Improve types and bytes usage of pathlib

[sobolevn]

Notes:

• link_to is removed in 3.12: https://github.com/python/cpython/blob/3.11/Lib/pathlib.py#L1222-L1225
• samefile uses the same args as Path.__new__

Source: https://github.com/python/cpython/blob/main/Lib/pathlib.py
Refs #9006

[srittau]

This just calls other_path.stat(), which should also work with Path[bytes]. In case it's not a Path, it's passed on to os.stat(), which uses int | StrOrBytesPath. I therefore think the following would be correct:

Suggested change

	def samefile(self, other_path: StrPath) -> bool: ...
	def samefile(self, other_path: StrOrBytesPath | int) -> bool: ...

[AlexWaygood]

Path[bytes] isn't a thing — Path isn't a generic class. pathlib only makes promises to work with string paths, unlike os.path or functions in os

[srittau]

I always mix up Path and PathLike. The annotation should be correct nevertheless.

[sobolevn]

Here' how this method is implemented:

    def samefile(self, other_path):
        st = self.stat()
        try:
            other_st = other_path.stat()
        except AttributeError:
            other_st = self.__class__(other_path).stat()
        return os.path.samestat(st, other_st)

So, other_path can either be:

• Something with .stat() method (assuming Path, it can be a new protocol, but I don't think it is worth it right now)
• Something that self.__class__.__new__ accepts: StrPath (== str | PathLike[str])

But, Path is a part of StrPath, because Path is PathLike[str].
That's why StrPath seems correct to me. Am I missing something?

[srittau]

Ah interesting, I was looking at the 3.9 version of the implementation:

https://github.com/python/cpython/blob/b43496c01a554cf41ae654a0379efae18609ad39/Lib/pathlib.py#L1145-L1154

    def samefile(self, other_path):
        """Return whether other_path is the same or not as this file
        (as returned by os.path.samefile()).
        """
        st = self.stat()
        try:
            other_st = other_path.stat()
        except AttributeError:
            other_st = self._accessor.stat(other_path)
        return os.path.samestat(st, other_st)

No need to version guard this. Let's just use the latest version (yours).

[github-actions]

Diff from mypy_primer, showing the effect of this PR on open source code:

bandersnatch (https://github.com/pypa/bandersnatch)
+ src/bandersnatch_storage_plugins/swift.py: note: In member "write_bytes" of class "SwiftPath":
+ src/bandersnatch_storage_plugins/swift.py:408: error: Signature of "write_bytes" incompatible with supertype "Path"
+ src/bandersnatch_storage_plugins/swift.py:408: note:      Superclass:
+ src/bandersnatch_storage_plugins/swift.py:408: note:          def write_bytes(self, data: Union[bytes, Union[bytearray, memoryview, array[Any], mmap, _CData, PickleBuffer]]) -> int
+ src/bandersnatch_storage_plugins/swift.py:408: note:      Subclass:
+ src/bandersnatch_storage_plugins/swift.py:408: note:          def write_bytes(self, contents: bytes, encoding: Optional[str] = ..., errors: Optional[str] = ...) -> int