diff -r f5983805574e -r ead25aa27a43 mercurial/merge.py
--- a/mercurial/merge.py	Mon May 16 21:30:32 2016 +0000
+++ b/mercurial/merge.py	Mon May 16 21:30:53 2016 +0000
@@ -373,7 +373,7 @@
         """Write current state on disk in a version 1 file"""
         f = self._repo.vfs(self.statepathv1, 'w')
         irecords = iter(records)
-        lrecords = irecords.next()
+        lrecords = next(irecords)
         assert lrecords[0] == 'L'
         f.write(hex(self._local) + '\n')
         for rtype, data in irecords: