`_SSLProtocolTransport.close()` cannot close the connection until timeout or EOF

• uvloop version: 0.16.0
• Python version: CPython 3.9.12
• Platform: Debian GNU/Linux bookworm/sid x86_64
• Can you reproduce the bug with PYTHONASYNCIODEBUG in env?: yes
• Does uvloop behave differently from vanilla asyncio? How?: yes, the bug is only reproducible with uvloop

Desciption

If uvloop is enabled, as long as EOF is not reached, even if the response, connection, and session are all closed, the server from which aiohttp requested resources, will still keep sending packets to the aiohttp-client for some time. However, the bug is only reproducible with uvloop enabled.

To reproduce

aiohttp[speedups]==3.8.1
uvloop==0.16.0

import asyncio
import aiohttp
import uvloop
import logging

logging.basicConfig(level=logging.DEBUG)


async def fetch(url):
    async with aiohttp.ClientSession() as session:
        async with session.get(url) as response:
            logging.debug(response)
            logging.debug(response.content)


async def reproduce(wait):
    await fetch('https://sgp-ping.vultr.com/vultr.com.1000MB.bin')
    await asyncio.sleep(wait)  # now you will see that the file is still being downloaded


def main(enable_uvloop):
    if enable_uvloop:
        logging.info('********** Using uvloop **********')
        uvloop.install()  # the bug is only reproducible with uvloop
    else:
        logging.info('********** Using asyncio **********')
    loop = asyncio.new_event_loop()
    loop.set_debug(True)  # or set env PYTHONASYNCIODEBUG=1, not necessary to reproduce the bug
    asyncio.set_event_loop(loop)
    loop.run_until_complete(reproduce(15 if enable_uvloop else 5))
    loop.close()


if __name__ == '__main__':
    main(enable_uvloop=False)
    main(enable_uvloop=True)
    input('Press Enter to exit')

Log and screenshot

INFO:root:********** Using asyncio **********
DEBUG:asyncio:Using selector: EpollSelector
DEBUG:asyncio:Get address info sgp-ping.vultr.com:443, type=<SocketKind.SOCK_STREAM: 1>, flags=<AddressInfo.AI_ADDRCONFIG: 32>
INFO:asyncio:Getting address info sgp-ping.vultr.com:443, type=<SocketKind.SOCK_STREAM: 1>, flags=<AddressInfo.AI_ADDRCONFIG: 32> took 209.423ms: [(<AddressFamily.AF_INET: 2>, <SocketKind.SOCK_STREAM: 1>, 6, '', ('45.32.100.168', 443))]
DEBUG:asyncio:<asyncio.sslproto.SSLProtocol object at 0x7fc80064dfa0> starts SSL handshake
DEBUG:asyncio:<asyncio.sslproto.SSLProtocol object at 0x7fc80064dfa0>: SSL handshake took 225.2 ms
DEBUG:asyncio:<asyncio.TransportSocket fd=6, family=AddressFamily.AF_INET, type=SocketKind.SOCK_STREAM, proto=6, laddr=('192.168.1.101', 51708), raddr=('45.32.100.168', 443)> connected to 45.32.100.168:443: (<asyncio.sslproto._SSLProtocolTransport object at 0x7fc7ff9b5a00>, <aiohttp.client_proto.ResponseHandler object at 0x7fc800205b20>)
DEBUG:root:<ClientResponse(https://sgp-ping.vultr.com/vultr.com.1000MB.bin) [200 OK]>
<CIMultiDictProxy('Server': 'nginx', 'Date': 'Sat, 21 May 2022 00:29:55 GMT', 'Content-Type': 'application/octet-stream', 'Content-Length': '1048576000', 'Last-Modified': 'Mon, 20 Sep 2021 19:54:01 GMT', 'Connection': 'keep-alive', 'Etag': '"6148e6d9-3e800000"', 'Expires': 'Sun, 22 May 2022 00:29:55 GMT', 'Cache-Control': 'max-age=86400', 'X-Frame-Options': 'DENY', 'X-Content-Type-Options': 'nosniff', 'Access-Control-Allow-Origin': '*', 'Accept-Ranges': 'bytes')>

DEBUG:root:<StreamReader 15968 bytes>
DEBUG:asyncio:<asyncio.sslproto.SSLProtocol object at 0x7fc80064dfa0>: SSL error in data received
Traceback (most recent call last):
  File "/usr/lib/python3.9/asyncio/sslproto.py", line 534, in data_received
    ssldata, appdata = self._sslpipe.feed_ssldata(data)
  File "/usr/lib/python3.9/asyncio/sslproto.py", line 206, in feed_ssldata
    self._sslobj.unwrap()
  File "/usr/lib/python3.9/ssl.py", line 948, in unwrap
    return self._sslobj.shutdown()
ssl.SSLError: [SSL: APPLICATION_DATA_AFTER_CLOSE_NOTIFY] application data after close notify (_ssl.c:2756)
DEBUG:asyncio:Close <_UnixSelectorEventLoop running=False closed=False debug=True>
INFO:root:********** Using uvloop **********
DEBUG:asyncio:<uvloop.loop.SSLProtocol object at 0x7fc8040f8b40> starts SSL handshake
DEBUG:asyncio:<uvloop.loop.SSLProtocol object at 0x7fc8040f8b40>: SSL handshake took 227.0 ms
DEBUG:root:<ClientResponse(https://sgp-ping.vultr.com/vultr.com.1000MB.bin) [200 OK]>
<CIMultiDictProxy('Server': 'nginx', 'Date': 'Sat, 21 May 2022 00:30:01 GMT', 'Content-Type': 'application/octet-stream', 'Content-Length': '1048576000', 'Last-Modified': 'Mon, 20 Sep 2021 19:54:01 GMT', 'Connection': 'keep-alive', 'Etag': '"6148e6d9-3e800000"', 'Expires': 'Sun, 22 May 2022 00:30:01 GMT', 'Cache-Control': 'max-age=86400', 'X-Frame-Options': 'DENY', 'X-Content-Type-Options': 'nosniff', 'Access-Control-Allow-Origin': '*', 'Accept-Ranges': 'bytes')>

DEBUG:root:<StreamReader 15968 bytes>
Press Enter to exit	

The bug has also been reported to aiohttp: https://github.com/aio-libs/aiohttp/issues/6762

提供されている aiohttp と uvloop の reproducer から始め、その動作を vanilla asyncio およびログに記録された uvloop.loop.SSLProtocol パスと比較します。関連する aiohttp issue をコンテキストとして使用し、session と response を閉じることで、timeout や EOF を待たずに以降のダウンロードが停止することを確認します。