pathlib.PureWindowsPath comparison results vary between Windows and Posix

[barneygale]

In #31691 I switched pathlib.PureWindowsPath comparisons to use os.path.normcase() rather than str.lower(). This is probably a mistake, as @eryksun points out:

The inconsistency is with ntpath.normcase() on Windows. It's probably for the best if the pure comparison methods revert to using str.lower() for the sake of consistency, not only with glob() and match(), but also with using PureWindowsPath on POSIX. Maybe platform-dependent comparisons could be implemented on Path.

On Windows, ntpath.normcase() is based on LCMapStringEx(). It turns out that this function implements a case mapping for some non-BMP characters. WinAPI CompareStringOrdinal(), on the other hand, has no case mapping for non-BMP characters, which is consistent with Microsoft's filesystems. Thus I'd prefer for a platform-dependent comparison to use CompareStringOrdinal() instead of LCMapStringEx().

Linked PRs

• GH-104947: Make pathlib.PureWindowsPath comparisons consistent across platforms #104948
• [3.12] GH-104947: Make pathlib.PureWindowsPath comparisons consistent across platforms (GH-104948) #104990

[barneygale]

Thanks for spotting this @eryksun. It's fixed in:

• ad0be36 / GH-104947: Make pathlib.PureWindowsPath comparisons consistent across platforms #104948
• eca102d / [3.12] GH-104947: Make pathlib.PureWindowsPath comparisons consistent across platforms (GH-104948) #104990

3.12 beta 2 will contain the fix.