From d3290195da55beae04d1bb86f811b6f8dd6b0663 Mon Sep 17 00:00:00 2001
From: Ben Harris <bjh21@bjh21.me.uk>
Date: Sun, 8 Jan 2023 12:34:57 +0000
Subject: [PATCH] Untangle: forbid descriptions that connect a node to itself

These cause an assertion failure in new_game(), so they should be
rejected by validate_desc().
---
 untangle.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/untangle.c b/untangle.c
index 1453afb..e849b5b 100644
--- a/untangle.c
+++ b/untangle.c
@@ -755,6 +755,8 @@ static const char *validate_desc(const game_params *params, const char *desc)
 		return "Expected ',' after number in game description";
 	    desc++;		       /* eat comma */
 	}
+        if (a == b)
+            return "Node linked to itself in game description";
     }
 
     return NULL;