[issue4319] optparse and non-ascii help strings

[A.M. Kuchling]

New submission from A.M. Kuchling <lists at amk.ca>:

(copied from the Optik bug tracker)

Related bug:
http://www.mail-archive.com/python-bugs-list@python.org/msg07227.html

Hi all,

It seems to me that the workaround to the above bug in optparse.py versio
1.5.3 introduces a new bug when help strings are byte strings (as opposed
to unicode) containing non-ascii characters. Consider the following
script:

$ cat test.py
#!/usr/bin/env python
# -*- coding:latin-1 -*-

import optparse
parser = optparse.OptionParser()
parser.add_option("--test",help="This does not work: é")
parser.parse_args()

When called with "$ ./test.py --help", this script fails with the following
traceback:

$ ./test.py -h
Traceback (most recent call last):
File "./test.py", line 7, in <module>
parser.parse_args()
File "/usr/lib/python2.5/optparse.py", line 1385, in parse_args
stop = self._process_args(largs, rargs, values)
File "/usr/lib/python2.5/optparse.py", line 1429, in _process_args
self._process_short_opts(rargs, values)
File "/usr/lib/python2.5/optparse.py", line 1536, in _process_short_opts
option.process(opt, value, values, self)
File "/usr/lib/python2.5/optparse.py", line 782, in process
self.action, self.dest, opt, value, values, parser)
File "/usr/lib/python2.5/optparse.py", line 804, in take_action
parser.print_help()
File "/usr/lib/python2.5/optparse.py", line 1655, in print_help
file.write(self.format_help().encode(encoding, "replace"))
UnicodeDecodeError: 'ascii' codec can't decode byte 0xe9 in position 117:
ordinal not in range(128)

This behaviour can be reproduced with utf-8 encoded strings as well.

If I understand correctly, line 1655 of optparse.py only works if
format_help() returns an ascii byte string or a unicode string, but the
call to "encoding" fails when it is a byte string containing non-ascii
character.

I think this is either a bug and should be fixed, or very misleading (and
should be fixed too :).

I hope to have helped even a little.
Thanks for optparse, and keep up the good work!

Cheers,
Antoine

----------
components: Library (Lib)
messages: 75847
nosy: akuchling
severity: normal
status: open
title: optparse and non-ascii help strings
type: behavior
versions: Python 2.7

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<http://bugs.python.org/issue4319>
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