374     def lookup(self, key):

   374     def lookup(self, key):

   375         if key == '.':

   375         if key == '.':

   376             key = self.dirstate.parents()[0]

   376             key = self.dirstate.parents()[0]

   377             if key == nullid:

   377             if key == nullid:

   378                 raise repo.RepoError(_("no revision checked out"))

   378                 raise repo.RepoError(_("no revision checked out"))

   379         n = self.changelog._match(key)

   381         n = self.changelog._match(key)

   380         if n:

   382         if n:

   381             return n

   383             return n

   382         if key in self.tags():

   384         if key in self.tags():

   383             return self.tags()[key]

   385             return self.tags()[key]