diff -r 0ae35296fbf4 -r 7178f6fedb9d mercurial/cmdutil.py
--- a/mercurial/cmdutil.py	Thu Oct 07 18:24:29 2010 -0500
+++ b/mercurial/cmdutil.py	Fri Oct 08 14:02:23 2010 -0500
@@ -111,7 +111,7 @@
         limit = None
     return limit
 
-def revsingle(repo, revspec, default=None):
+def revsingle(repo, revspec, default='.'):
     if not revspec:
         return repo[default]