diff -r 9f56d462634c -r 0ec17613582c mercurial/encoding.py
--- a/mercurial/encoding.py	Sun May 28 14:02:14 2017 -0400
+++ b/mercurial/encoding.py	Sun May 28 13:27:29 2017 -0400
@@ -194,8 +194,8 @@
                    for k, v in os.environ.items())  # re-exports
 
 # How to treat ambiguous-width characters. Set to 'wide' to treat as wide.
-wide = (environ.get("HGENCODINGAMBIGUOUS", "narrow") == "wide"
-        and "WFA" or "WF")
+wide = _sysstr(environ.get("HGENCODINGAMBIGUOUS", "narrow") == "wide"
+               and "WFA" or "WF")
 
 def colwidth(s):
     "Find the column width of a string for display in the local encoding"