function action_pre_get_comments($query) {
    $product_category = wp_get_post_terms(get_the_ID(), 'product_cat');

    if(empty($product_category) && !is_array($product_category)) {
        return $query;
    }

    if (!is_admin() && is_singular(array('product'))) {
        $args = array(
                'post_type' => 'product',
                'post_status' => 'publish',
                'ignore_sticky_posts' => 1,
                'posts_per_page' => -1,
                'tax_query' => array(
                        array(
                                'taxonomy' => 'product_cat',
                                'field' => 'term_id',
                                'terms' => $product_category[0]->term_id,
                                'operator' => 'IN'
                        ),
                ),
                'fields' => 'ids'
        );
        $products = new WP_Query($args);

        $query->query_vars['post_id'] = null;
        $query->query_vars['post__in'] = $products->posts;
    }
    return $query;
};
add_action( 'pre_get_comments', 'action_pre_get_comments', 10, 1 );




function add_sku_suffix_to_product_permalinks($slug, $post_ID, $post_status, $post_type, $post_parent, $old_slug) {
    $post_title = get_the_title($post_ID);
    $post_title = sanitize_title($post_title);

    if($post_status === 'publish' && $post_type == 'product') {
        $product_sku = get_post_meta($post_ID, '_sku', true);
        if($product_sku) {
            $slug = $post_title . '-' . $product_sku;
        }
        else {
            $slug = $post_title;
        }
    }
    return $slug;
}
add_filter('wp_unique_post_slug', 'add_sku_suffix_to_product_permalinks', 10, 6);