[issue38950] argparse uses "optional arguments" for "keyword arguments"

[Géry]

New submission from Géry <gery.ogam at gmail.com>:

The argparse module incorrectly uses the terms "optional arguments" for keyword arguments.

For instance this argument parser takes a required keyword argument and an optional positional argument, but classifies the former as an "optional argument" and the latter as a "positional argument":

>>> import argparse
>>> parser = argparse.ArgumentParser()
>>> parser.add_argument('--foo', required=True)
_StoreAction(option_strings=['--foo'], dest='foo', nargs=None, const=None, default=None, type=None, choices=None, help=None, metavar=None)
>>> parser.add_argument('bar', nargs='?')
_StoreAction(option_strings=[], dest='bar', nargs='?', const=None, default=None, type=None, choices=None, help=None, metavar=None)
>>> parser.parse_args(['-h'])
usage: [-h] --foo FOO [bar]

positional arguments:
  bar

optional arguments:
  -h, --help  show this help message and exit
  --foo FOO

Since the actual classification seems to distinguish positional from keyword arguments instead of required from optional arguments, I think that the "optional arguments:" section should be renamed to "keyword arguments:".

----------
components: Library (Lib)
messages: 357681
nosy: bethard, maggyero, rhettinger
priority: normal
severity: normal
status: open
title: argparse uses "optional arguments" for "keyword arguments"
type: enhancement
versions: Python 2.7, Python 3.5, Python 3.6, Python 3.7, Python 3.8, Python 3.9

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Python tracker <report at bugs.python.org>
<https://bugs.python.org/issue38950>
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