diff -r ddbee2d0d634 -r bbc24c0753a0 mercurial/commands.py
--- a/mercurial/commands.py	Fri Apr 24 10:43:12 2009 +0200
+++ b/mercurial/commands.py	Wed Apr 22 00:55:32 2009 +0200
@@ -1306,7 +1306,7 @@
         heads = repo.heads(start, closed=closed)
     else:
         heads = []
-        visitedset = util.set()
+        visitedset = set()
         for branchrev in branchrevs:
             branch = repo[branchrev].branch()
             if branch in visitedset: