I know Pex uses

pip

as part of locking, but does it use a new enough

pip

with support for PEP 658? https://discuss.python.org/t/pep-658-is-now-live-on-pypi/26693

Yes it does allow you to use latest pip version.

I'm not sure that quite answeres the question regarding the feature though

Well, @refined-addition-53644 did point out the right thing to check. Pex stays up to date with Pip. The last upgrade was on May 1st and support was added for 23.1.1 and 23.1.2, the latter of which was released ~1 week earlier: https://github.com/pantsbuild/pex/releases/tag/v2.1.135

I wonder if the

pip

commands Pex is executing leverages the new feature. I'll have to poke at it when I have time

pip download

is the command for resolves

Ah so the July release of pip should have the change so that pip leverages the new metadata api