scikit-build-core with cibuildwheel unable to find compiler in Windows GitHub Action runner?

[golmschenk]

Hello! I'm attempting to build a wheel using cibuildwheel and scikit-build-core (note, scikit-build-core, not scikit-build). The project includes Fortran code and I'm using GitHub Actions as the CI runner. The issue I'm running into is that I can't seem to find a way to get the Windows build's CMake to recognize the Fortran compiler. I'm not entirely sure if the issue stems from cibuildwheel, scikit-build-core, or the interaction between the two. As such, I have posted this on their discussions as well (pypa/cibuildwheel#1515). I apologize for duplicated posting, and will close this post if the issue ends up being primarily on the cibuildwheel end of things. I've attempted various ways of installing additional compilers on the runner and passing the existing compiler paths to cibuildwheel. Any attempt I've made (beyond those that result in earlier errors) have resulted in the error:
No CMAKE_Fortran_COMPILER could be found.. The wheel compiles without issue on both manylinux and macOS.

I've setup a minimal repository demonstrating the issue: https://github.com/golmschenk/minimal_fortran_scikit_build_core_cibuildwheel_example

The GitHub Action showing the failing build can be seen here: https://github.com/golmschenk/minimal_fortran_scikit_build_core_cibuildwheel_example/actions/runs/5205201435

Any suggestions on how to get the cibuildwheel and scikit-build-core combination working? Thank you for your time!

[golmschenk]

It seems my primary issue was that I did not have a good grasp on how variable expansion works in the standard Windows shells. I was able to get successful builds by using the awvwgk/setup-fortran GitHub action to install MinGW, then setting the environment variable in cibuildwheel step CMAKE_GENERATOR: MinGW Makefiles.