PurePosixPath subclass causing Mismatch between signature.. since 1.1.373

[davetapley]

1.1.354 was happy with code below (and works at run time), but I just bumped to 1.1.373 and I'm getting:

error: Mismatch between signature of __new__ and __init__ in class "Sensor"
    Signature of __init__ is "(*parts: str | PurePosixPath) -> None"
    Signature of __new__ is "(*args: StrPath, **kwargs: Unused) -> Sensor" (reportInconsistentConstructor)

Offending code:

from pathlib import PurePosixPath
from pathvalidate import Platform, sanitize_filepath

class Sensor(PurePosixPath):
    def __init__(self, *parts: str | PurePosixPath) -> None:
        parts_ = tuple(sanitize_filepath(str(p), platform=Platform.POSIX)
                       for p in parts)
        super(Sensor, self).__init__(*parts_)

I know there's been awkwardness around pathlib subclassing in the past, but I'm on Python 3.12.1 and I figured it had all been cleaned up. Any ideas? 🤔

[erictraut]

I presume that you have manually enabled the reportInconsistentConstructor check or enabled "strict" type checking mode in your configuration. This diagnostic check is not enabled by default. If you don't want errors of this type to be reported, you can turn it back off.

The purpose of this check is to report situations where the __new__ method and __init__ method for a class are inconsistent. That is the case in your example.

According to the typeshed stubs, the class PurePosixPath inherits a __new__ method from PurePath, and it is defined as:

    if sys.version_info >= (3, 12):
        def __new__(cls, *args: StrPath, **kwargs: Unused) -> Self: ...
    else:
        def __new__(cls, *args: StrPath) -> Self: ...

Since you're using Python 3.12, pyright will use the first of these two __new__ definitions.

If you want your __init__ method to be compatible, it would also need to accept positional parameters of type str | PathLike[str] and a **kwargs parameter.