PHP 8.1 Deprecation Warning for mysqli_real_connect

[nickchomey]

I'm getting these deprecation warnings in the debug.log

[16-Oct-2022 23:14:52 UTC] PHP Deprecated:  mysqli_real_connect(): Passing null to parameter #5 ($database) of type ?string is deprecated in /home/seeingtheforest.net/public_html/wp-includes/wp-db.php on line 1753
[16-Oct-2022 23:14:52 UTC] PHP Deprecated:  mysqli_real_connect(): Passing null to parameter #6 ($port) of type ?int is deprecated in /home/seeingtheforest.net/public_html/wp-includes/wp-db.php on line 1753
[16-Oct-2022 23:14:52 UTC] PHP Deprecated:  mysqli_real_connect(): Passing null to parameter #7 ($socket) of type ?string is deprecated in /home/seeingtheforest.net/public_html/wp-includes/wp-db.php on line 1753

I'm using PHP 8.1, so assume it is due to that. It probably happens in 8.0 as well.

If I trace the error with Xdebug, I can see that the problem is
a) null is simply hardcoded for param 5
b) port and socket are set to null if they aren't included in wp-config.php e.g. define('DB_HOST', "localhost");

If I manually change param 5 to "" and

$port    = "";
$socket  = "";

in wp-includes/wp-db.php -> parse_db_host()

then the problem goes away.

[nickchomey]

Duplicate of #54877.

Closing this as it is already an issue here https://core.trac.wordpress.org/ticket/54877#comment:42

Though, just one clarification - it should be $port = 0 since it is an int.

[nickchomey]

I've decided to close this as well as remove my comment from #54877 as it seems like there's a bug in Litespeed's lsphp81 that isn't treating mysqli_real_connect's parameters as nullable.

[SergeyBiryukov]

Hi there, welcome back to WordPress Trac!

Just adding some context from #54877:

• The $database, $port, and $socket parameters of mysqli_real_connect() should actually be nullable, as they are null by default in ​PHP source, per comment:15:ticket:54877.
• The issue might have to do with using ​LiteSpeed PHP, per comment:42:ticket:54877.

P.S. Ah, it looks like this is already noted above.

[SergeyBiryukov]

#60073 was marked as a duplicate.