Add case_sensitive argument to `pathlib.PurePath.match()`

[barneygale]

In #81079 we added a case_sensitive argument to pathlib.Path.glob() and rglob(). It would be good to have this functionality available in the closely-related PurePath.match() method. The rationale is much the same: this argument is useful when dealing with case-sensitive filesystems on Windows, and case-insensitive filesystems on Posix. Also, it would allow this method to be used from glob() to implement recursive globbing efficiently, which is important for #102613.

Linked PRs

• gh-104484: Add parameter @case_sensitive to pathlib.PurePath.match() function #104565

[barneygale]

I'd like to land #101398 before I start work on this.

[thirumurugan-git]

Hi @barneygale,
I believe it's a relatively simple problem that I can help fix. May I have the opportunity to work on it?

[thirumurugan-git]

@barneygale kindly review this PR

[barneygale]

Added in #104565 / dcdc90d. Thank you, @thirumurugan-git!

[eryksun]

It should be noted in the docs that Path.match() has changed in 3.12 to use re.IGNORECASE instead of normalizing the path and pattern with os.path.normcase(). On Windows, os.path.normcase() is based on the system's lowercase mapping, while re.IGNORECASE is based on Python's lowercase mapping. The two differ for 200 BMP characters and 260 non-BMP characters. Thus some patterns may match a path in 3.11 but not in 3.12, and vice versa.

[barneygale]

It used str.lower() in 3.11:

cpython/Lib/pathlib.py

Lines 189 to 190 in d1bfefd

	def casefold_parts(self, parts):
	return [p.lower() for p in parts]

[eryksun]

I lost track of changes in 3.12. I thought it always used normcase() for case folding in match() as well as the hash and comparison methods. Instead, this issue restores the use of str.lower() in match(). However, the hash and comparison methods will be inconsistent on Windows because they still use _str_normcase based on os.path.normcase(). Thus match() could be true while __eq__() is false, or vice versa, given component names that contain any of the 460 characters for which str.lower() and ntpath.normcase() are different.