Woocommerce添加到购物车重定向到父类别

我已经尝试了几天了，我刚刚发现了这个代码:

//This is to redirect add to cart button to restaurant page add_filter
('add_to_cart_redirect', 'redirect_to_previousCat');
function redirect_to_previousCat( $url ) {if ( isset( $_POST['add-to-cart'] ) )
{  
    $product_id = (int) apply_filters('woocommerce_add_to_cart_product_id', $_POST['add-to-cart'] );
    $terms = get_the_terms( $product_id, 'product_cat' );
    foreach($terms as $term) {
        $product_cat_slug = $term->slug;      
        break; 
    }    
    if( $product_cat_slug ){
        $url = user_trailingslashit(get_permalink() . '/restaurant/' . $product_cat_slug );    
    }  
    }
return $url;
}

/餐厅/parent-category-slug

但是代码将它重定向到/restaurant/product-category/

我真的需要一些帮助。