--- a/mercurial/wireproto.py	Tue Apr 01 14:13:34 2014 -0700
+++ b/mercurial/wireproto.py	Tue Apr 01 14:25:03 2014 -0700
@@ -585,7 +585,7 @@
 def changegroupsubset(repo, proto, bases, heads):
     bases = decodelist(bases)
     heads = decodelist(heads)
-    cg = repo.changegroupsubset(bases, heads, 'serve')
+    cg = changegroupmod.changegroupsubset(repo, bases, heads, 'serve')
     return streamres(proto.groupchunks(cg))
 
 @wireprotocommand('debugwireargs', 'one two *')