broken-noreturn / E6004

Message emitted:

'NoReturn' inside compound types is broken in 3.7.0 / 3.7.1

Description:

``typing.NoReturn`` inside compound types is broken in Python 3.7.0 and 3.7.1. If not dependent on runtime introspection, use string annotation instead. E.g. ``Callable[..., 'NoReturn']``. https://bugs.python.org/issue34921

Problematic code:

from typing import NoReturn, Union


def exploding_apple(apple) -> Union[None, NoReturn]:  # [broken-noreturn]
    print(f"{apple} is about to explode")

Correct code:

from typing import NoReturn


def exploding_apple(apple) -> NoReturn:
    print(f"{apple} is about to explode")
    raise Exception("{apple} exploded !")

Configuration file:

[main]
py-version=3.7
load-plugins=pylint.extensions.typing

Note

This message is emitted by the optional 'typing' checker, which requires the pylint.extensions.typing plugin to be loaded.

Created by the typing checker.