fix(lua): only disable vim.schedule() when closing main loop (#26090)

src/nvim/event/loop.c

@@ -17,6 +17,7 @@ void loop_init(Loop *loop, void *data)
 {
   uv_loop_init(&loop->uv);
   loop->recursive = 0;
+  loop->closing = false;
   loop->uv.data = loop;
   loop->children = kl_init(WatcherPtr);
   loop->events = multiqueue_new_parent(loop_on_put, loop);
@@ -149,6 +150,7 @@ static void loop_walk_cb(uv_handle_t *handle, void *arg)
 bool loop_close(Loop *loop, bool wait)
 {
   bool rv = true;
+  loop->closing = true;
   uv_mutex_destroy(&loop->mutex);
   uv_close((uv_handle_t *)&loop->children_watcher, NULL);
   uv_close((uv_handle_t *)&loop->children_kill_timer, NULL);

src/nvim/event/loop.h

@@ -40,6 +40,7 @@ typedef struct loop {
   uv_async_t async;
   uv_mutex_t mutex;
   int recursive;
+  bool closing;  ///< Set to true if loop_close() has been called
 } Loop;
 
 #define CREATE_EVENT(multiqueue, handler, argc, ...) \

src/nvim/lua/executor.c

@@ -366,17 +366,17 @@ static void nlua_schedule_event(void **argv)
 static int nlua_schedule(lua_State *const lstate)
   FUNC_ATTR_NONNULL_ALL
 {
-  // If Nvim is exiting don't schedule tasks to run in the future. Any refs
-  // allocated here will not be cleaned up otherwise
-  if (exiting) {
-    return 0;
-  }
-
   if (lua_type(lstate, 1) != LUA_TFUNCTION) {
     lua_pushliteral(lstate, "vim.schedule: expected function");
     return lua_error(lstate);
   }
 
+  // If main_loop is closing don't schedule tasks to run in the future,
+  // otherwise any refs allocated here will not be cleaned up.
+  if (main_loop.closing) {
+    return 0;
+  }
+
   LuaRef cb = nlua_ref_global(lstate, 1);
 
   multiqueue_put(main_loop.events, nlua_schedule_event,