Python 3.10 is required when building ICON

This is the error message I get:


  Could NOT find Python: Found unsuitable version "3.9.21", but required is
  at least "3.10" (found /usr/bin/python3.9, found components: Interpreter)
Call Stack (most recent call first):
  /software/stack/cepp/2025.10/Linux/x86_64/rhel-9.5/utilities/cmake/4.1.2/prefix/share/cmake-4.1/Modules/FindPackageHandleStandardArgs.cmake:589 (_FPHSA_FAILURE_MESSAGE)
  /software/stack/cepp/2025.10/Linux/x86_64/rhel-9.5/utilities/cmake/4.1.2/prefix/share/cmake-4.1/Modules/FindPython/Support.cmake:4169 (find_package_handle_standard_args)
  /software/stack/cepp/2025.10/Linux/x86_64/rhel-9.5/utilities/cmake/4.1.2/prefix/share/cmake-4.1/Modules/FindPython.cmake:685 (include)
  projects/icon.cmake:49 (find_package)
  CMakeLists.txt:238 (include)

https://gitlab.dkrz.de/hpcw/hpcw/-/blob/eb52826628d21a082b60e381cc0a5f57619ca716/projects/icon.cmake#L49

Sourcing a python 3.11 made this error disappear on the system I was playing with.

Either we add python as a internal dependency in HPCW (I vote for no); or we add a new requirement in the documentation; or find a way to workaround this in Icon (disable python?)

Edited by Antoine Morvan