Save and restore error messages when rolling back after failed init

Fixes https://github.com/libsdl-org/SDL/issues/12439

(cherry picked from commit 1a7c20698625b1b64f2a67c226622295616b8ee5)

src/SDL.c

@@ -356,7 +356,9 @@ bool SDL_InitSubSystem(SDL_InitFlags flags)
             SDL_IncrementSubsystemRefCount(SDL_INIT_VIDEO);
             if (!SDL_VideoInit(NULL)) {
                 SDL_DecrementSubsystemRefCount(SDL_INIT_VIDEO);
+                SDL_PushError();
                 SDL_QuitSubSystem(SDL_INIT_EVENTS);
+                SDL_PopError();
                 goto quit_and_error;
             }
         } else {
@@ -381,7 +383,9 @@ bool SDL_InitSubSystem(SDL_InitFlags flags)
             SDL_IncrementSubsystemRefCount(SDL_INIT_AUDIO);
             if (!SDL_InitAudio(NULL)) {
                 SDL_DecrementSubsystemRefCount(SDL_INIT_AUDIO);
+                SDL_PushError();
                 SDL_QuitSubSystem(SDL_INIT_EVENTS);
+                SDL_PopError();
                 goto quit_and_error;
             }
         } else {
@@ -406,7 +410,9 @@ bool SDL_InitSubSystem(SDL_InitFlags flags)
             SDL_IncrementSubsystemRefCount(SDL_INIT_JOYSTICK);
             if (!SDL_InitJoysticks()) {
                 SDL_DecrementSubsystemRefCount(SDL_INIT_JOYSTICK);
+                SDL_PushError();
                 SDL_QuitSubSystem(SDL_INIT_EVENTS);
+                SDL_PopError();
                 goto quit_and_error;
             }
         } else {
@@ -430,7 +436,9 @@ bool SDL_InitSubSystem(SDL_InitFlags flags)
             SDL_IncrementSubsystemRefCount(SDL_INIT_GAMEPAD);
             if (!SDL_InitGamepads()) {
                 SDL_DecrementSubsystemRefCount(SDL_INIT_GAMEPAD);
+                SDL_PushError();
                 SDL_QuitSubSystem(SDL_INIT_JOYSTICK);
+                SDL_PopError();
                 goto quit_and_error;
             }
         } else {
@@ -493,7 +501,9 @@ bool SDL_InitSubSystem(SDL_InitFlags flags)
             SDL_IncrementSubsystemRefCount(SDL_INIT_CAMERA);
             if (!SDL_CameraInit(NULL)) {
                 SDL_DecrementSubsystemRefCount(SDL_INIT_CAMERA);
+                SDL_PushError();
                 SDL_QuitSubSystem(SDL_INIT_EVENTS);
+                SDL_PopError();
                 goto quit_and_error;
             }
         } else {
@@ -511,7 +521,11 @@ bool SDL_InitSubSystem(SDL_InitFlags flags)
     return SDL_ClearError();
 
 quit_and_error:
-    SDL_QuitSubSystem(flags_initialized);
+    {
+        SDL_PushError();
+        SDL_QuitSubSystem(flags_initialized);
+        SDL_PopError();
+    }
     return false;
 }
 

src/SDL_error_c.h

@@ -46,4 +46,16 @@ typedef struct SDL_error
 // Defined in SDL_thread.c
 extern SDL_error *SDL_GetErrBuf(bool create);
 
+// Macros to save and restore error values
+#define SDL_PushError() \
+    char *saved_error = SDL_strdup(SDL_GetError())
+
+#define SDL_PopError()                          \
+    do {                                        \
+        if (saved_error) {                      \
+            SDL_SetError("%s", saved_error);    \
+            SDL_free(saved_error);              \
+        }                                       \
+    } while (0)
+
 #endif // SDL_error_c_h_