diff -r fecfea658127 -r 596510cd2b12 mercurial/cext/parsers.c
--- a/mercurial/cext/parsers.c	Fri Oct 01 08:44:56 2021 -0700
+++ b/mercurial/cext/parsers.c	Thu Sep 30 18:06:34 2021 +0200
@@ -71,7 +71,7 @@
 	clean_p2 = 0;
 	possibly_dirty = 0;
 	parentfiledata = Py_None;
-	if (!PyArg_ParseTupleAndKeywords(args, kwds, "iiiiiiiO", keywords_name,
+	if (!PyArg_ParseTupleAndKeywords(args, kwds, "|iiiiiiiO", keywords_name,
 	                                 &wc_tracked, &p1_tracked, &p2_tracked,
 	                                 &merged, &clean_p1, &clean_p2,
 	                                 &possibly_dirty, &parentfiledata