cmake: use compatible interface properties to disallow linking to a different version of SDL

CMakeLists.txt

@@ -3278,6 +3278,8 @@ if(NOT WINDOWS_STORE AND NOT SDL2_DISABLE_SDL2MAIN)
   if (NOT ANDROID)
     set_target_properties(SDL2main PROPERTIES DEBUG_POSTFIX "${SDL_CMAKE_DEBUG_POSTFIX}")
   endif()
+  set_property(TARGET SDL2main APPEND PROPERTY COMPATIBLE_INTERFACE_STRING "SDL_VERSION")
+  set_property(TARGET SDL2main PROPERTY INTERFACE_SDL_VERSION "SDL2")
 endif()
 
 if(ANDROID)
@@ -3365,8 +3367,10 @@ if(SDL_SHARED)
     set_target_properties(SDL2 PROPERTIES DEBUG_POSTFIX "${SDL_CMAKE_DEBUG_POSTFIX}")
   endif()
   # Use `Compatible Interface Properties` to allow consumers to enforce a shared/static library
-  set_property(TARGET SDL2 PROPERTY INTERFACE_SDL2_SHARED TRUE)
   set_property(TARGET SDL2 APPEND PROPERTY COMPATIBLE_INTERFACE_BOOL SDL2_SHARED)
+  set_property(TARGET SDL2 PROPERTY INTERFACE_SDL2_SHARED TRUE)
+  set_property(TARGET SDL2 APPEND PROPERTY COMPATIBLE_INTERFACE_STRING "SDL_VERSION")
+  set_property(TARGET SDL2 PROPERTY INTERFACE_SDL_VERSION "SDL2")
 endif()
 
 if(SDL_STATIC)
@@ -3393,8 +3397,10 @@ if(SDL_STATIC)
     set_target_properties(SDL2-static PROPERTIES DEBUG_POSTFIX "${SDL_CMAKE_DEBUG_POSTFIX}")
   endif()
   # Use `Compatible Interface Properties` to allow consumers to enforce a shared/static library
-  set_property(TARGET SDL2-static PROPERTY INTERFACE_SDL2_SHARED FALSE)
   set_property(TARGET SDL2-static APPEND PROPERTY COMPATIBLE_INTERFACE_BOOL SDL2_SHARED)
+  set_property(TARGET SDL2-static PROPERTY INTERFACE_SDL2_SHARED FALSE)
+  set_property(TARGET SDL2-static APPEND PROPERTY  COMPATIBLE_INTERFACE_STRING "SDL_VERSION")
+  set_property(TARGET SDL2-static PROPERTY INTERFACE_SDL_VERSION "SDL2")
 endif()
 
 set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -DSDL_BUILD_MAJOR_VERSION=${SDL_MAJOR_VERSION}")
@@ -3416,6 +3422,8 @@ if(SDL_TEST)
       "$<INSTALL_INTERFACE:${CMAKE_INSTALL_INCLUDEDIR}>"
       "$<INSTALL_INTERFACE:${CMAKE_INSTALL_INCLUDEDIR}/SDL2>")
   target_link_libraries(SDL2_test PRIVATE ${EXTRA_TEST_LIBS})
+  set_property(TARGET SDL2_test APPEND PROPERTY COMPATIBLE_INTERFACE_STRING "SDL_VERSION")
+  set_property(TARGET SDL2_test PROPERTY INTERFACE_SDL_VERSION "SDL2")
 endif()
 
