E0606: detect validation done in external function about pylint HOT 6 CLOSED

Yep. Or slightly more expressively typing.assert_never(suffix) in case it's ever reached at runtime to see what it was called with.

from pylint.

I think you can import it from typing_extensions, although I haven't tried it myself.

from pylint.

A potential workaround would be to explicitly mark modified will be set using some kind of asserts mechanism or comment that exists in the Typescript language (see here).

This what we've decided to support. Since pylint 3.2.1 you can use from typing import assert_never to assert exhaustiveness.

Will add your example to the docs 👍

from pylint.

@jacobtylerwalls Thanks for the fast response.

To clarify, you'd recommend a pattern like this one:

    if suffix == "d":
        modifier = f"-{number} days"
    elif suffix == "w":
        modifier = f"-{number * 7} days"
    elif suffix == "y":
        modifier = f"-{number} years"
    else:
        typing.assert_never()

from pylint.

Yep. Or slightly more expressively typing.assert_never(suffix) in case it's ever reached at runtime to see what it was called with.

Great. Thank you. 😊🙏

Feel free to close this.

from pylint.

@jacobtylerwalls Small follow-up: how do I do this in a backwards compatible way, so it also works on Python 3.8, 3.9, and 3.10? Something like this?

try:
    from typing import assert_never
except ImportError:
    # backwards compatability with Python 3.8, 3.9, 3.10
    def assert_never(arg: NoReturn, /) -> NoReturn:
        """Assert line is unreachable."""
        raise AssertionError(arg)

from pylint.