redefined-outer-name / W0621

Message emitted:

Redefining name %r from outer scope (line %s)

Description:

Used when a variable's name hides a name defined in an outer scope or except handler.

Problematic code:

count = 10


def count_it(count):  # [redefined-outer-name]
    for i in range(count):
        print(i)

Correct code:

count = 10


def count_it(limit):
    for i in range(limit):
        print(i)

Additional details:

A common issue is that this message is triggered when using pytest fixtures:

import pytest

@pytest.fixture
def setup():
    ...


def test_something(setup):  # [redefined-outer-name]
    ...

One solution to this problem is to explicitly name the fixture:

@pytest.fixture(name="setup")
def setup_fixture():
    ...

Alternatively pylint plugins like pylint-pytest can be used.

Created by the variables checker.