WP_Theme_JSON: preserve valid non-preset settings when KSES filters are active

[ramonjd]

A PR to sync WordPress/gutenberg#73452

Problem

When KSES filters are active (via add_action( 'init', 'kses_init_filters' )), valid non-preset settings in Global Styles are being incorrectly filtered out. Specifically:

• lightbox.enabled and lightbox.allowEditing for Image blocks

The issue occurs because remove_insecure_settings() only preserved:

1. Presets (from PRESETS_METADATA)
2. Indirect CSS properties (from INDIRECT_PROPERTIES_METADATA)

All other valid settings were being stripped, even though they're defined in VALID_SETTINGS and are safe scalar values or arrays.

Related Issue: WordPress/gutenberg#73157

Solution

Added a new preserve_valid_settings() method and SAFE_SETTINGS const that work to preserves valid settings.

Testing Instructions

Manual Testing

1. Enable KSES filters:

   add_action( 'init', 'kses_init_filters' );

   Add this to your theme's functions.php or a plugin.

2. Test Image Block Lightbox Settings:

   • Go to Appearance > Editor > Styles
   • Navigate to Blocks > Image
   • Open the Settings panel
   • Toggle the "Enlarge on click" (lightbox) setting
   • Save the changes
   • Expected: The setting should persist after saving and page reload
   • Before fix: The setting would revert after saving

3. Test Other Valid Settings:

   • Try changing other valid settings in Global Styles (e.g., layout settings, spacing settings)
   • Save and verify they persist
   • Expected: All valid settings should be preserved

Trac ticket: https://core.trac.wordpress.org/ticket/64280

---

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[westonruter]

This seems like an opportunity to supply a more specific type for the $path parameter, like array<string|int>:

Suggested change

	* @param array $input Input settings to process.
	* @param array $output Output settings array (passed by reference).
	* @param array $schema Schema to validate against (typically VALID_SETTINGS).
	* @param array $path Current path in the schema (for recursive calls).
	* @param array $input Input settings to process.
	* @param array $output Output settings array (passed by reference).
	* @param array $schema Schema to validate against (typically VALID_SETTINGS).
	* @param array<string|int> $path Current path in the schema (for recursive calls).

At first I was thinking string[], but in looking at _wp_array_set(), it has this logic:

wordpress-develop/src/wp-includes/functions.php

Lines 5171 to 5178 in a107147

	foreach ( $path as $path_element ) {
	if (
	! is_string( $path_element ) && ! is_integer( $path_element ) &&
	! is_null( $path_element )
	) {
	return;
	}
	}

Curiously, there is no _doing_it_wrong() here. Also curious is that that null is apparently allowed among the $path array? This seems wrong.

[ramonjd]

Good spotting. yeah it seems weird that $path = array('a', null, 'b') is allowed.

Looks like the tests don't cover it either

https://github.com/WordPress/wordpress-develop/blob/a1071476c73e110d214b1c25cba0b27ebb506386/tests/phpunit/tests/functions/wpArraySet.php