--- a/mercurial/mail.py Thu Dec 05 16:18:44 2019 -0500 +++ b/mercurial/mail.py Mon Dec 02 14:44:26 2019 +0100 @@ -197,7 +197,7 @@ raise error.Abort( b'%s %s' % ( - os.path.basename(program.split(None, 1)[0]), + os.path.basename(procutil.shellsplit(program)[0]), procutil.explainexit(ret), ) )