Don't recommend --prerelease=allow during build requirement resolution errors

[charliermarsh]

Summary

Closes #3686.

[zanieb]

I don't entirely follow the motivation in the issue. Can you explain a bit?

[charliermarsh]

We don't pass the --prerelease flag to source distribution builds. Recommending --prerelease=allow has no effect.

[zanieb]

Like.. all source distribution builds including those from the registry that are prereleases? Or non-registry ones like local directories or Git repositories?

[charliermarsh]

I don't fully follow the distinction you're referencing but we never pass the --prerelease flag to source distribution builds. Specifically, when we resolve build-system.requires, we don't propagate --prerelease, --resolution, or --no-deps. That applies to all source distribution builds (but only to the build-system.requires, like requires = ["setuptools>=40.8.0"]).

[charliermarsh]

In the linked issue, we failed to resolve requires = ["setuptools>=40.8.0"] when building some package. We then recommended passing --prerelease=allow, but doing so has no effect.

[charliermarsh]

We removed that propagation in #1607 if you want to see a few linked issues. I think it's unclear whether --prerelease should be propagated (--resolution definitely should not, I think that one is much clearer), but it's reasonable for it not to be IMO.

[zanieb]

Ah thanks for clarifying. I somehow missed that we're talking about an error when resolving build requirements. Hence my extreme confusion and dumb questions. This change makes a ton of sense. Can you rephrase the title to make it a bit more obvious? Like...

Don't recommend --prerelease=allow during build requirement resolution errors

[charliermarsh]

Yeah for sure.

[charliermarsh]

Thank you!