22.0: The new requirement parser doesn't handle unnormalized specifiers

[frostming]

from packaging.specifiers import SpecifierSet
from packaging.requirements import Requirement

s = SpecifierSet('>=1.0-alpha')  # success
"1.0a0" in s  # True

r = Requirement('foo>=1.0-alpha')  # Error

Ideally, we should make them consistent.

[hroncok]

For the record, Requirement('foo>=1.0-alpha') worked with packaging 21 (I've double-checked since it wasn't mentioned in the issue explicitly).

[pradyunsg]

Did it parse as a LegacySpecifier?

If not, this might be a discrepancy between the logic in the new parser vs Specifier. Thinking a bit more, it might make sense to tweak the parser to try and directly match using the Specifier regex itself.

[pradyunsg]

packaging.requirements.InvalidRequirement: Expected end or semicolon (after version specifier)
     foo >= 1.0-alpha 
         ~~~~~~~~^

The error message gives a hint of what's happening: 1.0-a is getting parsed as the version here. Having this mentioned in OP would've saved me 3 hours. 🤦🏽

[henryiii]

I expect this is what is breaking build’s test suite with 22.0. Probably should verify the dev version fixes build’s tests. I’m on vacation through tomorrow so can’t check till the weekend. Anyone else from @pypa/build?

https://github.com/pypa/build/actions/runs/3649979305

Or it might be #545, actually, and we just need to update our tests.