New check: manually accessing ``sys.argv`` value using indexes or range

[Pierre-Sassoulas]

If sys.argv is accessed directly it means you're not going to have the same level of support for errors than a dedicated library, and argparse is such a lib that is a builtin lib since python 3.2.

Originally posted by @Pierre-Sassoulas in #7710 (comment)

[nickdrozd]

This means unconditionally flagging any use of sys.argv and suggesting argparse instead?

[DanielNoord]

This very arbitrary and something that I would normally advise to make as a plug-in.

As a hack you could also use suggested-module with a non sensical replacement value.

[Pierre-Sassoulas]

Yes, it's clearly an optional extension candidate.

any use of sys.argv and suggesting argparse instead?

Not sys.argv alone, but any access of sys.argv using indexes or range, like my_arg = sys.argv[2], a, b, c = sys.argv[1:]. (and suggest 'argparse or another arg parsing library')

As a hack you could also use suggested-module with a non sensical replacement value.

I did not understand that part, I don't think we have a suggested-module option ?

[DanielNoord]

--preferred-modules 😄

https://pylint.pycqa.org/en/latest/user_guide/messages/warning/preferred-module.html

[Pierre-Sassoulas]

I liked the idea but preferred-module is checking at import time so this can't work atm:

[IMPORTS]
preferred-modules=json:ujson,re:regex,sys.argv:argparse;

"""Test preferred modules."""
# pylint: disable=unused-import

import json  # [preferred-module]
import sys
from re import search  # [preferred-module]

print(sys.argv[1:3])  # [preferred-module] <= not raised 

[DanielNoord]

Ah, I misremembered #8186