paul j3 added the comment: On a related point, the 'action.required' value is set differently for '?' and '*' positionals.
if kwargs.get('nargs') not in [OPTIONAL, ZERO_OR_MORE]: kwargs['required'] = True if kwargs.get('nargs') == ZERO_OR_MORE and 'default' not in kwargs: kwargs['required'] = True OPTIONAL is always not required, ZERO_OR_MORE is not required if it has a default. But for reasons discussed here, that 'required' value makes little difference. `parse_args` checks that all 'required' arguments have been seen, but a ZERO_OR_MORE positional is always seen (i.e. it matches an empty string). Usage formatting always uses '[%s [%s ...]]' with ZERO_OR_MORE, regardless of the 'required' attribute. The only place where this 'required' value seems to matter is when adding such an argument to a mutually exclusive group. But if an unused '*' positional is going to get a '[]' value anyways, why should it be excluded from such a use? If I remove the if kwargs.get('nargs') == ZERO_OR_MORE and 'default' not in kwargs: test, test_argparse.py still runs fine. http://bugs.python.org/issue18943 is a possibly related issue, involving a 'is not action.default' test in a mutually exclusive group. ---------- _______________________________________ Python tracker <rep...@bugs.python.org> <http://bugs.python.org/issue16878> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com