UVLoop raises "requires a DNS lookup" on Unix Domain Sockets

[pax0r]

• uvloop version: 0.11.2
• Python version: 3.7
• Platform: Debian 9.5
• Can you reproduce the bug with PYTHONASYNCIODEBUG in env?: yes

When using uvloop with Unix Domain Sockets uvloop.loop.UDPTransport.sendto raises ValueError: UDP.sendto(): address '(socket path)' requires a DNS lookup which is wrong, as there are no DNS lookups for Unix Domain Sockets.

Original Python aioloop works without any problems with this.

I think this can be related to #91

Code to reproduce:

import asyncio
import os
import random
import socket
import string

import uvloop


asyncio.set_event_loop_policy(uvloop.EventLoopPolicy())


def create_sock(path):
    try:
        os.unlink(path)
    except FileNotFoundError:
        pass
    s = socket.socket(socket.AF_UNIX, type=socket.SOCK_DGRAM)
    s.bind(path)
    return s


async def main():
    # Get a reference to the event loop as we plan to use
    # low-level APIs.
    loop = asyncio.get_running_loop()

    message = "Hello World!"
    filename = '/tmp/{}'.format(''.join(random.choice(string.ascii_letters) for i in range(30)))
    sock = create_sock(filename)

    transport, protocol = await loop.create_datagram_endpoint(
        lambda: asyncio.DatagramProtocol(),
        sock=sock)

    transport.sendto(message.encode(), filename)

asyncio.run(main())