An example of a working build-system requires implementation. For those times when your setup.py needs to import a dependency.
This package should not be installed! Instead, prepend setup-requires' setup.py to your own. List only the requirements setup.py itself needs to run in pyproject.toml:
# Example build requirements folling build-deps-pep [build-system] requires = ["cffi", "pycparser >= 2.10"]
(Only the name and required versions are allowed, not the full pip syntax of URLs to specific repositories. Instead, install internal setup-requires dependencies manually or set PIP_FIND_LINKS=... to point to the necessary repositories.)
When run, setup-requires' setup.py checks that each distribution listed is installed; if not, it installs them into the ./setup-requires directory in a pip subprocess. The normal setup.py contents can simply be pasted below the bootstrap code.