diff -r 40ef3bf3e04a -r 3f522d2fa633 mercurial/patch.py
--- a/mercurial/patch.py	Thu Nov 05 15:06:35 2009 +0100
+++ b/mercurial/patch.py	Thu Nov 05 15:18:56 2009 +0100
@@ -1216,7 +1216,7 @@
     if opts is None:
         opts = mdiff.defaultopts
 
-    if not node1:
+    if not node1 and not node2:
         node1 = repo.dirstate.parents()[0]
 
     def lrugetfilectx():