diff -r 6bbce5efc67b -r cc338115d3b2 mercurial/subrepo.py
--- a/mercurial/subrepo.py	Tue Aug 06 00:49:39 2013 +0200
+++ b/mercurial/subrepo.py	Wed Aug 21 22:34:04 2013 +0200
@@ -237,6 +237,7 @@
 
     # record merged .hgsubstate
     writestate(repo, sm)
+    return sm
 
 def _updateprompt(ui, sub, dirty, local, remote):
     if dirty: