False inconsistent-return-statements when using unittest.TestCase.fail

[bdrung]

Bug description

testcase.py:

# pylint: disable=missing-docstring
import unittest


class Test(unittest.TestCase):
    def helper(self, success: bool) -> str:
        if success:
            return "success"
        self.fail("It failed")

Configuration

Default configuration.

Command used

pylint testcase.py

Pylint output

************* Module testcase
testcase.py:6:4: R1710: Either all return statements in a function should return an expression, or none of them should. (inconsistent-return-statements)

Expected behavior

No complaint from pylint.

Pylint version

pylint 2.17.4
astroid 2.15.6
Python 3.11.4 (main, Jun  7 2023, 10:13:09) [GCC 12.3.0]

OS / Environment

Ubuntu 23.10 (mantic)

Additional dependencies

No response

[Pierre-Sassoulas]

Thank you for opening the issue, this is a duplicate of #4167

[bdrung]

Do I read #4167 correctly that this bug can be fixed by adding a NoReturn type hint to unittest.TestCase.fail (and use a pylint version that includes #4304)?

[bdrung]

The typeshed project already declare that unittest.TestCase.fail returns NoReturn: https://github.com/python/typeshed/blob/0d8a6bc2004b7b6d8335e35b017438125c305264/stdlib/unittest/case.pyi#L253

[Pierre-Sassoulas]

pylint do not take the pyi file into account in 2.17.5, this should be available in 3.0 alpha 7 hen we release it though #4987.