Implement PEP 685

[brettcannon]

https://peps.python.org/pep-0685/

• Normalize extra comparisons
• Update requirements.Requirement.extras to raise a warning when names clash
• Update docs for packaging.utils.canonical_name()
• Expose utils.NormalizedName #495
• Add a metadata API #383
• Mark the PEP as "final"?

[brettcannon]

I think if we update:

packaging/packaging/markers.py

Lines 141 to 145 in ba12432

	def _coerce_parse_result(results: Union[ParseResults, List[Any]]) -> List[Any]:
	if isinstance(results, ParseResults):
	return [_coerce_parse_result(i) for i in results]
	else:
	return results

... to coerce extra comparisons immediately after parsing, then that's probably the easiest way to get the value normalized (for printing, writing, etc.). Then we have to worry about comparisons, which may be in:

packaging/packaging/markers.py

Lines 189 to 201 in ba12432

	def _eval_op(lhs: str, op: Op, rhs: str) -> bool:
	try:
	spec = Specifier("".join([op.serialize(), rhs]))
	except InvalidSpecifier:
	pass
	else:
	return spec.contains(lhs, prereleases=True)
	oper: Optional[Operator] = _operators.get(op.serialize())
	if oper is None:
	raise UndefinedComparison(f"Undefined {op!r} on {lhs!r} and {rhs!r}.")
	return oper(lhs, rhs)

... or:

packaging/packaging/markers.py

Lines 230 to 240 in ba12432

	elif isinstance(marker, tuple):
	lhs, op, rhs = marker
	if isinstance(lhs, Variable):
	lhs_value = _get_env(environment, lhs.value)
	rhs_value = rhs.value
	else:
	lhs_value = lhs.value
	rhs_value = _get_env(environment, rhs.value)
	groups[-1].append(_eval_op(lhs_value, op, rhs_value))

There's also separate work for requirements for the self.extras attribute:

packaging/packaging/requirements.py

Line 121 in ba12432

self.extras: Set[str] = set(req.extras.asList() if req.extras else [])

[brettcannon]

Thanks to @hroncok we have a PR to normalize the comparison. I have an in-progress PR on my local machine which normalizes for the string representation of markers.

[hroncok]

BTW I am sorry for not searching for this issue first. I should have and I have no idea why I haven't :(

[brettcannon]

BTW I am sorry for not searching for this issue first. I should have and I have no idea why I haven't :(

No worries! My in-progress PR isn't wasted regardless since the hardest part in it is normalizing at parse time for __str__().

[brettcannon]

Now that markers normalizes everything, I don't think requirements needs an update for extras. Any issues with those fields can (eventually) be handled by metadata.

[ofek]

Any update on this?

[brettcannon]

I think we can declare this as done as it's going to be for now. 😁 I just pushed the docs for packaging.utils.NormalizedName and packaging.utils.canonicalize_name(). I don't think this needs to wait for anything in packaging.metadata.

[ofek]

Nice! Any ETA for pip to upgrade its bundled copy of this?

[brettcannon]

Nice! Any ETA for pip to upgrade its bundled copy of this?

That's a @pradyunsg question.

[pradyunsg]

If we cut a packaging release early in this month (say, next week or so) then it'd be in pip 22.2 (due by end of month).

[ofek]

22.2 was released

[Julian]

@ofek not sure if that comment was meant to point this out too but this didn't make it into pip 22.2 right? Ostensibly because this repo needs a release first right @pradyunsg? Or am I misunderstanding still what's left for this one.

[Julian]

Ah, sorry to double post, but I see #569 is the ticket asking for a release, so this is still "blocked" on that on the pip side if I understand correctly.