--- a/mercurial/commands.py	Fri Jul 25 13:27:06 2008 +0200
+++ b/mercurial/commands.py	Mon Jul 21 13:17:51 2008 +0200
@@ -1882,7 +1882,7 @@
 
     if not node:
         branch = repo.changectx(None).branch()
-        bheads = repo.branchheads()
+        bheads = repo.branchheads(branch)
         if len(bheads) > 2:
             raise util.Abort(_("branch '%s' has %d heads - "
                                "please merge with an explicit rev") %