--- a/mercurial/context.py	Sun Oct 06 19:25:18 2019 -0400
+++ b/mercurial/context.py	Mon Oct 07 00:04:04 2019 -0400
@@ -126,7 +126,7 @@
         deleted, unknown, ignored = s.deleted, s.unknown, s.ignored
         deletedset = set(deleted)
         d = mf1.diff(mf2, match=match, clean=listclean)
-        for fn, value in d.iteritems():
+        for fn, value in pycompat.iteritems(d):
             if fn in deletedset:
                 continue
             if value is None: