Hi @scoder, could you please review this minor change if you have the time?

Note that setup.py now has a build_requires line. And there's also a requirements.txt. I'd rather not triplicate the dependencies across even more files.

But setuptools doesn't recognize the build_requires keyword. It has setup_requires and install_requires, but that would install Cython as normal dependency instead of build dependency package and Cython is not installed when prepare_extensions() is running according to the build log.

But setuptools doesn't recognize the build_requires keyword.

Understood. so that can probably be removed. Still, the GHA and appveyor scripts both use requirements.txt, so that is the single point of truth. Is there a way to make pyproject.toml use requirements.txt?

Is there a way to make pyproject.toml use requirements.txt?

Probably not, project.dependencies can use dynamic metadata to set a file but not for build-system.requires.

I removed the pyproject.toml file and replaced the invalid build_requires keyword with setup_requires. Now Cython can be installed with pip install's --use-pep517 option.

Thanks