IPv6 support

[snc]

Can you add this feature to bundle?
I made this changes to RedisDsn class in method parseDsn:

    if (preg_match('#^([^:]+)(:(\d+))?$#', $dsn, $matches)) {   //IPv4
        if (!empty($matches[1])) {
            // parse host/ip or socket
            if ('/' === $matches[1]{0}) {
                $this->socket = $matches[1];
            } else {
                $this->host = $matches[1];
            }
        }
        if (null === $this->socket && !empty($matches[3])) {
            // parse port
            $this->port = (int) $matches[3];
        }
    } elseif (preg_match('#^([^.]+)(.(\d+))?$#', $dsn, $matches)) { //IPv6
        if (!empty($matches[1])) {
            // parse host/ip or socket
            if ('/' === $matches[1]{0}) {
                $this->socket = $matches[1];
            } else {
                $this->host = $matches[1];
            }
        }
        if (null === $this->socket && !empty($matches[3])) {
            // parse port
            $this->port = (int) $matches[3];
        }
    }

If this is correct, add it to your repository plz

[snc]

The problem here are the different valid IPv6 formats when used together with a port number.

Some examples of valid IPv6 addresses:
::1
1050:0000:0000:0000:0005:0600:300c:326b
1050:0:0:0:5:600:300c:326b
ff06:0:0:0:0:0:0:c3
ff06::c3

A good regex for this is
'#^(((?=(?>.*?(::))(?!.+\3)))\3?|([\dA-F]{1,4}(\3|:(?!$)|$)|\2))(?4){5}((?4){2}|(25[0-5]|(2[0-4]|1\d|[1-9])?\d)(\.(?7)){3})\z#i'

Resulting DSNs:
redis://ff06::c3
redis://ff06::c3/1

Now when a port is given we have a problem:
redis://ff06::c3:6379

It's impossible to say if :6379 belongs to the IP or not.

[nrk]

IPv6 addresses expressed in URL's syntax should be enclosed in square brackets, for example: redis://[ff06::c3]:6379/1

[snc]

Nice suggestion @nrk 👍
I just converted this issue to a PR. Can you test it @Quidle?

[Seldaek]

Looks good to me, and harmless enough to merge?