[py] CMake: to find Python, use REQUIRED flag ()

Merging branch 'py'  into 'main'.

See merge request !1158

cmake/multipython/FindCustomPython3.cmake

@@ -25,37 +25,14 @@ function(find_custom_python3)
     # the CMake default paths. This is used for finding the _main_
     # Python version.
     if(__DEFAULT_PATH)
-        find_package(Python3 3.${version_minor_min} QUIET
+        find_package(Python3 3.${version_minor_min} REQUIRED
             COMPONENTS Interpreter Development NumPy)
     else()
-        find_package(Python3 3.${version_minor_min} QUIET CONFIG
+        find_package(Python3 3.${version_minor_min} REQUIRED CONFIG
             COMPONENTS Interpreter Development NumPy
             PATHS "${__PATHS}" NO_DEFAULT_PATH)
     endif()
 
-    if(NOT Python3_FOUND)
-        message(FATAL_ERROR
-            "${CMAKE_CURRENT_FUNCTION}: Python 3 not found (minimum version 3.${version_minor_min}).")
-    endif()
-
-    if((${Python3_VERSION_MAJOR} LESS 3) OR (${Python3_VERSION_MINOR} LESS ${version_minor_min}))
-        message(FATAL_ERROR
-            "${CMAKE_CURRENT_FUNCTION}: Python >= 3.${version_minor_min} not found"
-            "(v${Python3_VERSION} is present).")
-    endif()
-
-    if(NOT Python3_Development_FOUND)
-        message(FATAL_ERROR
-            "${CMAKE_CURRENT_FUNCTION}: The development modules for "
-            "Python ${Python3_VERSION} not found. "
-            "Probably, you need to install package `libpython3-dev` (or similar).")
-    endif()
-
-    if(NOT Python3_NumPy_FOUND)
-        message(FATAL_ERROR
-            "${CMAKE_CURRENT_FUNCTION}: Python ${Python3_VERSION}-NumPy not found.")
-    endif()
-
     # store the exported parameters in the internal cache;
     # eg., with pytag 'py39', 'Python3_LIBRARY_DIRS_py39' will be exported, etc.
     set(_exportPars Python3_FOUND Python3_Development_FOUND Python3_NumPy_FOUND