pypa/pip

Validate build dependencies when using `--no-build-isolation`

mariocj89 opened this issue · 5 comments

mariocj89 commented

What's the problem this feature will solve?

Prevent builds from running when all required build dependencies are not present.

Describe the solution you'd like

pip fails to build with a descriptive message when a build dependency is missing, providing a nicer user experience (IMHO).

Alternative Solutions

  1. Use python-build which does exactly that.
  2. Manually parse pyproject.toml + generate egg info, get additional build requires and validate those are in the environment.

Additional context
I see the pip docs on --no-build-isolation state "Build dependencies specified by PEP 518 must be already installed if this option is used.". I was wondering whether pip would like to mimic the behaviour that python-build has on --no-isolation(Fail nicely if build dependencies are not present) and if so I'm happy to try and push a patch.

Related: #6718

uranusjr commented

A sanity check to make sure the user actually sets up the environment correctly makes sense to me.

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nchepanov commented

@mariocj89 and I are interested in helping out with this,
@uranusjr @pradyunsg please make sure to tag the issue appropriately?

nchepanov commented

@uranusjr @pradyunsg would you be able to please give a few pointers on where I should start looking in the code and what this change is going to look like?

pradyunsg commented

https://github.com/pypa/pip/blob/main/src/pip/_internal/operations/build/wheel.py and https://github.com/pypa/pip/blob/main/src/pip/_internal/operations/build/metadata.py -- that's where you wanna look for PEP 517 build logic.

If you wanna have a longer chat/discussion about this code, ping me sometime during a work day. :)

  • 👍1
pradyunsg commented

The change needed here is calling build_env.check_requirements(build_deps) at some point in the codebase, since https://github.com/pypa/pip/blob/main/src/pip/_internal/build_env.py#L158 has the relevant logic already IIUC.

I'm pretty sure the things to figure out here are:

  1. Where to make that call.
  2. How to get build_deps to make that call.
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