diff -r 346781c41597 -r ee9243715c59 mercurial/configitems.py
--- a/mercurial/configitems.py	Sat Oct 21 13:04:58 2017 +0900
+++ b/mercurial/configitems.py	Sat Oct 21 13:13:20 2017 +0900
@@ -106,7 +106,10 @@
 # Registering actual config items
 
 def getitemregister(configtable):
-    return functools.partial(_register, configtable)
+    f = functools.partial(_register, configtable)
+    # export pseudo enum as configitem.*
+    f.dynamicdefault = dynamicdefault
+    return f
 
 coreconfigitem = getitemregister(coreitems)