--- a/mercurial/pure/diffhelpers.py	Sat Dec 12 13:34:55 2015 -0500
+++ b/mercurial/pure/diffhelpers.py	Sat Dec 12 13:35:41 2015 -0500
@@ -5,6 +5,8 @@
 # This software may be used and distributed according to the terms of the
 # GNU General Public License version 2 or any later version.
 
+from __future__ import absolute_import
+
 def addlines(fp, hunk, lena, lenb, a, b):
     while True:
         todoa = lena - len(a)