Deprecation / better optimization for backdrop_match_path()?

[laryn]

Description of the bug

I'm seeing this warning on a site that I'm working on locally:

Deprecated function: preg_quote(): Passing null to parameter #1 ($str) of type string is deprecated in backdrop_match_path() (line 311 of /var/www/vhosts/sotp/live/core/includes/path.inc).

Steps To Reproduce

I'm still looking for ways to reproduce with a minimal installation.

Actual behavior

Deprecated warning is generated due to a deprecation.

Expected behavior

Deprecation is not triggered and no warning is generated.

Additional information

This may be due to the Domain module as I haven't seen it elsewhere and the site I'm looking at locally is a D7 upgrade that is using Domain. That said, in looking at backdrop_match_path() it seems we may be able to just skip processing if no patterns exist (ie. if $patterns is empty) and avoid this whole deprecation, which occurs further down when $patterns is submitted to preg_quote.

Backdrop 1.30.0
PHP 8.1.x

[herbdool]

You could have an early return of false if $patterns is null, or not a string.