[a.fixPythonWrappers] Minor fix to CMake scripts which produce the Python wrappers

Merging branch 'a.fixPythonWrappers'  into 'main'.

Related to issue #223

See merge request !2295

cmake/multipython/MakePythonWheel.cmake

@@ -145,7 +145,8 @@ function(add_library_to_wheel lib)
     if(lib_LIBRARY_PY)
         add_custom_command(TARGET ${lib}
             POST_BUILD
-            COMMAND ${CMAKE_COMMAND} -E copy "$<TARGET_PROPERTY:${lib},_LIBRARY_PY>" ${_dst}
+            COMMAND ${CMAKE_COMMAND} -E copy "${lib_LIBRARY_PY}" ${_dst}
+            DEPENDS lib${lib}_py_wrappers
             COMMENT "Add Python wrapper-script of library ${lib} to the Python wheel..."
         )
     endif()

cmake/multipython/SwigLib.cmake

@@ -55,24 +55,32 @@ function(SwigLib name lib swigtmpdir)
             ";-I${LibHeinz_INCLUDE_DIR}"
             ";-I${CMAKE_SOURCE_DIR};-I${CMAKE_BINARY_DIR}/inc")
 
-        add_custom_command(
-            OUTPUT ${AUTO_WRAP_DIR}/lib${lib}.py
-            COMMAND ${Python3_EXECUTABLE} ${SWIG_DIR}/tweaks.py
-                   ${swigtmpdir}/lib${lib}.py
-                   ${AUTO_WRAP_DIR}/lib${lib}.py
-            DEPENDS ${swigtmpdir}/lib${lib}.py
-            )
-        add_custom_command(
-            OUTPUT ${swigtmpdir}/lib${lib}.py
+        add_custom_target(lib${lib}_py_wrappers ALL
+            BYPRODUCTS ${swigtmpdir}/lib${lib}.py
                    ${AUTO_WRAP_DIR}/lib${lib}_wrap.h
                    ${AUTO_WRAP_DIR}/lib${lib}_wrap.cpp
+                   ${AUTO_WRAP_DIR}/lib${lib}.py
+            # produce the Python wrapper
             COMMAND ${SWIG_EXECUTABLE} ${SWIG_FLAGS} ${SWIG_DIR}/lib${lib}.i
+            # amend the Python wrapper
+            COMMAND ${Python3_EXECUTABLE} ${SWIG_DIR}/tweaks.py
+                    ${swigtmpdir}/lib${lib}.py
+                    ${AUTO_WRAP_DIR}/lib${lib}.py
             DEPENDS ${swig_dependencies} ${include_files}
+            COMMENT "SWIG: build Python wrapper ${AUTO_WRAP_DIR}/lib${lib}.py"
             )
 
         string(REPLACE ";" " " SWIG_FLAGS_STR "${SWIG_FLAGS}")
         set(SWIG_FLAGS_STR "${SWIG_FLAGS_STR}" CACHE INTERNAL "")
         set(SWIG_DIR "${SWIG_DIR}" CACHE INTERNAL "")
+    else()
+        # assumes that lib${lib}_wrap.h, lib${lib}_wrap.cpp and lib${lib}.py
+        # are already present in ${AUTO_WRAP_DIR}
+        add_custom_target(lib${lib}_py_wrappers ALL
+            DEPENDS ${AUTO_WRAP_DIR}/lib${lib}_wrap.h
+            ${AUTO_WRAP_DIR}/lib${lib}_wrap.cpp
+            ${AUTO_WRAP_DIR}/lib${lib}.py
+        )
     endif()
 
     # include Python and Numpy headers and link to Python shared library