diff -r d061ef1d781c -r 2114e44b08f6 mercurial/pure/mpatch.py
--- a/mercurial/pure/mpatch.py	Fri May 07 16:51:45 2010 -0400
+++ b/mercurial/pure/mpatch.py	Fri May 07 16:59:00 2010 -0500
@@ -112,7 +112,7 @@
         outlen += length
 
     if bin != binend:
-        raise Exception("patch cannot be decoded")
+        raise ValueError("patch cannot be decoded")
 
     outlen += orig - last
     return outlen