small Python-related CMake cleanup (#5916)

Author: firewave

CMakeLists.txt

@@ -56,8 +56,8 @@ if(LIBXML2_XMLLINT_EXECUTABLE)
 
     add_custom_target(createXMLExamples DEPENDS errorlist-xml example-xml)
 
-    if(PYTHON_EXECUTABLE)
-        add_custom_target(checkCWEEntries ${PYTHON_EXECUTABLE} ${CMAKE_SOURCE_DIR}/tools/listErrorsWithoutCWE.py -F ${CMAKE_BINARY_DIR}/errorlist.xml
+    if(Python_EXECUTABLE)
+        add_custom_target(checkCWEEntries ${Python_EXECUTABLE} ${CMAKE_SOURCE_DIR}/tools/listErrorsWithoutCWE.py -F ${CMAKE_BINARY_DIR}/errorlist.xml
                 DEPENDS errorlist-xml)
     endif()
 

cmake/clang_tidy.cmake

@@ -1,3 +1,5 @@
+# TODO: bail out when Python_EXECUTABLE is not set
+
 if (NOT CMAKE_DISABLE_PRECOMPILE_HEADERS)
     # clang-tidy and clang need to have the same version when precompiled headers are being used
     if (CMAKE_CXX_COMPILER_ID MATCHES "Clang")
@@ -24,7 +26,7 @@ if (RUN_CLANG_TIDY_NAMES)
         message(STATUS "NPROC=${NPROC}")
 
         # disable all compiler warnings since we are just interested in the tidy ones
-        add_custom_target(run-clang-tidy ${PYTHON_EXECUTABLE} ${RUN_CLANG_TIDY} -p=${CMAKE_BINARY_DIR} -j ${NPROC} -quiet)
+        add_custom_target(run-clang-tidy ${Python_EXECUTABLE} ${RUN_CLANG_TIDY} -p=${CMAKE_BINARY_DIR} -j ${NPROC} -quiet)
         if (BUILD_GUI)
             add_dependencies(run-clang-tidy gui-build-deps)
             if (BUILD_TESTS)

cmake/findDependencies.cmake

@@ -43,21 +43,24 @@ set(CMAKE_INCLUDE_CURRENT_DIR ON)
 if (CMAKE_VERSION VERSION_EQUAL "3.12" OR CMAKE_VERSION VERSION_GREATER "3.12")
     find_package(Python COMPONENTS Interpreter)
     if (NOT Python_Interpreter_FOUND)
-        message(WARNING "No python interpreter found. Therefore, the match compiler is switched off.")
+        message(WARNING "No python interpreter found - disabling matchcompiler.")
         set(USE_MATCHCOMPILER_OPT "Off")
-    else()
-        set(PYTHON_EXECUTABLE ${Python_EXECUTABLE})
     endif()
 else()
     find_package(PythonInterp 3 QUIET)
     if (NOT PYTHONINTERP_FOUND)
         set(PYTHONINTERP_FOUND "")
         find_package(PythonInterp 2.7 QUIET)
         if (NOT PYTHONINTERP_FOUND AND NOT USE_MATCHCOMPILER_OPT STREQUAL "Off")
-            message(WARNING "No python interpreter found. Therefore, the match compiler is switched off.")
+            message(WARNING "No python interpreter found - disabling matchcompiler.")
             set(USE_MATCHCOMPILER_OPT "Off")
         endif()
     endif()
+    if (PYTHONINTERP_FOUND)
+        set(Python_EXECUTABLE ${PYTHON_EXECUTABLE})
+        set(Python_VERSION ${PYTHON_VERSION_STRING})
+        set(Python_Interpreter_FOUND ${PYTHONINTERP_FOUND})
+    endif()
 endif()
 
 if (NOT USE_BUNDLED_TINYXML2)

cmake/printInfo.cmake

@@ -2,6 +2,7 @@ message( STATUS "------------------ General configuration for ${PROJECT_NAME} ${
 message( STATUS )
 message( STATUS "CMake Version =         ${CMAKE_VERSION}")
 message( STATUS "CMake Generator =       ${CMAKE_GENERATOR}")
+message( STATUS )
 message( STATUS "Compiler =              ${CMAKE_CXX_COMPILER_ID}")
 message( STATUS "Compiler Version =      ${CMAKE_CXX_COMPILER_VERSION}")
 message( STATUS "Build type =            ${CMAKE_BUILD_TYPE}")
@@ -19,6 +20,11 @@ message( STATUS "COMPILE_DEFINITIONS (global) =  ${DirCompileDefs}" )
 get_directory_property( DirCompileOptions DIRECTORY ${CMAKE_SOURCE_DIR} COMPILE_OPTIONS )
 message( STATUS "COMPILE_OPTIONS (global) =  ${DirCompileOptions}" )
 message( STATUS )
+if (Python_Interpreter_FOUND)
+    message( STATUS "Python_VERSION =        ${Python_VERSION}" )
+    message( STATUS "Python_EXECUTABLE =     ${Python_EXECUTABLE}" )
+endif()
+message( STATUS )
 message( STATUS "---------------------------------------------------------" )
 message( STATUS "ANALYZE_MEMORY =        ${ANALYZE_MEMORY}" )
 message( STATUS "ANALYZE_ADDRESS =       ${ANALYZE_ADDRESS}" )
@@ -67,11 +73,6 @@ endif()
 message( STATUS )
 message( STATUS "USE_THREADS =           ${USE_THREADS}" )
 message( STATUS "CMAKE_THREAD_LIBS_INIT = ${CMAKE_THREAD_LIBS_INIT}" )
-if (NOT USE_MATCHCOMPILER_OPT STREQUAL "Off")
-    message( STATUS )
-    message( STATUS "PYTHON_VERSION_STRING = ${PYTHON_VERSION_STRING}" )
-    message( STATUS "PYTHON_EXECUTABLE =     ${PYTHON_EXECUTABLE}" )
-endif()
 message( STATUS )
 message( STATUS "USE_BUNDLED_TINYXML2 =  ${USE_BUNDLED_TINYXML2}" )
 if (NOT USE_BUNDLED_TINYXML2)

lib/CMakeLists.txt

@@ -15,7 +15,7 @@ function(build_src output filename)
     endif()
     add_custom_command(
         OUTPUT ${outfile}
-        COMMAND ${PYTHON_EXECUTABLE} "${PROJECT_SOURCE_DIR}/tools/matchcompiler.py" 
+        COMMAND ${Python_EXECUTABLE} "${PROJECT_SOURCE_DIR}/tools/matchcompiler.py"
                 --read-dir="${CMAKE_CURRENT_SOURCE_DIR}" 
                 --prefix="mc_" 
                 --line