--- a/hgext/transplant.py	Wed Feb 14 17:40:51 2018 +0530
+++ b/hgext/transplant.py	Wed Feb 14 17:41:27 2018 +0530
@@ -274,7 +274,7 @@
                                     },
                            onerr=error.Abort, errprefix=_('filter failed'),
                            blockedtag='transplant_filter')
-            user, date, msg = self.parselog(file(headerfile))[1:4]
+            user, date, msg = self.parselog(open(headerfile, 'rb'))[1:4]
         finally:
             os.unlink(headerfile)