diff -r b7a75b9a3386 -r 0407a51b9d8c mercurial/filemerge.py
--- a/mercurial/filemerge.py	Tue Jul 11 08:52:55 2017 -0700
+++ b/mercurial/filemerge.py	Fri Jul 14 14:22:40 2017 -0700
@@ -685,7 +685,7 @@
 
     r = 1
     try:
-        markerstyle = ui.config('ui', 'mergemarkers', 'basic')
+        markerstyle = ui.config('ui', 'mergemarkers')
         if not labels:
             labels = _defaultconflictlabels
         if markerstyle != 'basic':