From 08c8cf370ef7575a78988eb7d8f98c2a0bb92c63 Mon Sep 17 00:00:00 2001
From: Simon Tatham <anakin@pobox.com>
Date: Sun, 11 Sep 2005 11:57:24 +0000
Subject: [PATCH] Marginally greater robustness in the face of solve_game()
 failing to return an error message.

[originally from svn r6288]
---
 midend.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/midend.c b/midend.c
index 64edfd3..cc360b5 100644
--- a/midend.c
+++ b/midend.c
@@ -1167,12 +1167,15 @@ char *midend_solve(midend *me)
     if (me->statepos < 1)
 	return "No game set up to solve";   /* _shouldn't_ happen! */
 
-    msg = "Solve operation failed";    /* game _should_ overwrite on error */
+    msg = NULL;
     movestr = me->ourgame->solve(me->states[0].state,
 				 me->states[me->statepos-1].state,
 				 me->aux_info, &msg);
-    if (!movestr)
+    if (!movestr) {
+	if (!msg)
+	    msg = "Solve operation failed";   /* _shouldn't_ happen, but can */
 	return msg;
+    }
     s = me->ourgame->execute_move(me->states[me->statepos-1].state, movestr);
     assert(s);