"connect_read_pipe" raises errors on Windows for STDIN

[ivankravets]

BPO	43528
Nosy	@asvetlov, @1st1, @ivankravets
Superseder	bpo-26832: ProactorEventLoop doesn't support stdin/stdout nor files with connect_read_pipe/connect_write_pipe

^{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 = <Date 2022-04-07.08:39:21.056>
created_at = <Date 2021-03-17.12:43:44.117>
labels = ['3.9', 'expert-asyncio']
title = '"connect_read_pipe" raises errors on Windows for STDIN'
updated_at = <Date 2022-04-07.08:39:21.055>
user = 'https://github.com/ivankravets'

bugs.python.org fields:

activity = <Date 2022-04-07.08:39:21.055>
actor = 'kumaraditya'
assignee = 'none'
closed = True
closed_date = <Date 2022-04-07.08:39:21.056>
closer = 'kumaraditya'
components = ['asyncio']
creation = <Date 2021-03-17.12:43:44.117>
creator = 'ivankravets'
dependencies = []
files = []
hgrepos = []
issue_num = 43528
keywords = []
message_count = 1.0
messages = ['388919']
nosy_count = 3.0
nosy_names = ['asvetlov', 'yselivanov', 'ivankravets']
pr_nums = []
priority = 'normal'
resolution = 'duplicate'
stage = 'resolved'
status = 'closed'
superseder = '26832'
type = None
url = 'https://bugs.python.org/issue43528'
versions = ['Python 3.9']

[ivankravets]

Hi there,

It seems that "connect_read_pipe" is not implemented in ProactorEventLoop. Does it make sense to update docs in these places?

• https://docs.python.org/3/library/asyncio-platforms.html#windows
• https://docs.python.org/3/library/asyncio-eventloop.html#working-with-pipes

Or, this is a bug?

# The code to reproduce

import asyncio
import sys


async def read_stdin():
    reader = asyncio.StreamReader()
    protocol = asyncio.StreamReaderProtocol(reader)
    await asyncio.get_running_loop().connect_read_pipe(lambda: protocol, sys.stdin)
    while True:
        line = await reader.readline()
        print("stdin > ", line)


async def main():
    task = asyncio.create_task(read_stdin())
    await asyncio.sleep(5)
    task.cancel()


if __name__ == "__main__":
    asyncio.run(main())

P.S: The "loop.add_reader()" raises "NotImplementedError" which is clear according to the docs.

Thanks in advance!

# Log

C:\Users\USER>.platformio\python3\python.exe test.py
Exception in callback _ProactorReadPipeTransport._loop_reading()
handle: <Handle _ProactorReadPipeTransport._loop_reading()>
Traceback (most recent call last):
  File "C:\Users\USER\.platformio\python3\lib\asyncio\proactor_events.py", line 299, in _loop_reading
    self._read_fut = self._loop._proactor.recv(self._sock, 32768)
  File "C:\Users\USER\.platformio\python3\lib\asyncio\windows_events.py", line 445, in recv
    self._register_with_iocp(conn)
  File "C:\Users\USER\.platformio\python3\lib\asyncio\windows_events.py", line 718, in _register_with_iocp
    _overlapped.CreateIoCompletionPort(obj.fileno(), self._iocp, 0, 0)
OSError: [WinError 6] The handle is invalid

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "C:\Users\USER\.platformio\python3\lib\asyncio\events.py", line 80, in _run
    self._context.run(self._callback, *self._args)
  File "C:\Users\USER\.platformio\python3\lib\asyncio\proactor_events.py", line 309, in _loop_reading
    self._fatal_error(exc, 'Fatal read error on pipe transport')
  File "C:\Users\USER\.platformio\python3\lib\asyncio\proactor_events.py", line 131, in _fatal_error
    self._force_close(exc)
  File "C:\Users\USER\.platformio\python3\lib\asyncio\proactor_events.py", line 134, in _force_close
    if self._empty_waiter is not None and not self._empty_waiter.done():
AttributeError: '_ProactorReadPipeTransport' object has no attribute '_empty_waiter'
Exception ignored in: <function _ProactorBasePipeTransport.__del__ at 0x000002181B927A60>
Traceback (most recent call last):
  File "C:\Users\USER\.platformio\python3\lib\asyncio\proactor_events.py", line 116, in __del__
    self.close()
  File "C:\Users\USER\.platformio\python3\lib\asyncio\proactor_events.py", line 108, in close
    self._loop.call_soon(self._call_connection_lost, None)
  File "C:\Users\USER\.platformio\python3\lib\asyncio\base_events.py", line 746, in call_soon
    self._check_closed()
  File "C:\Users\USER\.platformio\python3\lib\asyncio\base_events.py", line 510, in _check_closed
    raise RuntimeError('Event loop is closed')
RuntimeError: Event loop is closed