FIX: WooCommerce generates non appropriate rewrite slug for product attributes with non latin language slug.

wc-fix-pa-rewrite-slug.php

<?php
/**
 * @wordpress-plugin
 * Plugin Name:       FIX: WooCommerce generates non appropriate rewrite slug for product attributes with CJK language slug.
 * Depends:           WooCommerce
 * Plugin URI:        
 * Description:       
 * Version:           1.0.0
 * Author:            chrono-meter@gmx.net
 * Author URI:        mailto:chrono-meter@gmx.net
 * License:           GPL-2.0+
 * License URI:       http://www.gnu.org/licenses/gpl-2.0.txt
 *
 * @see WC_Post_Types::register_taxonomies
 * @link https://github.com/woocommerce/woocommerce/blob/master/includes/class-wc-post-types.php
 */

defined( 'ABSPATH' ) or exit;


add_action( 'init', function() {
    if ( !defined( 'WC_PLUGIN_FILE' ) ) return;

    $permalinks = wc_get_permalink_structure();
    $attribute_taxonomies  = wc_get_attribute_taxonomies();

    if ( $attribute_taxonomies ) {
        foreach ( $attribute_taxonomies as $tax ) {
            $name = wc_attribute_taxonomy_name( $tax->attribute_name );
            add_filter( "woocommerce_taxonomy_args_{$name}", function($taxonomy_data) use($permalinks, $tax) {
                if ( !empty( $taxonomy_data['rewrite'] ) ) {
                    $taxonomy_data['rewrite']['slug'] = trailingslashit( $permalinks['attribute_rewrite_slug'] ) . rawurldecode( sanitize_title( $tax->attribute_name ) );
                }
                return $taxonomy_data;
            } );
        }
    }
}, 0 );