diff -r 2432b3227303 -r 5ef29e0dd418 mercurial/subrepo.py
--- a/mercurial/subrepo.py	Wed Feb 16 14:13:22 2011 -0600
+++ b/mercurial/subrepo.py	Wed Feb 16 11:53:48 2011 -0600
@@ -886,7 +886,7 @@
         if self.dirty():
             if self._gitstate() != revision:
                 dirty = self._gitstate() == self._state[1] or code != 0
-                if _updateprompt(self._ui, self, dirty, self._state[1], revision):
+                if _updateprompt(self._ui, self, dirty, self._state[1][:7], revision[:7]):
                     mergefunc()
         else:
             mergefunc()