 ##### Installation targets #####

VisualC/pkg-support/cmake/sdl2-config.cmake

@@ -68,6 +68,8 @@ if(EXISTS "${_sdl2_library}" AND EXISTS "${_sdl2_dll_library}")
                 IMPORTED_LOCATION "${_sdl2_dll_library}"
                 COMPATIBLE_INTERFACE_BOOL "SDL2_SHARED"
                 INTERFACE_SDL2_SHARED "ON"
+                COMPATIBLE_INTERFACE_STRING "SDL_VERSION"
+                INTERFACE_SDL_VERSION "SDL2"
         )
     endif()
     set(SDL2_SDL2_FOUND TRUE)
@@ -84,6 +86,8 @@ if(EXISTS "${_sdl2main_library}")
         set_target_properties(SDL2::SDL2main
         PROPERTIES
             IMPORTED_LOCATION "${_sdl2main_library}"
+            COMPATIBLE_INTERFACE_STRING "SDL_VERSION"
+            INTERFACE_SDL_VERSION "SDL2"
         )
     endif()
     set(SDL2_SDL2main_FOUND TRUE)
@@ -100,6 +104,8 @@ if(EXISTS "${_sdl2test_library}")
             PROPERTIES
                 INTERFACE_INCLUDE_DIRECTORIES "${SDL2_INCLUDE_DIRS}"
                 IMPORTED_LOCATION "${_sdl2test_library}"
+                COMPATIBLE_INTERFACE_STRING "SDL_VERSION"
+                INTERFACE_SDL_VERSION "SDL2"
         )
     endif()
     set(SDL2_SDL2test_FOUND TRUE)

Xcode/SDL/pkg-support/resources/CMake/sdl2-config.cmake

@@ -57,6 +57,8 @@ if(NOT TARGET SDL2::SDL2)
             INTERFACE_LINK_OPTIONS "SHELL:-F \"${SDL2_FRAMEWORK_PARENT_PATH}\";SHELL:-framework SDL2"
             COMPATIBLE_INTERFACE_BOOL "SDL2_SHARED"
             INTERFACE_SDL2_SHARED "ON"
+            COMPATIBLE_INTERFACE_STRING "SDL_VERSION"
+            INTERFACE_SDL_VERSION "SDL2"
     )
 endif()
 set(SDL2_SDL2_FOUND TRUE)

sdl2-config.cmake.in

@@ -73,6 +73,8 @@ if(EXISTS "${_sdl2main_library}")
     set_target_properties(SDL2::SDL2main
       PROPERTIES
         IMPORTED_LOCATION "${_sdl2main_library}"
+        COMPATIBLE_INTERFACE_STRING "SDL_VERSION"
+        INTERFACE_SDL_VERSION "SDL2"
     )
     if(WIN32)
       # INTERFACE_LINK_OPTIONS needs CMake 3.13
@@ -116,6 +118,8 @@ if(WIN32)
         IMPORTED_LINK_INTERFACE_LANGUAGES "C"
         IMPORTED_IMPLIB "${_sdl2_implib}"
         IMPORTED_LOCATION "${_sdl2_dll}"
+        COMPATIBLE_INTERFACE_STRING "SDL_VERSION"
+        INTERFACE_SDL_VERSION "SDL2"
       )
     endif()
     set(SDL2_SDL2_FOUND TRUE)
@@ -135,6 +139,8 @@ else()
         INTERFACE_LINK_DIRECTORIES "${_sdl2_libdirs}"
         IMPORTED_LINK_INTERFACE_LANGUAGES "C"
         IMPORTED_LOCATION "${_sdl2_shared}"
+        COMPATIBLE_INTERFACE_STRING "SDL_VERSION"
+        INTERFACE_SDL_VERSION "SDL2"
       )
     endif()
     set(SDL2_SDL2_FOUND TRUE)
@@ -155,6 +161,8 @@ if(EXISTS "${_sdl2_static}")
         INTERFACE_LINK_LIBRARIES "${_sdl2_link_libraries};${_sdl2_static_private_libs}"
         INTERFACE_LINK_DIRECTORIES "${_sdl2_libdirs};${_sdl2_static_private_libdirs}"
         IMPORTED_LINK_INTERFACE_LANGUAGES "C"
+        COMPATIBLE_INTERFACE_STRING "SDL_VERSION"
+        INTERFACE_SDL_VERSION "SDL2"
     )
   endif()
   set(SDL2_SDL2-static_FOUND TRUE)
@@ -174,6 +182,8 @@ if(EXISTS "${_sdl2test_library}")
         IMPORTED_LOCATION "${_sdl2test_library}"
         INTERFACE_INCLUDE_DIRECTORIES "${SDL2_INCLUDE_DIR}"
         IMPORTED_LINK_INTERFACE_LANGUAGES "C"
+        COMPATIBLE_INTERFACE_STRING "SDL_VERSION"
+        INTERFACE_SDL_VERSION "SDL2"
     )
   endif()
   set(SDL2_SDL2test_FOUND TRUE)