diff -r ff020ee5f06c -r d1901c4c8ec0 mercurial/mdiff.py
--- a/mercurial/mdiff.py	Thu Jan 12 12:05:23 2017 -0800
+++ b/mercurial/mdiff.py	Mon Jan 09 11:13:47 2017 -0800
@@ -52,6 +52,7 @@
         'nodates': False,
         'nobinary': False,
         'noprefix': False,
+        'index': 0,
         'ignorews': False,
         'ignorewsamount': False,
         'ignoreblanklines': False,