Network is unreachable with IPv6 enabled sites and no local IPv6 route

[lilydjwg]

🐞 Describe the bug

When requesting HTTPS, IPv6 enabled sites but without local IPv6 route, I get Network is unreachable errors.

💡 To Reproduce

1. python3 -m venv venv and . venv/bin/activate
2. pip install -U aiohttp
3. Run code:

import asyncio
import aiohttp

async def main():
  async with aiohttp.ClientSession() as session:
    r = await session.get('https://www.cloudflare.com/cdn-cgi/trace')
    print(await r.text())

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

4. See error.

💡 Expected behavior

📋 Logs/tracebacks

Traceback (most recent call last):                                                                                                      
  File "/home/lilydjwg/tmpfs/venv/lib/python3.8/site-packages/aiohttp/connector.py", line 946, in _wrap_create_connection
    return await self._loop.create_connection(*args, **kwargs)  # type: ignore  # noqa                                   
  File "/usr/lib/python3.8/asyncio/base_events.py", line 1025, in create_connection
    raise exceptions[0]                                                                                                                 
  File "/usr/lib/python3.8/asyncio/base_events.py", line 1010, in create_connection
    sock = await self._connect_sock(        
  File "/usr/lib/python3.8/asyncio/base_events.py", line 924, in _connect_sock
    await self.sock_connect(sock, address)
  File "/usr/lib/python3.8/asyncio/selector_events.py", line 496, in sock_connect                                                      
    return await fut
  File "/usr/lib/python3.8/asyncio/selector_events.py", line 501, in _sock_connect
    sock.connect(address)
OSError: [Errno 101] Network is unreachable

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "t.py", line 12, in <module>
    asyncio.run(main())
  File "/usr/lib/python3.8/asyncio/runners.py", line 44, in run
    return loop.run_until_complete(main)
  File "/usr/lib/python3.8/asyncio/base_events.py", line 616, in run_until_complete
    return future.result()
  File "t.py", line 8, in main
    r = await session.get('https://www.cloudflare.com/cdn-cgi/trace')
  File "/home/lilydjwg/tmpfs/venv/lib/python3.8/site-packages/aiohttp/client.py", line 490, in _request
    conn = await self._connector.connect(
  File "/home/lilydjwg/tmpfs/venv/lib/python3.8/site-packages/aiohttp/connector.py", line 528, in connect
    proto = await self._create_connection(req, traces, timeout)
  File "/home/lilydjwg/tmpfs/venv/lib/python3.8/site-packages/aiohttp/connector.py", line 868, in _create_connection
    _, proto = await self._create_direct_connection(
  File "/home/lilydjwg/tmpfs/venv/lib/python3.8/site-packages/aiohttp/connector.py", line 1023, in _create_direct_connection
    raise last_exc
  File "/home/lilydjwg/tmpfs/venv/lib/python3.8/site-packages/aiohttp/connector.py", line 999, in _create_direct_connection
    transp, proto = await self._wrap_create_connection(
  File "/home/lilydjwg/tmpfs/venv/lib/python3.8/site-packages/aiohttp/connector.py", line 953, in _wrap_create_connection
    raise client_error(req.connection_key, exc) from exc
aiohttp.client_exceptions.ClientConnectorError: Cannot connect to host www.cloudflare.com:443 ssl:default [Network is unreachable]

📋 Your version of the Python

$ python --version
Python 3.8.6

📋 Your version of the aiohttp/yarl/multidict distributions

$ python -m pip show aiohttp
Name: aiohttp
Version: 3.7.0
Summary: Async http client/server framework (asyncio)
Home-page: https://github.com/aio-libs/aiohttp
Author: Nikolay Kim
Author-email: [email protected]
License: Apache 2
Location: /home/lilydjwg/tmpfs/venv/lib/python3.8/site-packages
Requires: yarl, attrs, async-timeout, chardet, multidict
Required-by: 

$ python -m pip show multidict
Name: multidict
Version: 5.0.0
Summary: multidict implementation
Home-page: https://github.com/aio-libs/multidict
Author: Andrew Svetlov
Author-email: [email protected]
License: Apache 2
Location: /home/lilydjwg/tmpfs/venv/lib/python3.8/site-packages
Requires: 
Required-by: yarl, aiohttp

$ python -m pip show yarl
Name: yarl
Version: 1.6.2
Summary: Yet another URL library
Home-page: https://github.com/aio-libs/yarl/
Author: Andrew Svetlov
Author-email: [email protected]
License: Apache 2
Location: /home/lilydjwg/tmpfs/venv/lib/python3.8/site-packages
Requires: idna, multidict
Required-by: aiohttp

📋 Additional context

This errors caused my tests to fail on Travis-CI.

There is no issue with HTTP. There is #5110 when IPv6 is accessible.

I switched to www.cloudflare.com because pypi.org reidrects http to https.

[asvetlov]

#5118 fixes it I guess

[bitnom]

Confirmed broken but only for https/SSL: https://repl.it/@synthetisoft/aiohttpactproxy

[lilydjwg]

Yes, it's fixed. Thanks!