diff -r c94cdeeb586a -r 76f20fc8d54d mercurial/commands.py
--- a/mercurial/commands.py	Tue Oct 13 17:11:52 2015 -0400
+++ b/mercurial/commands.py	Tue Oct 13 17:12:12 2015 -0400
@@ -6515,8 +6515,7 @@
                            for r in op.records['changegroup']]
                 modheads = changegroup.combineresults(changes)
             else:
-                modheads = changegroup.addchangegroup(repo, gen, 'unbundle',
-                                                      'bundle:' + fname)
+                modheads = gen.apply(repo, 'unbundle', 'bundle:' + fname)
     finally:
         lock.release()