SDL: Remove the reference to the thread when it is detached

SDL Commits
1 
From e3d9f1172c7eeb4fadddc636853b4e86c3609476 Mon Sep 17 00:00:00 2001
From: Sam Lantinga <[EMAIL REDACTED]>
Date: Sun, 16 Feb 2025 07:55:58 -0800
Subject: [PATCH] Remove the reference to the thread when it is detached

Fixes https://github.com/libsdl-org/SDL/issues/12301
---
 src/thread/SDL_thread.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/src/thread/SDL_thread.c b/src/thread/SDL_thread.c
index ee9f9bbb56f79..99cb9dd7f15ba 100644
--- a/src/thread/SDL_thread.c
+++ b/src/thread/SDL_thread.c
@@ -334,7 +334,6 @@ void SDL_RunThread(SDL_Thread *thread)
     if (!SDL_CompareAndSwapAtomicInt(&thread->state, SDL_THREAD_ALIVE, SDL_THREAD_COMPLETE)) {
         // Clean up if something already detached us.
         if (SDL_GetThreadState(thread) == SDL_THREAD_DETACHED) {
-            SDL_SetObjectValid(thread, SDL_OBJECT_TYPE_THREAD, false);
             SDL_free(thread->name); // Can't free later, we've already cleaned up TLS
             SDL_free(thread);
         }
@@ -457,7 +456,7 @@ bool SDL_SetCurrentThreadPriority(SDL_ThreadPriority priority)
 
 void SDL_WaitThread(SDL_Thread *thread, int *status)
 {
-    if (!ThreadValid(thread) || SDL_GetThreadState(thread) == SDL_THREAD_DETACHED) {
+    if (!ThreadValid(thread)) {
         if (status) {
             *status = -1;
         }
@@ -488,6 +487,9 @@ void SDL_DetachThread(SDL_Thread *thread)
         return;
     }
 
+    // The thread may vanish at any time, it's no longer valid
+    SDL_SetObjectValid(thread, SDL_OBJECT_TYPE_THREAD, false);
+
     // Grab dibs if the state is alive+joinable.
     if (SDL_CompareAndSwapAtomicInt(&thread->state, SDL_THREAD_ALIVE, SDL_THREAD_DETACHED)) {
         SDL_SYS_DetachThread(thread);