Add hint to make SDL handle dbus_shutdown()

include/SDL3/SDL_hints.h

@@ -2706,7 +2706,6 @@ extern "C" {
  */
 #define SDL_HINT_AUDIO_DEVICE_SAMPLE_FRAMES "SDL_AUDIO_DEVICE_SAMPLE_FRAMES"
 
-
 /**
  * Request SDL_AppIterate() be called at a specific rate.
  *
@@ -2721,6 +2720,22 @@ extern "C" {
  */
 #define SDL_HINT_MAIN_CALLBACK_RATE "SDL_MAIN_CALLBACK_RATE"
 
+/**
+ * Let SDL handle dbus_shutdown().
+ *
+ * Only enable this option if no other dependency uses D-Bus.
+ *
+ * This option tells SDL that it can safely call dbus_shutdown() when
+ * SDL_Quit() is called. You must ensure that no other library still uses
+ * D-Bus when SDL_Quit() is called, otherwise resources will be freed while
+ * they are still in use, which results in undefined behavior and likely a
+ * crash.
+ *
+ * Use this option to prevent memory leaks if your application doesn't use
+ * D-Bus other than through SDL.
+ */
+#define SDL_HINT_SHUTDOWN_DBUS_ON_QUIT "SDL_SHUTDOWN_DBUS_ON_QUIT"
+
 
 /**
  *  An enumeration of hint priorities

src/SDL.c

@@ -517,13 +517,13 @@ void SDL_Quit(void)
     SDL_QuitTicks();
 #endif
 
-    SDL_ClearHints();
-    SDL_AssertionsQuit();
-
 #ifdef SDL_USE_LIBDBUS
     SDL_DBus_Quit();
 #endif
 
+    SDL_ClearHints();
+    SDL_AssertionsQuit();
+
     SDL_QuitProperties();
     SDL_QuitLog();
 

src/core/linux/SDL_dbus.c

@@ -183,14 +183,12 @@ void SDL_DBus_Quit(void)
         dbus.connection_close(dbus.session_conn);
         dbus.connection_unref(dbus.session_conn);
     }
-/* Don't do this - bug 3950
-   dbus_shutdown() is a debug feature which closes all global resources in the dbus library. Calling this should be done by the app, not a library, because if there are multiple users of dbus in the process then SDL could shut it down even though another part is using it.
-*/
-#if 0
-    if (dbus.shutdown) {
+
+    SDL_bool q = SDL_GetHintBoolean(SDL_HINT_SHUTDOWN_DBUS_ON_QUIT, SDL_FALSE);
+    if (q == SDL_TRUE && dbus.shutdown) {
         dbus.shutdown();
     }
-#endif
+
     SDL_zero(dbus);
     UnloadDBUSLibrary();
     SDL_free(inhibit_handle);