--- a/hgext/extdiff.py Mon Oct 15 09:43:34 2012 -0700
+++ b/hgext/extdiff.py Tue Oct 16 11:43:15 2012 -0700
@@ -329,3 +329,5 @@
cmdtable[cmd] = (save(cmd, path, diffopts),
cmdtable['extdiff'][1][1:],
_('hg %s [OPTION]... [FILE]...') % cmd)
+
+commands.inferrepo += " extdiff"