asyncio.open_connection(local_addr=('localhost', port)) fails with TypeError: AF_INET address must be a pair (host, port)

[ecatmur]

BPO	42342
Nosy	@asvetlov, @1st1, @ecatmur

^{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 2020-11-13.10:23:37.431>
labels = ['type-bug', '3.8', 'expert-asyncio']
title = "asyncio.open_connection(local_addr=('localhost', port)) fails with TypeError: AF_INET address must be a pair (host, port)"
updated_at = <Date 2020-11-13.10:23:37.431>
user = 'https://github.com/ecatmur'

bugs.python.org fields:

activity = <Date 2020-11-13.10:23:37.431>
actor = 'ecatmur2'
assignee = 'none'
closed = False
closed_date = None
closer = None
components = ['asyncio']
creation = <Date 2020-11-13.10:23:37.431>
creator = 'ecatmur2'
dependencies = []
files = []
hgrepos = []
issue_num = 42342
keywords = []
message_count = 1.0
messages = ['380874']
nosy_count = 3.0
nosy_names = ['asvetlov', 'yselivanov', 'ecatmur2']
pr_nums = []
priority = 'normal'
resolution = None
stage = None
status = 'open'
superseder = None
type = 'behavior'
url = 'https://bugs.python.org/issue42342'
versions = ['Python 3.8']

Linked PRs

• GH-86508: skip binding to local addresses of different family in asyncio.open_connection #100615
• [3.11] GH-86508: skip binding to local addresses of different family in asyncio.open_connection (GH-100615) #100741
• [3.10] GH-86508: skip binding to local addresses of different family in asyncio.open_connection (GH-100615) #100742

[ecatmur]

Context: CentOS 7.8.2003, Python 3.8 from SCL. localhost has IPv4 and IPv6 bindings, IPv6 first:
$ python -c "import socket;print(socket.getaddrinfo('localhost',0,type=socket.SOCK_STREAM))"
[(<AddressFamily.AF_INET6: 10>, <SocketKind.SOCK_STREAM: 1>, 6, '', ('::1', 0, 0, 0)), (<AddressFamily.AF_INET: 2>, <SocketKind.SOCK_STREAM: 1>, 6, '', ('127.0.0.1', 0))]

import asyncio
async def main():
    await asyncio.open_connection('localhost', 9990, local_addr=('localhost', 9991))
asyncio.run(main())

Traceback (most recent call last):
  File "async.py", line 4, in <module>
    asyncio.run(main())
  File "/opt/rh/rh-python38/root/usr/lib64/python3.8/asyncio/runners.py", line 43, in run
    return loop.run_until_complete(main)
  File "/opt/rh/rh-python38/root/usr/lib64/python3.8/asyncio/base_events.py", line 608, in run_until_complete
    return future.result()
  File "async.py", line 3, in main
    await asyncio.open_connection('10.10.10.10', 9990, local_addr=('localhost', 9991))
  File "/opt/rh/rh-python38/root/usr/lib64/python3.8/asyncio/streams.py", line 52, in open_connection
    transport, _ = await loop.create_connection(
  File "/opt/rh/rh-python38/root/usr/lib64/python3.8/asyncio/base_events.py", line 1002, in create_connection
    sock = await self._connect_sock(
  File "/opt/rh/rh-python38/root/usr/lib64/python3.8/asyncio/base_events.py", line 904, in _connect_sock
    sock.bind(laddr)
TypeError: AF_INET address must be a pair (host, port)

It looks like this has a similar root cause to bpo-35302 - we should be filtering local addrinfos by family for valid combinations.