IPv6 in URL is missing brackets in proxy CONNECT request

[shnavid-zz]

Long story short

Requests to a URL containing an IPv6 address while using a proxy results in a malformed CONNECT request.

Expected behaviour

The request should make it through the proxy and reach the IPv6 server.

Actual behaviour

The proxy is returning an error (400, Bad request).

Steps to reproduce

async with aiohttp.request(
  'get',
  'https://[2320:10a:c081:56::363]:443/testing.txt',
   proxy="http://whatever:8080",
 ) as response:
     print(response)

tcpdump shows (notice the missing brackets):

CONNECT 2320:10a:c081:56::363:443 HTTP/1.1
Host: [2320:10a:c081:56::363]
Accept: */*
Accept-Encoding: gzip, deflate
User-Agent: Python/3.6 aiohttp/3.5.4

I patched https://github.com/aio-libs/aiohttp/blob/master/aiohttp/client_reqrep.py#L543 to add the brackets and confirmed that the request is going through.

Your environment

aiohttp/3.5.4 (client)
CentOS 7.5

[Dreamsorcerer]

I think there have been some fixes for IPv6, can you retest on the latest release?