diff -r 78a60daacea8 -r 2c364f7801c8 mercurial/subrepo.py
--- a/mercurial/subrepo.py	Wed May 07 00:08:20 2014 +0200
+++ b/mercurial/subrepo.py	Wed May 07 00:13:22 2014 +0200
@@ -205,12 +205,13 @@
                 sm[s] = r
             else:
                 debug(s, "both sides changed")
+                srepo = wctx.sub(s)
                 option = repo.ui.promptchoice(
                     _(' subrepository %s diverged (local revision: %s, '
                       'remote revision: %s)\n'
                       '(M)erge, keep (l)ocal or keep (r)emote?'
                       '$$ &Merge $$ &Local $$ &Remote')
-                    % (s, l[1][:12], r[1][:12]), 0)
+                    % (s, srepo.shortid(l[1]), srepo.shortid(r[1])), 0)
                 if option == 0:
                     wctx.sub(s).merge(r)
                     sm[s] = l