paul j3 added the comment: I just found a case where `dest` is `SUPPRESS` - the default subparsers setup.
_SubParsersAction(option_strings=[], dest='==SUPPRESS==', nargs='A...', ... If I make this Action 'required' (in the current distribution 'subparsers' are not required - there's a bug/issue for that) parser._actions[1].required=True and call the parser without the required subparser argument I should get an error message. In earlier versions this would have been a non specific, `error: too few arguments', but the new one tries to name the missing argument, e.g. program: error: the following arguments are required: choice But with SUPPRESS I get a further error as _parse_known_args tries to format this error message: C:\Users\paul\Miniconda3\lib\argparse.py in _parse_known_args(self, arg_strings, namespace) 1991 if required_actions: 1992 self.error(_('the following arguments are required: %s') % -> 1993 ', '.join(required_actions)) TypeError: sequence item 0: expected str instance, NoneType found (This error may have been reported elsewhere. This issue is the first one I found that deals with `dest=argparse.SUPPRESS`.) ---------- _______________________________________ Python tracker <rep...@bugs.python.org> <http://bugs.python.org/issue20430> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com