--- a/mercurial/dagutil.py	Fri Aug 19 10:05:23 2011 -0300
+++ b/mercurial/dagutil.py	Thu Aug 25 17:20:00 2011 +0200
@@ -260,7 +260,7 @@
             if isroot:
                 roots.append(rev)
             rev -= 1
-        self._walkfrom = rev - 1
+        self._walkfrom = rev
 
     def _getheads(self):
         self._walkto(nullrev)