build-system.requires list is not installed in the venv when calling vulcan lock about vulcan-py HOT 2 CLOSED

I know quadprog==0.1.10 has this dependency fixed, but jsut in case other packages might not be so nice

from vulcan-py.

Unfortunately I don't think it is possible to correctly handle this case (and indeed, setuptools.build_meta will also fail to install the following:

$ command cat pyproject.toml 
[build-system]
requires = [ "setuptools<58", "Cython==0.27.3", "wheel"]
build-backend = "setuptools.build_meta"
$ command cat setup.cfg 
[options]
install_requires = 
    quadprog==0.1.6

With the same error:

      File "/tmp/pip-install-551h99mw/quadprog_62dd3219c5324e93ac88e2f65d3f04ba/setup.py", line 17, in <module>
        from Cython.Build import cythonize
    ModuleNotFoundError: No module named 'Cython'

)

We can't install the requires dependencies into the lock virtualenvs because that would impact and potentially conflict with the actual dependnecies of the project.

With respect to installing first cython and then quadprog, I would indeed expect that to work when done one after the other. But in the same way as above, the following fails: python -m pip install Cython==0.27.3 quadprog==0.1.6

from vulcan-py.