diff -r 5cd3e526ac37 -r ec80ae982689 mercurial/localrepo.py
--- a/mercurial/localrepo.py	Tue Jul 17 18:21:49 2012 +0200
+++ b/mercurial/localrepo.py	Tue Jul 17 16:16:17 2012 +0200
@@ -745,7 +745,7 @@
         # branch that ceased to exist may not be in newbranches because
         # newbranches is the set of candidate heads, which when you strip the
         # last commit in a branch will be the parent branch.
-        for branch in partial:
+        for branch in partial.keys():
             nodes = [head for head in partial[branch]
                      if self.changelog.hasnode(head)]
             if not nodes: