check" failed in
 dedicated server

 * If loading fails, it usually returns SL_REINIT which doesn't trigger check
 * If savegame has NewGRFs, it complains NewGRFs are not allowed in intro game
---
 src/openttd.cpp           | 68 +++++++++++++++++++++++----------------
 src/video/dedicated_v.cpp | 11 -------
 2 files changed, 41 insertions(+), 38 deletions(-)

diff --git a/src/openttd.cpp b/src/openttd.cpp
index 010b366632..4a7806384a 100644
--- a/src/openttd.cpp
+++ b/src/openttd.cpp
@@ -969,37 +969,51 @@ bool SafeLoad(const std::string &filename, SaveLoadOperation fop, DetailedFileTy
 
 	_game_mode = newgm;
 
-	switch (lf == nullptr ? SaveOrLoad(filename, fop, dft, subdir) : LoadWithFilter(lf)) {
-		case SL_OK: return true;
-
-		case SL_REINIT:
-			if (_network_dedicated) {
-				/*
-				 * We need to reinit a network map...
-				 * We can't simply load the intro game here as that game has many
-				 * special cases which make clients desync immediately. So we fall
-				 * back to just generating a new game with the current settings.
-				 */
-				Debug(net, 0, "Loading game failed, so a new (random) game will be started");
-				MakeNewGame(false, true);
-				return false;
-			}
-			if (_network_server) {
-				/* We can't load the intro game as server, so disconnect first. */
-				NetworkDisconnect();
-			}
+	SaveOrLoadResult result = (lf == nullptr) ? SaveOrLoad(filename, fop, dft, subdir) : LoadWithFilter(lf);
+	if (result == SL_OK) return true;
+
+	if (_network_dedicated && ogm == GM_MENU) {
+		/*
+		 * If we are a dedicated server *and* we just were in the menu, then we
+		 * are loading the first savegame. If that fails, not starting the
+		 * server is a better reaction than starting the server with a newly
+		 * generated map as it is quite likely to be started from a script.
+		 */
+		Debug(net, 0, "Loading requested map failed; closing server.");
+		_exit_game = true;
+		return false;
+	}
 
-			switch (ogm) {
-				default:
-				case GM_MENU:   LoadIntroGame();      break;
-				case GM_EDITOR: MakeNewEditorWorld(); break;
-			}
-			return false;
+	if (result != SL_REINIT) {
+		_game_mode = ogm;
+		return false;
+	}
+
+	if (_network_dedicated) {
+		/*
+		 * If we are a dedicated server, have already loaded/started a game,
+		 * and then loading the savegame fails in a manner that we need to
+		 * reinitialize everything. We must not fall back into the menu mode
+		 * with the intro game, as that is unjoinable by clients. So there is
+		 * nothing else to do than start a new game, as it might have failed
+		 * trying to reload the originally loaded savegame/scenario.
+		 */
+		Debug(net, 0, "Loading game failed, so a new (random) game will be started");
+		MakeNewGame(false, true);
+		return false;
+	}
+
+	if (_network_server) {
+		/* We can't load the intro game as server, so disconnect first. */
+		NetworkDisconnect();
+	}
 
+	switch (ogm) {
 		default:
-			_game_mode = ogm;
-			return false;
+		case GM_MENU:   LoadIntroGame();      break;
+		case GM_EDITOR: MakeNewEditorWorld(); break;
 	}
+	return false;
 }
 
 void SwitchToMode(SwitchMode new_mode)
diff --git a/src/video/dedicated_v.cpp b/src/video/dedicated_v.cpp
index 259e7f7220..99dc5ee691 100644
--- a/src/video/dedicated_v.cpp
+++ b/src/video/dedicated_v.cpp
@@ -251,17 +251,6 @@ void VideoDriver_Dedicated::MainLoop()
 	/* If SwitchMode is SM_LOAD_GAME, it means that the user used the '-g' options */
 	if (_switch_mode != SM_LOAD_GAME) {
 		StartNewGameWithoutGUI(GENERATE_NEW_SEED);
-	} else {
-		/* First we need to test if the savegame can be loaded, else we will end up playing the
-		 *  intro game... */
-		if (SaveOrLoad(_file_to_saveload.name, _file_to_saveload.file_op, _file_to_saveload.detail_ftype, BASE_DIR) == SL_ERROR) {
-			/* Loading failed, pop out.. */
-			Debug(net, 0, "Loading requested map failed; closing server.");
-			return;
-		} else {
-			/* We can load this game, so go ahead */
-			_switch_mode = SM_LOAD_GAME;
-		}
 	}
 
 	this->is_game_threaded = false;