[new rule] pylint W0133: Exception statement has no effect

[Taragolis]

This rule already requested into the #8674, however suggested replacement B018 can not handle all the cases.

For example this snippet do not violate any of B018 checks: https://play.ruff.rs/bef7e65b-09c6-4e8f-84e9-48a75be4e0b9

# w0133.py
from __future__ import annotations


def some_func(b: str, *, a: str | None = None, raise_an_error=True):
    if a:
        msg = "`a` is deprecated, consider to use `b` instead."
        if raise_an_error:
            msg = "Use `b` instead."
            ValueError(msg)
        DeprecationWarning(msg)
        b = a
    return b


class AwesomeClass:
    def __init__(self, b: str | None = None, **kwargs):
        if a := kwargs.pop("a", None):
            DeprecationWarning("`a` is deprecated, consider to use `b` instead.")
            if b and a != b:
                msg = f"Unable to resolve ambiguous values b={b!r}, a={a!r}."
                ValueError(msg)
            b = a
        self.b = b

    def abstract(self):
        NotImplementedError("abstract should be implemented")


ValueError("Foo")
DeprecationWarning("Bar")


if __name__ == "__main__":
    ValueError("Spam")
    DeprecationWarning("Egg")

In the other hand pylint rule W0133 catch all useless exceptions and warnings

❯ pipx run pylint --disable=all --enable="W0133" w0133.py
************* Module w0133
w0133.py:10:12: W0133: Exception statement has no effect (pointless-exception-statement)
w0133.py:11:8: W0133: Exception statement has no effect (pointless-exception-statement)
w0133.py:19:12: W0133: Exception statement has no effect (pointless-exception-statement)
w0133.py:22:16: W0133: Exception statement has no effect (pointless-exception-statement)
w0133.py:27:8: W0133: Exception statement has no effect (pointless-exception-statement)
w0133.py:30:0: W0133: Exception statement has no effect (pointless-exception-statement)
w0133.py:31:0: W0133: Exception statement has no effect (pointless-exception-statement)
w0133.py:35:4: W0133: Exception statement has no effect (pointless-exception-statement)
w0133.py:36:4: W0133: Exception statement has no effect (pointless-exception-statement)

It would be nice if it possible to have this rule as part of the ruff, this might help to found such a mistakes in codebase of pretty big projects.

[mikeleppane]

I could take a look at this. Let’s see, if this can be reasonably extended to the B018. Otherwise, this may require a separate rule?

[Taragolis]

If you ask me then I do not not have any preferences, so it could be either separate rule something like PLW0133 or extension of B018.

[zanieb]

Done in #10176