diff --git a/mercurial/hg.py b/mercurial/hg.py
--- a/mercurial/hg.py
+++ b/mercurial/hg.py
@@ -110,7 +110,7 @@ class changelog(revlog):
 
     def extract(self, text):
         if not text:
-            return (nullid, "", 0, [], "")
+            return (nullid, "", "0", [], "")
         last = text.index("\n\n")
         desc = text[last + 2:]
         l = text[:last].splitlines()