Pylint does not discover a NoReturn method in certain cases to avoid "inconsistent-return-statements"

[e-gebes]

Bug description

from typing import NoReturn


def raise_function() -> NoReturn:
    raise RuntimeError


class MyClass:
    @staticmethod
    def raise_staticmethod() -> NoReturn:
        raise RuntimeError

    @classmethod
    def raise_classmethod(cls) -> NoReturn:
        raise RuntimeError

    def raise_instance_method(self) -> NoReturn:
        raise RuntimeError


def test_case_1():  # function -> OK
    if __name__:
        return None
    raise_function()


def test_case_2():  # staticmethod -> OK
    if __name__:
        return None
    MyClass.raise_staticmethod()


def test_case_3a():  # classmethod called on class -> OK
    if __name__:
        return None
    MyClass.raise_classmethod()


def test_case_3b():  # classmethod called on instance -> OK
    if __name__:
        return None
    MyClass().raise_classmethod()


def test_case_4a(obj):  # instance method called on anonymous obj -> fails
    if __name__:
        return None
    obj.raise_instance_method()


def test_case_4b(obj: MyClass):  # instance method called on type hinted obj -> fails
    if __name__:
        return None
    obj.raise_instance_method()


def test_case_4c():  # instance method called on ad-hoc created instance -> OK
    if __name__:
        return None
    MyClass().raise_instance_method()


def test_case_4d(obj):  # instance method called on class (avoiding the "self magic") -> fails
    if __name__:
        return None
    MyClass.raise_instance_method(obj)

Configuration

No response

Command used

pylint a.py

Pylint output

************* Module a
45:0: R1710: Either all return statements in a function should return an expression, or none of them should. (inconsistent-return-statements)
51:0: R1710: Either all return statements in a function should return an expression, or none of them should. (inconsistent-return-statements)
63:0: R1710: Either all return statements in a function should return an expression, or none of them should. (inconsistent-return-statements)

Expected behavior

This is a follow-up from: #1782 #4122 #4304

About the failing test cases 4a, 4b, 4d:

4a: seems hard to improve something about it - maybe Pylint could check all usages in the current project, and if all lead consistently to "NoReturn", suppress the warning. In my view checking occurrences alone might not be sensible to do, but wanted to mention the idea.

4b: would be nice if this worked, but is out of scope here, is related to type hint issues #9674 and #4813

4d: if Pylint gets case 4c right, I think it should also work with 4d. If this would be fixed, it would be an alternative to be used to avoid the inconsistent-return-statements warning before making use of type hints (4b) or more elaborate introspection (4a?) are available, which might not be soon.

Please think about improving Pylint to work also with case 4d.

Pylint version

pylint 2.17.7
astroid 2.15.8
Python 3.10.12 (main, Nov 20 2023, 15:14:05) [GCC 11.4.0]

OS / Environment

No response

Additional dependencies

No response

[Pierre-Sassoulas]

Thank you for opening the issue, it look like a duplicate of #9674

[e-gebes]

Thank you for opening the issue, it look like a duplicate of #9674

Thank you for the reply and link! I had a look and read into the discussion, also into #4813. I understand there is a general need to do underlying work to make Pylint better use type hints, and as well there is the general question: use more type hints like a type checker, or keep improving inference, or maybe a combination?

My issue report is related to type hints, in that sense it is a duplicate of the linked issues.

Anyway, I tried more things what works and what not. See my edited original report comment!

The type hints example (4b) I labelled as out of scope, I rephrased the title to make it independent of type hints. Meanwhile added case 4d might be relevant, please have a look again and consider re-opening the issue.

[jacobtylerwalls]

We can track this separately. The RefactoringChecker needs to call utils.is_terminating_func() somewhere.