--- a/mercurial/revlog.py	Sun Oct 29 14:18:55 2006 +0100
+++ b/mercurial/revlog.py	Sun Oct 29 14:41:14 2006 +0100
@@ -500,6 +500,8 @@
 
     def size(self, rev):
         """return the length of the uncompressed text for a given revision"""
+        if rev == nullrev:
+            return 0
         l = -1
         if self.version != REVLOGV0:
             l = self.index[rev][2]