WP_Theme_JSON::merge( WP_Theme_JSON $incoming )

3166	public function merge( $incoming ) {3167		$incoming_data    = $incoming->get_raw_data();3168		$this->theme_json = array_replace_recursive( $this->theme_json, $incoming_data );3169 3170		/*3171		 * Recompute all the spacing sizes based on the new hierarchy of data. In the constructor3172		 * spacingScale and spacingSizes are both keyed by origin and VALID_ORIGINS is ordered, so3173		 * we can allow partial spacingScale data to inherit missing data from earlier layers when3174		 * computing the spacing sizes.3175		 *3176		 * This happens before the presets are merged to ensure that default spacing sizes can be3177		 * removed from the theme origin if $prevent_override is true.3178		 */3179		$flattened_spacing_scale = array();3180		foreach ( static::VALID_ORIGINS as $origin ) {3181			$scale_path = array( 'settings', 'spacing', 'spacingScale', $origin );3182 3183			// Apply the base spacing scale to the current layer.3184			$base_spacing_scale      = _wp_array_get( $this->theme_json, $scale_path, array() );3185			$flattened_spacing_scale = array_replace( $flattened_spacing_scale, $base_spacing_scale );3186 3187			$spacing_scale = _wp_array_get( $incoming_data, $scale_path, null );3188			if ( ! isset( $spacing_scale ) ) {3189				continue;3190			}3191 3192			// Allow partial scale settings by merging with lower layers.3193			$flattened_spacing_scale = array_replace( $flattened_spacing_scale, $spacing_scale );3194 3195			// Generate and merge the scales for this layer.3196			$sizes_path           = array( 'settings', 'spacing', 'spacingSizes', $origin );3197			$spacing_sizes        = _wp_array_get( $incoming_data, $sizes_path, array() );3198			$spacing_scale_sizes  = static::compute_spacing_sizes( $flattened_spacing_scale );3199			$merged_spacing_sizes = static::merge_spacing_sizes( $spacing_scale_sizes, $spacing_sizes );3200 3201			_wp_array_set( $incoming_data, $sizes_path, $merged_spacing_sizes );3202		}3203 3204		/*3205		 * The array_replace_recursive algorithm merges at the leaf level,3206		 * but we don't want leaf arrays to be merged, so we overwrite it.3207		 *3208		 * For leaf values that are sequential arrays it will use the numeric indexes for replacement.3209		 * We rather replace the existing with the incoming value, if it exists.3210		 * This is the case of spacing.units.3211		 *3212		 * For leaf values that are associative arrays it will merge them as expected.3213		 * This is also not the behavior we want for the current associative arrays (presets).3214		 * We rather replace the existing with the incoming value, if it exists.3215		 * This happens, for example, when we merge data from theme.json upon existing3216		 * theme supports or when we merge anything coming from the same source twice.3217		 * This is the case of color.palette, color.gradients, color.duotone,3218		 * typography.fontSizes, or typography.fontFamilies.3219		 *3220		 * Additionally, for some preset types, we also want to make sure the3221		 * values they introduce don't conflict with default values. We do so3222		 * by checking the incoming slugs for theme presets and compare them3223		 * with the equivalent default presets: if a slug is present as a default3224		 * we remove it from the theme presets.3225		 */3226		$nodes        = static::get_setting_nodes( $incoming_data );3227		$slugs_global = static::get_default_slugs( $this->theme_json, array( 'settings' ) );3228		foreach ( $nodes as $node ) {3229			// Replace the spacing.units.3230			$path   = $node['path'];3231			$path[] = 'spacing';3232			$path[] = 'units';3233 3234			$content = _wp_array_get( $incoming_data, $path, null );3235			if ( isset( $content ) ) {3236				_wp_array_set( $this->theme_json, $path, $content );3237			}3238 3239			// Replace the presets.3240			foreach ( static::PRESETS_METADATA as $preset_metadata ) {3241				$prevent_override = $preset_metadata['prevent_override'];3242				if ( is_array( $prevent_override ) ) {3243					$prevent_override = _wp_array_get( $this->theme_json['settings'], $preset_metadata['prevent_override'] );3244				}3245