[jdarwood007]

Fixes #9803

[albertlast]

Connecting to the address from get_ips_for_url() fixes #9803 when that connection succeeds. With cURL disabled, so the socket path is the one used, fetches of https://www.google.com/robots.txt, http://www.google.com/robots.txt and a raw.githubusercontent.com file returned the same as release-2.1. The fsockopen() fallback is the concern:

$fp = @fsockopen(($match[2] ? 'ssl://' : '') . $ip[0] ?? $match[3], ...);

. binds tighter than ??, and $ip is the address as a string, so $ip[0] is its first character. For an address starting with 9 this evaluates to "ssl://9":

$match = [2 => 's', 3 => 'example.com'];
$ip = '93.184.215.14';
var_dump(($match[2] ? 'ssl://' : '') . $ip[0] ?? $match[3]);   // string(7) "ssl://9"

So the fallback never connects. Even written as intended, an ssl:// connection to a bare IP fails certificate verification, so it would need the host name. The host name, though, goes back through the system resolver, which is the mismatch #9803 is about. Trying each address from get_ips_for_url() in turn would avoid needing the fallback at all. Only $ips[0] is tried now.

The stream_context_create() line also ends in trailing tabs.

[albertlast]

I re-ran this against the current head (21aba83). With cURL disabled, so the socket path is the one used, normal fetches work: https://www.google.com/robots.txt, http://www.google.com/robots.txt and a raw.githubusercontent.com file all came back complete.

The fallback still can't help for HTTPS. As PHP evaluates it now:

($match[2] ? 'ssl://' : '') . $ips[0] ?? $match[3]
// 93.184.215.14  ->  "ssl://93.184.215.14"
// 2001:db8::1    ->  "ssl://2001:db8::1"

• An SSL connection to a bare IP fails certificate verification, because there is no host name to check the certificate against. Against a real server, fsockopen('ssl://' . gethostbyname('www.google.com'), 443) failed, while fsockopen('ssl://www.google.com', 443) connected.
• An IPv6 address is not bracketed, so it cannot be told apart from the port.
• It retries $ips[0], the same address stream_socket_client() has just failed to reach.
• ?? $match[3] never applies, because . binds tighter than ??.

Trying each address from get_ips_for_url() in turn with stream_socket_client(), with the same peer_name context, would cover an unreachable first address without the fallback.