--- a/mercurial/localrepo.py	Sat Aug 05 02:00:09 2006 -0700
+++ b/mercurial/localrepo.py	Fri Aug 04 14:36:03 2006 -0700
@@ -292,6 +292,10 @@
         try:
             return self.tags()[key]
         except KeyError:
+            if key == '.':
+                key = self.dirstate.parents()[0]
+                if key == nullid:
+                    raise repo.RepoError(_("no revision checked out"))
             try:
                 return self.changelog.lookup(key)
             except: