unregister_setting() raises a PHP warning on unknown settings

[xknown]

Starting from PHP 8.x, attempting to unregister an undefined setting results in PHP warnings: Warning: Trying to access array offset on value of type null.

unregister_setting( 'somethingrandom', 'somethingrandom' );

Trac ticket: https://core.trac.wordpress.org/ticket/57674

[hellofromTonya]

I'll mark this ticket as a php-compatibility focus to include it in the PHP 8.1 compat exclusion list.

[SergeyBiryukov]

Good catch, we already check if $wp_registered_settings[ $option_name ] is set there, so I think it makes sense to do the same for $new_allowed_options[ $option_group ].

[nicolefurlan]

I dropped this one in #core-test to hopefully get a test report so that we can include it in the 6.4 release.

[nicolefurlan]

Test Report

This report validates that the indicated patch addresses the issue.

Patch tested: ​https://github.com/WordPress/wordpress-develop/pull/4035

Environment

• OS: macOS Ventura 13.4.1
• PHP: 8.2.11
• WordPress: trunk

Actual Results

• ✅ Issue resolved with patch.
• ✅ Unit tests pass.

Additional Notes

• I used WP CLI via npm run env:cli to test this and verified that when executing unregister_setting( 'somethingrandom', 'somethingrandom' ); on the CLI, the Notice: Trying to access array offset on value of type null in /var/www/src/wp-includes/option.php on line 2821 notice appears without the patch, and disappears after applying the patch.
• I ran phpunit on registration.php via npm run test:php --debug tests/phpunit/tests/option/registration.php and verified that all unit tests pass in registration.php.

[shailu25]

Test Report

Patch Tested: ​https://github.com/WordPress/wordpress-develop/pull/4035

Environment:

WordPress - 6.4-beta2
OS - Windows
Browser - Chrome
Theme: Twenty Nineteen
PHP - 8.1.17
Active Plugin - None

Actual Results:

• ✅ After Applying Patch PHP warnings is Resolved. Patch is Working as Expected.

Screenshots :

Before Patch: ​https://prnt.sc/2fFQlHqLDN3X
After Patch : ​https://prnt.sc/hjkRvmewxIgl

[nicolefurlan]

We have a couple of passing test reports here. Does this seem ready for commit? (cc @hellofromTonya, @SergeyBiryukov)

[hellofromTonya]

Thanks for the ping (and reminder) @nicolefurlan. The source code fix LGTM and is ready for commit. I'm not sure about the test, but am reviewing.

I'll set myself as owner for the review and commit.

[hellofromTonya]

The patch ​https://github.com/WordPress/wordpress-develop/pull/4035 is ready for commit. Will prep the commit in time for 6.4 Beta 3.

[hellofromTonya]

The patch fixes 2 different PHP Warning|Notice scenarios:

1. When the global $new_allowed_options is null, fixes raising Trying to access array offset on value of type null PHP Notice (PHP 7.4) | Warning (on PHP 8).

2. When the global $new_allowed_options is an array and the setting group key does not exist, fixes raising "Undefined index: unknown_setting_group" PHP Notice (PHP 7) | Warning (on PHP 8).

See both scenarios in action ​https://3v4l.org/oeFUJ.

[hellofromTonya]

In 56817:

Options, Meta APIs: Check setting group exists before search in unregister_setting().

Checks if the given $option_group exists before searching for the $option_name. Sets the $pos to false, as array_search() returns false if the option name (needle) does not exist.

This changeset fixes 2 different PHP Warning|Notice scenarios:

1. When the global $new_allowed_options is null, fixes raising Trying to access array offset on value of type null PHP Notice (PHP 7.4) | Warning (on PHP 8).

2. When the global $new_allowed_options is an array and the setting group key does not exist, fixes raising "Undefined index: unknown_setting_group" PHP Notice (PHP 7) | Warning (on PHP 8).

For both scenarios, the array_search() is skipped and the $pos is set to a default of false, i.e. which is the value returned when array_search() is unsuccessful.

Props xknown, hellofromTonya, nicolefurlan, oglekler, SergeyBiryukov, shailu25.
Fixes #57674.

Committed via https://core.trac.wordpress.org/changeset/56817.