Using Argparse.remainder At Beginning Of Parser / Sub Parser

I want to implement an arg parser that allows me to run unittests as one of the sub commands, blindly passing the arguments on to unittest.main(). e.g., $ foo.py unittest [args to

Solution 1:

Looks like the same issue discussed in http://bugs.python.org/issue17050, argparse.REMAINDER doesn't work as first argument

My deduction from 4 years ago still holds - the -blah is being classed as an optional's flag even before REMAINDER has a chance to act. '--' is parsed earlier, but ... is, in a sense just a generalization of '*'. And not a widely used one. For what it's worth the 'subparsers' Action has a nargs='+...' value (argparse.PARSER) - it's like REMAINDER except it requires at least one string, the 'cmd'.

The possible fix in http://bugs.python.org/issue9334 has not been acted on. So you either need to handle the '-blah' by itself, or use '--'. parse_known_args might also work in your case.

Solution 2:

As noted, the existing behavior is bad. One workaround is to implement a simple ArgumentParser subclass and use that for your subparser:

classSubcommandParser(argparse.ArgumentParser):
    """This subparser puts all remaining arguments in args attribute of namespace"""defparse_known_args(self, args=None, namespace=None):
        if namespace isNone:
            namespace = argparse.Namespace()
        setattr(namespace, 'args', args)
        return namespace, []

...

p.add_subparsers(dest='cmd', parser_class=SubcommandParser)