protected function read_attributes( &$product ) {
		$meta_attributes = get_post_meta( $product->get_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. 4.9 changed sanitization functions - update the values here so variations function correctly.
				if ( $meta_value['is_variation'] && strstr( $meta_value['name'], '/' ) && sanitize_title( $meta_value['name'] ) !== $meta_attribute_key ) {
					global $wpdb;

					$old_slug      = 'attribute_' . $meta_attribute_key;
					$new_slug      = 'attribute_' . sanitize_title( $meta_value['name'] );
					$old_meta_rows = $wpdb->get_results( $wpdb->prepare( "SELECT post_id, meta_value FROM {$wpdb->postmeta} WHERE meta_key = %s;", $old_slug ) ); // WPCS: db call ok, cache ok.

					if ( $old_meta_rows ) {
						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->get_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'] );
				$attributes[] = $attribute;
			}
			$product->set_attributes( $attributes );

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