Consider reading pyproject.toml metadata directly

[charliermarsh]

According to the spec:

A build back-end MUST honour statically-specified metadata (which means the metadata did not list the key in dynamic).

In other words, if a field is defined in the [project] section, and not declared as dynamic, the spec suggests it must be used... verbatim? I think? So in theory we could read the metadata directly without executing any PEP 517 hooks.

This would not work for Hatch projects that rely on context formatting: pypa/hatch#1331

[charliermarsh]

Yes, I believe this should work per Paul Moore's comment here: pypa/pip#11440 (comment)

[charliermarsh]

This could be a nice optimization for resolution.

[hauntsaninja]

I've had a similar PR lying around for pip-compile for a while: jazzband/pip-tools#1964

[bluss]

Sorry if this is too tangential, but in my reading environment variables are not part of dependency specs (only requirements files) - thus ${PROJECT_ROOT} usage could also be a problem here, which is another case?

Example https://pdm-project.org/latest/usage/dependency/#local-dependencies

[charliermarsh]

My impression is that those usages are not spec compliant. But they do exist in the wild, so we'll have to detect them and skip the optimization in that case.