[FindPython,FindPython2,FindPython3] No REQUIRED_VARS specified for FIND_PACKAGE_HANDLE_STANDARD_ARGS()
If neither REQUIRED nor QUIET has been passed to find_package(Python
then it will error out with
CMake Error at C:/Program Files/CMake/share/cmake-3.16/Modules/FindPackageHandleStandardArgs.cmake:226 (message):
No REQUIRED_VARS specified for FIND_PACKAGE_HANDLE_STANDARD_ARGS()
Call Stack (most recent call first):
C:/Program Files/CMake/share/cmake-3.16/Modules/FindPython.cmake:347 (find_package_handle_standard_args)
taken from https://github.com/root-project/root/commit/89c089127f9ac57ca45348f7ac8c71624b68955d
Reason: https://gitlab.kitware.com/cmake/cmake/-/blob/73f81c5070e7880efe5acfc1827f60524116cee1/Modules/FindPython.cmake#L396 passes _Python_REQUIRED_VARS
but that is never set and hence empty.
Side note: IMO the check at https://gitlab.kitware.com/cmake/cmake/-/blob/73f81c5070e7880efe5acfc1827f60524116cee1/Modules/FindPython.cmake#L393 is even wrong. FPHSA should be doing that already.
Edited by Alexander Grund