_ProactorBasePipeTransport.abort() after _ProactorBasePipeTransport.close() does not cancel writes

[graingert]

BPO	44428
Nosy	@gvanrossum, @asvetlov, @ambv, @1st1, @graingert

^{Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.}

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GitHub fields:

assignee = None
closed_at = None
created_at = <Date 2021-06-15.21:00:19.644>
labels = ['3.8', '3.9', '3.10', 'expert-asyncio']
title = '_ProactorBasePipeTransport.abort() after _ProactorBasePipeTransport.close() does not cancel writes'
updated_at = <Date 2021-07-12.16:40:18.078>
user = 'https://github.com/graingert'

bugs.python.org fields:

activity = <Date 2021-07-12.16:40:18.078>
actor = 'graingert'
assignee = 'none'
closed = False
closed_date = None
closer = None
components = ['asyncio']
creation = <Date 2021-06-15.21:00:19.644>
creator = 'graingert'
dependencies = []
files = []
hgrepos = []
issue_num = 44428
keywords = []
message_count = 2.0
messages = ['395896', '396558']
nosy_count = 5.0
nosy_names = ['gvanrossum', 'asvetlov', 'lukasz.langa', 'yselivanov', 'graingert']
pr_nums = []
priority = 'normal'
resolution = None
stage = None
status = 'open'
superseder = None
type = None
url = 'https://bugs.python.org/issue44428'
versions = ['Python 3.8', 'Python 3.9', 'Python 3.10']

[graingert]

demo program:

import asyncio
import socket
import threading

async def amain():
 family = socket.AddressFamily.AF_INET
 sock = socket.socket(family, socket.SOCK_STREAM)
 sock.settimeout(1)
 sock.bind(('localhost', 0))
 sock.listen()
 host, port = sock.getsockname()[:2]

 event = threading.Event()

 def serve():
 client, _ = sock.accept()
 with client:
 client.recv(1)
 event.wait()

 t = threading.Thread(target=serve, daemon=True)
 t.start()

 reader, writer = await asyncio.open_connection(host=host, port=port)
 try:
 while True:
 writer.write(b"\x00" * 4096 * 682 * 2)
 await asyncio.wait_for(writer.drain(), 2)
 print("wrote")
 except asyncio.TimeoutError:
 print("timed out")

 writer.close()
 await asyncio.sleep(0)
 writer.transport.abort()
 print("waiting close")
 await writer.wait_closed() # never finishes on ProactorEventLoop
 print("closed")
 event.set()
 t.join()

asyncio.run(amain())

it looks like it was fixed for the selector eventloop in 2546a17

but not for the proactor https://github.com/python/cpython/blame/8fe57aacc7bf9d9af84803b69dbb1d66597934c6/Lib/asyncio/proactor_events.py#L140

[graingert]

nosying the author of the selector_events fix

[kumaraditya303]

@gvanrossum Do you recall the details as you fixed the selector event loop race ?

[gvanrossum]

Sorry, you're on your own here. I have no recollection of this fix.