# RuntimeError: 另一个循环正在运行时无法运行事件循环

- **ID:** `python/asyncio-loop-already-running-nested`
- **领域:** python
- **类别:** runtime_error
- **验证级别:** ai_generated
- **修复率:** 80%

## 根因

在已运行于同一循环的协程内部调用了 loop.run_until_complete()，导致 asyncio 禁止的嵌套循环执行。

## 版本兼容性

| 版本 | 状态 | 引入 | 弃用 |
|------|------|------|------|
| 3.8 | active | — | — |
| 3.9 | active | — | — |
| 3.10 | active | — | — |
| 3.11 | active | — | — |
| 3.12 | active | — | — |

## 解决方案

1. **** (95% 成功率)
   ```
   async def outer():
    # WRONG: loop.run_until_complete(inner())
    await inner()  # correct
   ```
2. **** (88% 成功率)
   ```
   result = await asyncio.to_thread(sync_blocking_fn, arg1, arg2)
   ```

## 无效尝试

- **** — get_event_loop returns the running loop; run_until_complete still raises. (90% 失败率)
- **** — The loop is still running; a yield point does not allow re-entrant run_until_complete. (85% 失败率)