version: fix local label comparison

[abn]

Prior to this change, local label comparison was inconsistent with PEP 440. This change ensures that the local version label is checked for equivalence using a strict string equality comparison.

Resolves: python-poetry/poetry#4729

[sonarcloud]

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[radoering]

I don't think that's completely correct yet. PEP440 says:

"Comparison and ordering of local versions considers each segment of the local version (divided by a .) separately. If a segment consists entirely of ASCII digits then that section should be considered an integer for comparison purposes and if a segment contains any ASCII letters then that segment is compared lexicographically with case insensitivity. When comparing a numeric and lexicographic segment, the numeric section always compares as greater than the lexicographic segment. Additionally a local version with a great number of segments will always compare as greater than a local version with fewer segments, as long as the shorter local version’s segments match the beginning of the longer local version’s segments exactly."

It seems that comparing local version segments is already prepared here:

poetry-core/src/poetry/core/version/pep440/version.py

Lines 108 to 125 in dfd1b39

	_local: tuple[tuple[int, int | str], ...]
	if self.local is None:
	# Versions without a local segment should sort before those with one.
	_local = ((NegativeInfinity(), ""),)
	else:
	# Versions with a local segment need that segment parsed to implement
	# the sorting rules in PEP440.
	# - Alpha numeric segments sort before numeric segments
	# - Alpha numeric segments sort lexicographically
	# - Numeric segments sort numerically
	# - Shorter versions sort before longer versions when the prefixes
	# match exactly
	assert isinstance(self.local, tuple)
	_local = tuple(
	# We typecast strings that are integers so that they can be compared
	(int(i), "") if str(i).isnumeric() else (NegativeInfinity(), i)
	for i in self.local
	)

[radoering]

Duplicated line.

Maybe, it's worth adding assert not v.allows(Version.parse("1.2.3")) since that's new.

[radoering]

That's not completely correct. It actually has to be something like self._min.local < other.local. (However, this falls too short.)

[abn]

IIRC, local labels are to be treated as exact strings, so they should not be ordered when comparing.

[abn]

🤣

[radoering]

Yeah, it might not be suitable for stuff like 1.10.0+cu113 and 1.10.0+cpu but that's what PEP440 says.

[radoering]

Same as above.

[dimbleby]

python-poetry/poetry#5791 (comment)