Fix #9706 PathLike with subtype

[nix010]

Change Summary

Fix #9706

Related issue number

Fix #9706

Checklist

• The pull request title is a good summary of the changes - it will be used in the changelog
• Unit tests for the changes exist
• Tests pass on CI
• Documentation reflects the changes where applicable
• My PR is ready to review, please add a comment including the phrase "please review" to assign reviewers

Selected Reviewer: @hramezani

[nix010]

please review

[codspeed-hq]

CodSpeed Performance Report

Merging #9764 will not alter performance

_{Comparing nix010:9706-fix-pathlike-with-sub-type (b5c87ec) with main (1e9873f)}

Summary

✅ 13 untouched benchmarks

[nix010]

Not sure if the change is align wiht what is expected from #9706 but made PR anyway to see if it on the right direction!

[sydney-runkle]

Hey @nix010,

Great start here. Left some general feedback + a few test requests!

[sydney-runkle]

Some ideas for simplification :)

[sydney-runkle]

What about:

orig_source_type: Any = get_origin(source_type) or source_type
if (source_type_args := get_args(source_type)) and source_type_args[0] not in {str, bytes, Any}:
    return None

if orig_source_type not in {
    os.PathLike,
    pathlib.Path,
    pathlib.PurePath,
    pathlib.PosixPath,
    pathlib.PurePosixPath,
    pathlib.PureWindowsPath,
}:
    return None

[nix010]

@sydney-runkle so there's a test case like test_string_import_callable which make source_type_args[0] a list and result in TypeError: unhashable type: 'list'.
So I just check it below.

is_path_like_subtype_invalid = (
        orig_source_type == os.PathLike
        and source_type_args
        and source_type_args[0]
        not in {
            str,
            bytes,
            Any,
        }
    )

    if is_path_like_subtype_invalid:
        return None 

[sydney-runkle]

@nix010,

I believe my suggestion above does the same...

[sydney-runkle]

What about:

construct_path = pathlib.PurePath if orig_source_type is os.PathLike else orig_source_type
constrained_schema = (
    core_schema.bytes_schema(**metadata) if source_type_args and source_type_args[0] is bytes 
    else core_schema.str_schema(**metadata)
)

def path_validator(input_value: str) -> os.PathLike[Any]:
    try:
        return construct_path(input_value)
    except TypeError as e:
        raise PydanticCustomError('path_type', 'Input is not a valid path') from e

[sydney-runkle]

I realize I've skipped the decoding here, one moment... trying to add back in with correct typing

[sydney-runkle]

I think this is type safe:

def path_validator(input_value: str | bytes) -> os.PathLike[str]:
    try:
        if source_type_args and source_type_args[0] is bytes:
            if isinstance(input_value, bytes):
                try:
                    input_value = input_value.decode()
                except UnicodeDecodeError as e:
                    raise PydanticCustomError('bytes_type', 'Input must be valid bytes') from e
            else:
                raise PydanticCustomError('bytes_type', 'Input must be bytes')
        elif not isinstance(input_value, str):
            raise PydanticCustomError('path_type', 'Input is not a valid path')
    
        return construct_path(input_value)
    except TypeError as e:
        raise PydanticCustomError('path_type', 'Input is not a valid path') from e

[sydney-runkle]

Hmm, I wonder if we want to change the JSON schema for these path types...

[nix010]

sure, what should we change them into ?

[sydney-runkle]

I feel like the type should be bytes for the byte_type path...

[sydney-runkle]

Honestly though, if someone complains we can fix this, I don't think it's super high priority and this gives us some flexibility to change it based on user experience.

[sydney-runkle]

Bc it's really a string once you populate the path

[sydney-runkle]

Great, thanks!!