# HG changeset patch
# User Gregory Szorc <gregory.szorc@gmail.com>
# Date 2018-02-12 02:47:19
# Node ID 9e47bfbeb7230317f9710768769779cbaadbb60c
# Parent  c02771617a70bb662a776306330ce4ef752f0718

py3: cast decode() argument to system string

The actual types here may be mixed due to string literals
and variables from other modules. So a cast is necessary.

Differential Revision: https://phab.mercurial-scm.org/D2166

diff --git a/mercurial/mail.py b/mercurial/mail.py
--- a/mercurial/mail.py
+++ b/mercurial/mail.py
@@ -206,7 +206,7 @@ def mimetextpatch(s, subtype='plain', di
         return mimetextqp(s, subtype, 'us-ascii')
     for charset in cs:
         try:
-            s.decode(charset)
+            s.decode(pycompat.sysstr(charset))
             return mimetextqp(s, subtype, codec2iana(charset))
         except UnicodeDecodeError:
             pass