diff -r 09f23b4f1be3 -r a80b8832720d mercurial/commands.py
--- a/mercurial/commands.py	Wed Aug 22 09:12:22 2018 +0800
+++ b/mercurial/commands.py	Sat Sep 01 17:37:52 2018 -0400
@@ -4563,7 +4563,7 @@
     if actioncount > 1:
         raise error.Abort(_("too many actions specified"))
     elif (actioncount == 0
-          and ui.config('commands', 'resolve.explicit-re-merge')):
+          and ui.configbool('commands', 'resolve.explicit-re-merge')):
         hint = _('use --mark, --unmark, --list or --re-merge')
         raise error.Abort(_('no action specified'), hint=hint)
     if pats and all: