diff -r 30e0dcd7c5ff -r a92ba36a1a9d mercurial/changegroup.py
--- a/mercurial/changegroup.py	Thu Oct 16 23:15:35 2014 -0700
+++ b/mercurial/changegroup.py	Wed Sep 24 21:24:06 2014 -0700
@@ -433,6 +433,8 @@
         # do nothing with basenode, it is implicitly the previous one in HG10
         return struct.pack(self.deltaheader, node, p1n, p2n, linknode)
 
+packermap = {'01': (cg1packer, cg1unpacker)}
+
 def _changegroupinfo(repo, nodes, source):
     if repo.ui.verbose or source == 'bundle':
         repo.ui.status(_("%d changesets found\n") % len(nodes))