This is interesting to read. I've used CMake on-and-off for mixed python/C++ code bases, and in particular https://scikit-build.readthedocs.io/en/latest/ https:

This is interesting to read. I've used CMake on-and-off for mixed python/C++ code bases, and in particular https://scikit-build.readthedocs.io/en/latest/ https://scikit-build.readthedocs.io/en/latest/ which aims to integrate with cmake (lightly mentioned here but not evaluated as "getting away from setuptools". But I have never been satisfied with the solutions for out-of-tree builds with python - being able to debug-in-place extensions _and_ eventually install in a single package structure seems to be somewhat in conflict with the way that Python allows you to structure packaging, without lots of environment variable hacks.