diff -r c0d0fd87ba7c -r bbd240f81ac5 mercurial/mail.py
--- a/mercurial/mail.py	Sat Apr 07 21:21:03 2018 +0900
+++ b/mercurial/mail.py	Sat Apr 07 21:23:42 2018 +0900
@@ -150,7 +150,7 @@
     if ret:
         raise error.Abort('%s %s' % (
             os.path.basename(program.split(None, 1)[0]),
-            procutil.explainexit(ret)[0]))
+            procutil.explainexit(ret)))
 
 def _mbox(mbox, sender, recipients, msg):
     '''write mails to mbox'''