CMake can't find header-only library installed with Chocolatey

[robertodr]

Description

I'm trying to build wheels on Windows for a project that uses the Eigen3 header-only library. I'm running choco install eigen with CIBW_BEFORE_ALL_WINDOWS, as suggested in the documentation. From the logs, I can see that Chocolatey should already have set up all the paths correctly for CMake to find this dependency. However, the build fails because CMake can't find the package. I've tried to set the Eigen3_ROOT environment variable and/or passing -DEigen3_DIR option through SKBUILD_CMAKE_ARGS but none seem to do the trick. What am I missing?

Build log

https://pipelinesghubeus23.actions.githubusercontent.com/CeqyNvChuFKPSplumdvzHI0kSDdWeR7czI7LxDTAdEb8UF7BQd/_apis/pipelines/1/runs/98/signedlogcontent/5?urlExpires=2023-09-13T08%3A41%3A28.5705260Z&urlSigningMethod=HMACV1&urlSignature=ZF%2Fu8uaMCZ79U%2FgaRlU7RL6ceGolUppAv0xS7Xv2z34%3D

CI config

https://github.com/maxscheurer/cppe/actions/runs/6170004263/workflow

[henryiii]

Does the chocolatey install of Eigen include the CMake config file?

[henryiii]

FYI, I usually use submodules or FetchContent for Eigen, and include it in the SDist. It's just some header files, and that way you control the exact version.

[robertodr]

Does the chocolatey install of Eigen include the CMake config file?

From the logs (which I now see I didn't link correctly in the issue 😞) it appears so:

eigen v3.4.0 [Approved]
  eigen package files install completed. Performing other installation steps.
  HKEY_LOCAL_MACHINE\SOFTWARE\Kitware\CMake\Packages\Eigen3
  @{CMakePackageDir=C:\ProgramData\chocolatey\lib\eigen\share\cmake; PSPath=Microsoft.PowerShell.Core\Registry::HKEY_LOCAL_MACHINE\SOFTWARE\Kitware\CMake\Packages\Eigen3; PSParentPath=Microsoft.PowerShell.Core\Registry::HKEY_LOCAL_MACHINE\SOFTWARE\Kitware\CMake\Packages; PSChildName=Eigen3; PSDrive=HKLM; PSProvider=Microsoft.PowerShell.Core\Registry}
   The install of eigen was successful.
    Software install location not explicitly set, it could be in package or
    default install location of installer.

FYI, I usually use submodules or FetchContent for Eigen, and include it in the SDist. It's just some header files, and that way you control the exact version.

This however sounds like the better solution! Do you have an example of using FetchContent and including Eigen in the SDist that I could follow?