[FR] Ability to dynamically specify "build wheel" dependencies

[mgorny]

What's the problem this feature will solve?

Some projects have specific dynamic dependencies for build* commands such as cmake. Currently, such dependencies either have to be specified a. as build-system.requires, or b. via setup_requires. The former method only permits static dependencies, so we can't express "[cmake] only if no system CMake is available", the latter is deprecated — and both of them apply to source distributions, whereas we need it only for wheel builds.

Describe the solution you'd like

I'd like a non-deprecated option to pass wheel building requirements to setup() function, so they'd be returned by the backend's get_requires_for_build_wheel() method.

Alternative Solutions

The alternative is for every such package to use a custom backend based on setuptools', and have the backend override get_requires_for_build_wheel(). However, it seems a bit of an overkill.

Additional context

No response

Code of Conduct

• I agree to follow the PSF Code of Conduct

[webknjaz]

However, it seems a bit of an overkill.

FWIW having a thin wrapper is documented and what I'd go for. But having hatchling-like hooks would be nice too, I suppose.