--- a/mercurial/revlog.py	Tue May 16 09:35:38 2006 +0200
+++ b/mercurial/revlog.py	Tue May 16 11:07:56 2006 +0200
@@ -1137,7 +1137,7 @@
 
             for p in (p1, p2):
                 if not p in self.nodemap:
-                    raise RevlogError(_("unknown parent %s") % short(p1))
+                    raise RevlogError(_("unknown parent %s") % short(p))
 
             if not chain:
                 # retrieve the parent revision of the delta chain