mercurial/commands.py

--- a/mercurial/commands.py	Tue Nov 13 08:41:56 2012 -0800
+++ b/mercurial/commands.py	Mon Nov 12 19:27:03 2012 +0200
@@ -2935,7 +2935,7 @@
     def matchlines(body):
         begin = 0
         linenum = 0
-        while True:
+        while True and begin < len(body):
             match = regexp.search(body, begin)
             if not match:
                 break