diff -r 5fb3cb7266e5 -r df902fe3d79e mercurial/treediscovery.py
--- a/mercurial/treediscovery.py	Mon Jun 20 10:51:37 2011 +0200
+++ b/mercurial/treediscovery.py	Mon Jun 20 14:11:01 2011 +0200
@@ -49,7 +49,6 @@
     if not unknown:
         return list(base), [], list(heads)
 
-    heads = unknown
     req = set(unknown)
     reqcnt = 0