WP_Theme_JSON::sanitize( array $input, array $valid_block_names, array $valid_element_names, array $valid_variations ): array

940	protected static function sanitize( $input, $valid_block_names, $valid_element_names, $valid_variations ) {941 942		$output = array();943 944		if ( ! is_array( $input ) ) {945			return $output;946		}947 948		// Preserve only the top most level keys.949		$output = array_intersect_key( $input, array_flip( static::VALID_TOP_LEVEL_KEYS ) );950 951		/*952		 * Remove any rules that are annotated as "top" in VALID_STYLES constant.953		 * Some styles are only meant to be available at the top-level (e.g.: blockGap),954		 * hence, the schema for blocks & elements should not have them.955		 */956		$styles_non_top_level = static::VALID_STYLES;957		foreach ( array_keys( $styles_non_top_level ) as $section ) {958			// array_key_exists() needs to be used instead of isset() because the value can be null.959			if ( array_key_exists( $section, $styles_non_top_level ) && is_array( $styles_non_top_level[ $section ] ) ) {960				foreach ( array_keys( $styles_non_top_level[ $section ] ) as $prop ) {961					if ( 'top' === $styles_non_top_level[ $section ][ $prop ] ) {962						unset( $styles_non_top_level[ $section ][ $prop ] );963					}964				}965			}966		}967 968		// Build the schema based on valid block & element names.969		$schema                 = array();970		$schema_styles_elements = array();971 972		/*973		 * Set allowed element pseudo selectors based on per element allow list.974		 * Target data structure in schema:975		 * e.g.976		 * - top level elements: `$schema['styles']['elements']['link'][':hover']`.977		 * - block level elements: `$schema['styles']['blocks']['core/button']['elements']['link'][':hover']`.978		 */979		foreach ( $valid_element_names as $element ) {980			$schema_styles_elements[ $element ] = $styles_non_top_level;981 982			if ( isset( static::VALID_ELEMENT_PSEUDO_SELECTORS[ $element ] ) ) {983				foreach ( static::VALID_ELEMENT_PSEUDO_SELECTORS[ $element ] as $pseudo_selector ) {984					$schema_styles_elements[ $element ][ $pseudo_selector ] = $styles_non_top_level;985				}986			}987		}988 989		$schema_styles_blocks   = array();990		$schema_settings_blocks = array();991 992		/*993		 * Generate a schema for blocks.994		 * - Block styles can contain `elements` & `variations` definitions.995		 * - Variations definitions cannot be nested.996		 * - Variations can contain styles for inner `blocks`.997		 * - Variation inner `blocks` styles can contain `elements`.998		 *999		 * As each variation needs a `blocks` schema but further nested1000		 * inner `blocks`, the overall schema will be generated in multiple passes.1001		 */1002		foreach ( $valid_block_names as $block ) {1003			$schema_settings_blocks[ $block ]           = static::VALID_SETTINGS;1004			$schema_styles_blocks[ $block ]             = $styles_non_top_level;1005			$schema_styles_blocks[ $block ]['elements'] = $schema_styles_elements;1006		}1007 1008		$block_style_variation_styles             = static::VALID_STYLES;1009		$block_style_variation_styles['blocks']   = $schema_styles_blocks;1010		$block_style_variation_styles['elements'] = $schema_styles_elements;1011 1012		foreach ( $valid_block_names as $block ) {1013			// Build the schema for each block style variation.1014			$style_variation_names = array();1015			if (1016				! empty( $input['styles']['blocks'][ $block ]['variations'] ) &&1017				is_array( $input['styles']['blocks'][ $block ]['variations'] ) &&1018				isset( $valid_variations[ $block ] )1019			) {