[未解决问题记录]python asyncio+aiohttp出现Exception ignored：RuntimeError('Event loop is closed')

找了半天没找到原因，记录一下

操作系统：windows 8.1

python版本：python 3.8.1

aiohttp版本：3.6.2

源码：

 1 import asyncio
 2 import aiohttp
 3 
 4 
 5 async def aiohttp_request_test(url):
 6     async with aiohttp.request('get', url=url) as resp:
 7         await resp.text()
 8         # await asyncio.sleep(1) # A1
 9 
10 
11 async def main():
12     await asyncio.gather(aiohttp_request_test('https://www.baidu.com'))
13 
14 
15 asyncio.run(main())
16 # loop = asyncio.get_event_loop()
17 # loop.run_until_complete(main())

运行以上代码时，出现如下异常：

Exception ignored in: <function _ProactorBasePipeTransport.__del__ at 0x02A8C8E0>
Traceback (most recent call last):
  File "D:\Python\Anaconda3\envs\python38\lib\asyncio\proactor_events.py", line 116, in __del__
    self.close()
  File "D:\Python\Anaconda3\envs\python38\lib\asyncio\proactor_events.py", line 108, in close
    self._loop.call_soon(self._call_connection_lost, None)
  File "D:\Python\Anaconda3\envs\python38\lib\asyncio\base_events.py", line 715, in call_soon
    self._check_closed()
  File "D:\Python\Anaconda3\envs\python38\lib\asyncio\base_events.py", line 508, in _check_closed
    raise RuntimeError('Event loop is closed')
RuntimeError: Event loop is closed

但是在第8行处加上一句await asyncio.sleep(1)后，无异常（方案A）

或者将

asyncio.run(main())

改为：

loop = asyncio.get_event_loop()
loop.run_until_complete(main())

也无异常。（方案B）

（实际使用的时候方案B也会出现上述异常，但这里未能复现，且也可用方案A解决）

我就很奇怪为什么加上一句await asyncio.sleep(1)就不报错了

还有，如果request抛出了一个异常并被捕获的话（将aiohttp_request_test改为如下）：

async def aiohttp_request_test(url):
    try:
        async with aiohttp.request('get', url=url) as resp:
            await resp.text()
    except:
        pass

则也不会报RuntimeError: Event loop is closed

困了，找到原因了再回来补充。