diff -r 3999b74b6765 -r d5362671993b mercurial/configitems.py
--- a/mercurial/configitems.py	Sun Oct 08 21:41:37 2017 +0200
+++ b/mercurial/configitems.py	Sun Oct 08 22:06:35 2017 +0200
@@ -272,6 +272,9 @@
 coreconfigitem('experimental', 'graphshorten',
     default=False,
 )
+coreconfigitem('experimental', 'graphstyle.parent',
+    default=dynamicdefault,
+)
 coreconfigitem('experimental', 'hook-track-tags',
     default=False,
 )