bugfix: pg_escape_string() in serendipity_db_escape_string() works again

[HQJaTu]

Docs: https://www.php.net/manual/en/function.pg-escape-string.php

In PHP 8.1+ there is no default connection. A mandatory connection must be given as a parameter. This PR restores PostgreSQL support for S9y.

Not sure if PHP <8.1 must be supported. If yes, PHP_MAJOR_VERSION and PHP_MINOR_VERSION could be checked to determine which interface of pg_escape_string() needs to be used.

[onli]

Great :)

Not sure if PHP <8.1 must be supported. If yes, PHP_MAJOR_VERSION and PHP_MINOR_VERSION could be checked to determine which interface of pg_escape_string() needs to be used.

It would be nice to support older PHP versions. It makes upgrades for old blogs a lot easier, and so far we were still compatible I think.

[HQJaTu]

Checked after the commit. Correction: PHP 8.1 is still supported by security updates.
https://www.php.net/supported-versions.php

My own agenda is to move into PHP 8.2. When stable status reached, then bump into 8.3 to see what breaks.

[onli]

What do you think about this instead (untested)?

if (version_compare(PHP_VERSION, '8.1.0', '<')) {
    # Versions before 8.1 give the connection by default
    return pg_escape_string($string);
}

That's how the core would usually express that if, and I think it's a bit clearer, isn't it?