unused-import for names used in class keyword arguments inside if expressions

[marmistrz]

Update 06/25/22: see comment for an example that still reproduces on 2.14.

Steps to reproduce

Lint the following code:

from abc import ABCMeta

class foo(meta=ABCMeta):
    pass

Current behavior

W:  1, 0: Unused ABCMeta imported from abc (unused-import)

Expected behavior

No unused-import error.

pylint --version output

pylint 1.7.2, 
astroid 1.5.3
Python 3.6.2 (default, Jul 20 2017, 03:52:27) 
[GCC 7.1.1 20170630]

[rogalski]

It's kind of corner case, we successfully lint code below, which is correct declaration of using metaclass:

from abc import ABCMeta

class foo(metaclass=ABCMeta):
    pass

[Wesitos]

Still present in version 1.8.2
I wouldn't consider this a corner case considering that python's 3.6 new __init_subclass__ method supports arbitrary keyword argument passing

[csabaszilveszter]

Present in 2.1.0 too..

pylint 2.1.0
astroid 2.0.2
Python 3.6.6 (default, Jun 28 2018, 04:42:43) 
[GCC 5.4.0 20160609]

The code:

from worklog_transfer.commons import Commons

class IpaUsersFile(metaclass=Commons.BaseSingleton):
    """Class for ipa user data."""
    ...

and then the results
Unused Commons imported from worklog_transfer.commons (unused-import)

[jonapich]

I'm also facing this, in an __init_subclass__ scenario. (pylint 2.2.2)

[PCManticore]

Thanks for the examples, folks. @jonapich Can you share a minimal reproduction example?

[Kane610]

This example will get

subclass.py:1:0: W0611: Unused TEXT imported from baseclass (unused-import)

file baseclass.py

TEXT = "string"
class baseclass:
    def __init_subclass__(cls, text, **kwargs):
        super().__init_subclass__(**kwargs)

file subclass.py

from baseclass import TEXT, baseclass
class subclass(baseclass, text=TEXT):
    pass

[douglas-raillard-arm]

Here is another variation on the same theme without using __init_subclass__, which also triggers:

test.py:2:0: W0611: Unused import os (unused-import)

import os

class Meta(type):
    def __new__(cls, name, bases, dct, *args, x=None, **kwargs):
        return super().__new__(cls, name, bases, dct, *args, **kwargs)

class C(metaclass=Meta, x=os):
    pass

[hippo91]

@douglas-raillard-arm thanks for this update.

[rsiemens]

I'm also seeing this when using an imported module in an expression in the class definition arguments list.

$ python -m pylint --version
pylint 2.13.9
astroid 2.11.5
Python 3.9.7 (default, Oct 22 2021, 07:42:57)
[Clang 12.0.5 (clang-1205.0.22.11)]

import django

class SomeMetaClass(type):
    pass

class MyClass(metaclass=type if django.VERSION >= (3, 2) else SomeMetaClass):
    pass

$ python -m pylint bug.py
************* Module bug
...
bug.py:1:0: W0611: Unused import django (unused-import)

[jacobtylerwalls]

Only the last example in #1630 (comment) seems to still reproduce on 2.14 dev, so I'm going to refocus the issue title.

[samskiter]

@jacobtylerwalls
Also seems to repro for an inner class definition :

from abc import ABCMeta
class Piece:
    class Connector(metaclass=ABCMeta):
        pass