diff -r 2c37f9dabc32 -r f4433f2713d0 mercurial/encoding.py
--- a/mercurial/encoding.py	Sun Apr 23 14:47:52 2017 +0900
+++ b/mercurial/encoding.py	Sun Apr 23 12:59:42 2017 +0900
@@ -24,6 +24,7 @@
 
 charencode = policy.importmod(r'charencode')
 
+isasciistr = charencode.isasciistr
 asciilower = charencode.asciilower
 asciiupper = charencode.asciiupper
 _jsonescapeu8fast = charencode.jsonescapeu8fast