UseSWIG: Add new behavior for better support files management

fixes: #17840

Tests/UseSWIG/ModuleVersion2/CMakeLists.txt

@@ -0,0 +1,56 @@
+cmake_minimum_required(VERSION 3.1)
+
+project(TestModuleVersion2 CXX)
+
+include(CTest)
+
+find_package(SWIG REQUIRED)
+include(${SWIG_USE_FILE})
+
+find_package(Python2 REQUIRED COMPONENTS Interpreter Development)
+find_package(Python3 REQUIRED COMPONENTS Interpreter Development)
+
+set (UseSWIG_MODULE_VERSION 2)
+unset(CMAKE_SWIG_FLAGS)
+
+set_property(SOURCE "../example.i" PROPERTY CPLUSPLUS ON)
+set_property(SOURCE "../example.i" PROPERTY COMPILE_OPTIONS -includeall)
+
+set_property(SOURCE "../example.i"
+  PROPERTY GENERATED_INCLUDE_DIRECTORIES "${CMAKE_CURRENT_SOURCE_DIR}/..")
+
+swig_add_library(example1
+                 LANGUAGE python
+                 SOURCES ../example.i ../example.cxx)
+set_target_properties (example1 PROPERTIES
+  OUTPUT_NAME example
+  LIBRARY_OUTPUT_DIRECTORY "${CMAKE_CURRENT_BINARY_DIR}/Python2"
+  ARCHIVE_OUTPUT_DIRECTORY "${CMAKE_CURRENT_BINARY_DIR}/Python2"
+  RUNTIME_OUTPUT_DIRECTORY "${CMAKE_CURRENT_BINARY_DIR}/Python2")
+target_link_libraries(example1 PRIVATE Python2::Python)
+
+# re-use sample interface file for another plugin
+swig_add_library(example2
+                 LANGUAGE python
+                 SOURCES ../example.i ../example.cxx)
+set_target_properties (example2 PROPERTIES
+  OUTPUT_NAME example
+  LIBRARY_OUTPUT_DIRECTORY "${CMAKE_CURRENT_BINARY_DIR}/Python3"
+  ARCHIVE_OUTPUT_DIRECTORY "${CMAKE_CURRENT_BINARY_DIR}/Python3"
+  RUNTIME_OUTPUT_DIRECTORY "${CMAKE_CURRENT_BINARY_DIR}/Python3")
+target_link_libraries(example2 PRIVATE Python3::Python)
+
+
+if (WIN32)
+  set (PS $<SEMICOLON>)
+else()
+  set (PS ":")
+endif()
+
+add_test (NAME ModuleVersion2.example1
+  COMMAND "${CMAKE_COMMAND}" -E env "PYTHONPATH=$<TARGET_PROPERTY:example1,SWIG_SUPPORT_FILES_DIRECTORY>${PS}$<TARGET_FILE_DIR:example1>"
+  "${Python2_EXECUTABLE}" "${CMAKE_CURRENT_SOURCE_DIR}/../runme.py")
+
+add_test (NAME ModuleVersion2.example2
+  COMMAND "${CMAKE_COMMAND}" -E env "PYTHONPATH=$<TARGET_PROPERTY:example2,SWIG_SUPPORT_FILES_DIRECTORY>${PS}$<TARGET_FILE_DIR:example2>"
+  "${Python3_EXECUTABLE}" "${CMAKE_CURRENT_SOURCE_DIR}/../runme.py")