Function useTaskListWatcher

source code/hooks/useTaskListWatcher.ts:36–191

({
  taskListId,
  isLoading,
  onSubmitTask,
}: Props)

 * tasks and processes them one at a time.
 */
export function useTaskListWatcher({
  taskListId,
  isLoading,
  onSubmitTask,
}: Props): void {
  const currentTaskRef = useRef<string | null>(null)
  const debounceTimerRef = useRef<ReturnType<typeof setTimeout> | null>(null)

  // Stabilize unstable props via refs so the watcher effect doesn't depend on
  // them. isLoading flips every turn, and onSubmitTask's identity changes
  // whenever onQuery's deps change. Without this, the watcher effect re-runs
  // on every turn, calling watcher.close() + watch() each time — which is a
  // trigger for Bun's PathWatcherManager deadlock (oven-sh/bun#27469).
  const isLoadingRef = useRef(isLoading)
  isLoadingRef.current = isLoading
  const onSubmitTaskRef = useRef(onSubmitTask)
  onSubmitTaskRef.current = onSubmitTask

  const enabled = taskListId !== undefined
  const agentId = taskListId ?? DEFAULT_TASKS_MODE_TASK_LIST_ID

  // checkForTasks reads isLoading and onSubmitTask from refs — always
  // up-to-date, no stale closure, and doesn't force a new function identity
  // per render. Stored in a ref so the watcher effect can call it without
  // depending on it.
  const checkForTasksRef = useRef<() => Promise<void>>(async () => {})
  checkForTasksRef.current = async () => {
    if (!enabled) {
      return
    }

    // Don't need to submit new tasks if we are already working
    if (isLoadingRef.current) {
      return
    }

    const tasks = await listTasks(taskListId)

    // If we have a current task, check if it's been resolved
    if (currentTaskRef.current !== null) {
      const currentTask = tasks.find(t => t.id === currentTaskRef.current)
      if (!currentTask || currentTask.status === 'completed') {
        logForDebugging(
          `[TaskListWatcher] Task #${currentTaskRef.current} is marked complete, ready for next task`,
        )
        currentTaskRef.current = null
      } else {
        // Still working on current task
        return
      }
    }

    // Find an open task with no owner that isn't blocked
    const availableTask = findAvailableTask(tasks)

    if (!availableTask) {
      return
    }