unused-import when readline is imported to enhance input()

[michalfabik]

Bug description

#pylint: disable=missing-docstring

import readline

input()

Command used

pylint-3 a.py

Pylint output

************* Module a
a.py:4:0: W0611: Unused import readline (unused-import)

------------------------------------------------------------------
Your code has been rated at 5.00/10 (previous run: 5.00/10, +0.00)

Expected behavior

--------------------------------------------------------------------
Your code has been rated at 10.00/10 (previous run: 10.00/10, +0.00)  

"If the readline module was loaded, then input() will use it to provide elaborate line editing and history features." (https://docs.python.org/3/library/functions.html?highlight=input#input)

Pylint version

$ pylint-3 --version
pylint 2.14.4
astroid 2.12.14
Python 3.11.2 (main, Feb  8 2023, 00:00:00) [GCC 12.2.1 20221121 (Red Hat 12.2.1-4)]
$

OS / Environment

Fedora 37

[Pierre-Sassoulas]

Thank you for opening the issue. I don't think we have a mechanism for import used by function with side effects. It's probably a warning that should be disabled because "fixing" it in pylint cannot be done reasonably fast at this point. Also I don't have any other examples of such side effects based on import in mind that could justify to do the work to handle this generically. Waiting for other maintainers opinion but I'm considering closing as "won't fix".

[DanielNoord]

I also think this is hard to code, on the other hand this is the stdlib so should be "fixed" in pylint rather than a plugin.

[Pierre-Sassoulas]

It's true that it's in the stdlib so we should do something about it (probably). Without checking the full code of input() and detecting side effects (too much work clearly, and performance would be awful) we could create an option with a list of function that have side effect and the import it impacts (?).