pip-build-hook: enable validation of build dependencies

[Kiskae]

Per https://pip.pypa.io/en/stable/cli/pip_wheel/#cmdoption-check-build-dependencies

It turns out that unlike pypa, pip only checks build dependencies if it is told to.

This makes the missing build dependencies a lot clearer, since it immediately lists all missing dependencies rather than fail when it can't find them.

Example output for uri-template:

Processing /build/uri-template-1.3.0
ERROR: Some build dependencies for file:///build/uri-template-1.3.0 are missing: 'setuptools_scm'.

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This change turns out to have surfaced a few hidden bugs with existing test cases, additional commits fix these issues.

Contribution checklist (recommended but not always applicable/required):

• There's an automated test for this change
• Commit messages or code include references to related issues or PRs (including third parties)
• Commit messages are conventional - examples from the log include "feat: add changelog files to fixup hook", "fix(contourpy): allow wheel usage", and "test: add sqlalchemy2 test"

[l0b0]

Thank you! Would you be OK to include a copy of a relevant error message in the ticket, for reference?

[Kiskae]

Thank you! Would you be OK to include a copy of a relevant error message in the ticket, for reference?

Added an example to the issue body, getting it to trigger intentionally was trickier than I expected

[cpcloud]

One difficulty here is that this check enforces version constraints, which I think might make adding the build time dependency check a non-starter without some substituteInPlace calls in the right place.

[cpcloud]

Another issue is that this flag results in a failure for packages that are missing build time dependencies that are circular. In some cases we have to remove those build time dependencies to prevent infinite recursion.

So, for example, if we add the flag we'd need to add jupyterlab as a build time dependency to jupyterlab-widgets which would pass the build time check but then fail with an infinite recursion error later.

[cpcloud]

I do think there's value in checking for missing build-time dependencies but I'm not sure how to surface only those and ignore the errors coming from constraint violations.

[cpcloud]

Happy to accept the changes other than the build hook modification, merge those shortly!

[cpcloud]

Passing locally on:

• x86_64-darwin
• aarch64-darwin
• x86_64-linux