WC_Product_Variable_Data_Store_CPT::read_attributes │ protected │ WC 1.0

Read attributes from post meta.

Method of the class: WC_Product_Variable_Data_Store_CPT{}

Hooks from the method

Returns

null. Nothing (null).

Usage

// protected - for code of main (parent) or child class
$result = $this->read_attributes( $product );
$product(WC_Product) (required) (passed by reference — &)
Product object.

WC_Product_Variable_Data_Store_CPT::read_attributes() code WC 10.7.0

woocommerce/includes/data-stores/class-wc-product-variable-data-store-cpt.php 
protected function read_attributes( &$product ) {
	$product_id      = $product->get_id();
	$meta_attributes = get_post_meta( $product_id, '_product_attributes', true );

	if ( ! empty( $meta_attributes ) && is_array( $meta_attributes ) ) {
		$attributes   = array();
		$force_update = false;
		foreach ( $meta_attributes as $meta_attribute_key => $meta_attribute_value ) {
			$meta_value = array_merge(
				array(
					'name'         => '',
					'value'        => '',
					'position'     => 0,
					'is_visible'   => 0,
					'is_variation' => 0,
					'is_taxonomy'  => 0,
				),
				(array) $meta_attribute_value
			);

			// Maintain data integrity: WordPress 4.9 changed sanitization functions, and we update the values here so variations function correctly.
			// As per 2026, we are refactoring the updates into product-level: BC-focused (not all-in on-spot migration), optimized for performance.
			// Use-case: `_product_attributes` has data populated on WordPress pre-4.8 and containing symbols affected by the breaking changes.
			if ( $meta_value['is_variation'] && strstr( $meta_value['name'], '/' ) && sanitize_title( $meta_value['name'] ) !== $meta_attribute_key ) {
				global $wpdb;

				$child_ids = $product->get_children();
				if ( ! empty( $child_ids ) ) {
					$products_to_migrate = implode( ', ', $child_ids );
					$old_slug            = 'attribute_' . $meta_attribute_key;
					$old_meta_rows       = $wpdb->get_results(
						$wpdb->prepare(
							// phpcs:ignore WordPress.DB.PreparedSQL.InterpolatedNotPrepared
							"SELECT post_id, meta_value FROM {$wpdb->postmeta} WHERE meta_key = %s AND post_id IN ( $products_to_migrate )",
							$old_slug
						)
					);
					if ( $old_meta_rows ) {
						$new_slug = 'attribute_' . sanitize_title( $meta_value['name'] );
						foreach ( $old_meta_rows as $old_meta_row ) {
							update_post_meta( $old_meta_row->post_id, $new_slug, $old_meta_row->meta_value );
						}
					}
				}

				$force_update = true;
			}

			// Check if is a taxonomy attribute.
			if ( ! empty( $meta_value['is_taxonomy'] ) ) {
				if ( ! taxonomy_exists( $meta_value['name'] ) ) {
					continue;
				}
				$id      = wc_attribute_taxonomy_id_by_name( $meta_value['name'] );
				$options = wc_get_object_terms( $product_id, $meta_value['name'], 'term_id' );
			} else {
				$id      = 0;
				$options = wc_get_text_attributes( $meta_value['value'] );
			}

			$attribute = new WC_Product_Attribute();
			$attribute->set_id( $id );
			$attribute->set_name( $meta_value['name'] );
			$attribute->set_options( $options );
			$attribute->set_position( $meta_value['position'] );
			$attribute->set_visible( $meta_value['is_visible'] );
			$attribute->set_variation( $meta_value['is_variation'] );

			/**
			 * Filter product attribute after initialization.
			 *
			 * @since 10.6.0
			 *
			 * @param WC_Product_Attribute $attribute  The attribute object.
			 * @param array                $meta_value The meta value.
			 * @param WC_Product           $product    The product object.
			 */
			$attributes[] = apply_filters( 'woocommerce_product_read_attribute', $attribute, $meta_value, $product );
		}
		$product->set_attributes( $attributes );

		if ( $force_update ) {
			$this->update_attributes( $product, true );
		}
	}
}