RuntimeError: readuntil() called while another coroutine is already waiting for incoming data

[Tiendil]

Version: redis==4.4.0, Redis: redis:6.2-alpine (docker)

Platform: Python 3.9.16, docker python:3.9

Description: Redis client raises RuntimeError while doing multiple concurrency operations.

Reproduced on 4.4.0, ok on 4.3.5

Example code:

import asyncio
import uuid

from redis.asyncio import Redis


async def main():

    client = Redis(
        host="redis",
        port=6379,
        db=0,
        username=None,
        password=None,
        retry_on_timeout=True,
        single_connection_client=True,
        client_name='test_client',
    )

    # At my PC stable reproduces with n=10, but let set n=100 for better guarantees
    n = 100

    async def problem():
        await client.delete(uuid.uuid4().hex)
        await client.delete(uuid.uuid4().hex)  # <- problem is at this line

    operations = [problem() for i in range(n)]

    await asyncio.gather(*operations)

    print('success!')

Stacktrace:

Traceback (most recent call last):
  File "/app/x.py", line 36, in <module>
    asyncio.get_event_loop().run_until_complete(main())
  File "/usr/local/lib/python3.9/asyncio/base_events.py", line 647, in run_until_complete
    return future.result()
  File "/app/x.py", line 33, in main
    await asyncio.gather(*operations)
  File "/app/x.py", line 29, in problem
    await client.delete(uuid.uuid4().hex)  # <- problem is at this line
  File "/tmp/venv/lib/python3.9/site-packages/redis/asyncio/client.py", line 505, in execute_command
    return await conn.retry.call_with_retry(
  File "/tmp/venv/lib/python3.9/site-packages/redis/asyncio/retry.py", line 59, in call_with_retry
    return await do()
  File "/tmp/venv/lib/python3.9/site-packages/redis/asyncio/client.py", line 481, in _send_command_parse_response
    return await self.parse_response(conn, command_name, **options)
  File "/tmp/venv/lib/python3.9/site-packages/redis/asyncio/client.py", line 524, in parse_response
    response = await connection.read_response()
  File "/tmp/venv/lib/python3.9/site-packages/redis/asyncio/connection.py", line 800, in read_response
    response = await self._parser.read_response(
  File "/tmp/venv/lib/python3.9/site-packages/redis/asyncio/connection.py", line 245, in read_response
    raw = await self._readline()
  File "/tmp/venv/lib/python3.9/site-packages/redis/asyncio/connection.py", line 311, in _readline
    data = await self._stream.readline()
  File "/usr/local/lib/python3.9/asyncio/streams.py", line 540, in readline
    line = await self.readuntil(sep)
  File "/usr/local/lib/python3.9/asyncio/streams.py", line 632, in readuntil
    await self._wait_for_data('readuntil')
  File "/usr/local/lib/python3.9/asyncio/streams.py", line 503, in _wait_for_data
    raise RuntimeError(
RuntimeError: readuntil() called while another coroutine is already waiting for incoming data

[dvora-h]

Fixed in #2568

[iwpnd]

update: created a separate issue