diff -r 979c8ce9022d -r ef6215df2402 mercurial/help.py
--- a/mercurial/help.py	Thu Mar 22 17:08:25 2018 -0700
+++ b/mercurial/help.py	Fri Mar 23 11:20:49 2018 -0700
@@ -87,7 +87,7 @@
         lo = '--' + longopt
 
         if isinstance(default, fancyopts.customopt):
-            default = default.defaultvalue
+            default = default.getdefaultvalue()
         if default and not callable(default):
             # default is of unknown type, and in Python 2 we abused
             # the %s-shows-repr property to handle integers etc. To