[nrfconnect] Fix CMake error when two Python versions are installed (#…

…24384)

When pigweed virtual environment is used, and the pigweed's
Python is older than python installed in the system, build
might fail because find_package(Python3) would select the
system Python while find_package(Python3 ...) invoked by
Zephyr would use different constraints that select the
pigweed Python. It turns out CMake does not like calling
find_package() with different constraints in the same scope.

Signed-off-by: Damian Krolik <damian.krolik@nordicsemi.no>

Signed-off-by: Damian Krolik <damian.krolik@nordicsemi.no>

config/nrfconnect/app/check-nrfconnect-version.cmake

@@ -14,15 +14,23 @@
 # limitations under the License.
 #
 
-find_package(Python3 REQUIRED)
+# This function is only needed to prevent find_package from polluting the global
+# variable namespace before loading Zephyr CMake module. Without this workaround
+# the build may fail because Zephyr calls find_package(Python3) with different
+# constraints and CMake is not able to handle such a scenario.
+function(check_nrfconnect_version)
+ find_package(Python3 REQUIRED)
 
-# Check nRF Connect SDK version in the CMake configuration phase
-execute_process(
- WORKING_DIRECTORY ${CMAKE_CURRENT_LIST_DIR}/../../..
- COMMAND ${Python3_EXECUTABLE} scripts/setup/nrfconnect/update_ncs.py --check --quiet)
+ # Check nRF Connect SDK version in the CMake configuration phase
+ execute_process(
+  WORKING_DIRECTORY ${CMAKE_CURRENT_LIST_DIR}/../../..
+  COMMAND ${Python3_EXECUTABLE} scripts/setup/nrfconnect/update_ncs.py --check --quiet)
 
-# Check nRF Connect SDK version in the build phase
-add_custom_target(check-nrfconnect-version ALL
- WORKING_DIRECTORY ${CMAKE_CURRENT_LIST_DIR}/../../..
- COMMAND ${Python3_EXECUTABLE} scripts/setup/nrfconnect/update_ncs.py --check --quiet || (exit 0)
- USES_TERMINAL)
+ # Check nRF Connect SDK version in the build phase
+ add_custom_target(check-nrfconnect-version ALL
+ WORKING_DIRECTORY ${CMAKE_CURRENT_LIST_DIR}/../../..
+ COMMAND ${Python3_EXECUTABLE} scripts/setup/nrfconnect/update_ncs.py --check --quiet || (exit 0)
+ USES_TERMINAL)
+endfunction()
+
+check_nrfconnect_version()