From 5c59ed2011905207bcd939a282513775d284dbd8 Mon Sep 17 00:00:00 2001
From: frosch <frosch@openttd.org>
Date: Sat, 12 Sep 2009 14:40:26 +0000
Subject: [PATCH] (svn r17510) -Fix [FS#3197]: When loading GRFConfigs from ini
 file, validate them wrt. duplicate GRF IDs.

---
 src/settings.cpp | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/src/settings.cpp b/src/settings.cpp
index 0e6a94aaca..312045a59a 100644
--- a/src/settings.cpp
+++ b/src/settings.cpp
@@ -1183,6 +1183,20 @@ static GRFConfig *GRFLoadConfig(IniFile *ini, const char *grpname, bool is_stati
 			continue;
 		}
 
+		/* Check for duplicate GRFID (will also check for duplicate filenames) */
+		bool duplicate = false;
+		for (const GRFConfig *gc = first; gc != NULL; gc = gc->next) {
+			if (gc->grfid == c->grfid) {
+				ShowInfoF("ini: ignoring  NewGRF '%s': duplicate GRF ID with '%s'", item->name, gc->filename);
+				duplicate = true;
+				break;
+			}
+		}
+		if (duplicate) {
+			ClearGRFConfig(&c);
+			continue;
+		}
+
 		/* Mark file as static to avoid saving in savegame. */
 		if (is_static) SetBit(c->flags, GCF_STATIC);