diff -r f1c9fafcbf46 -r 344e68882cd3 mercurial/ui.py
--- a/mercurial/ui.py	Sun Dec 18 01:54:36 2016 +0530
+++ b/mercurial/ui.py	Sun Dec 18 02:06:00 2016 +0530
@@ -143,7 +143,7 @@
             self.fin = util.stdin
 
             # shared read-only environment
-            self.environ = os.environ
+            self.environ = encoding.environ
 
             self.httppasswordmgrdb = urlreq.httppasswordmgrwithdefaultrealm()