php - Display a product custom field only in WooCommerce Admin single orders for Manual Orders

Question

Following Display a product custom field only in WooCommerce Admin single orders answer to my previous question, which:

1. Adds a Custom SKU Field (ArticleID)
2. Saves the Custom SKU (ArticleID) as Hidden Order Item Meta Data
3. Saves the Custom SKU (ArticleID) as Hidden Order Item Meta Data for Manual Orders

However, it seems that the last part (for Manual Orders) is causing a conflict with this following other custom code I added for Gateway Fees:

// Assign Card Gateway Percentage Fee to Wholesaler Profiles
add_action('woocommerce_cart_calculate_fees', 'sm_credit_card_fee_role_gateway' );
function sm_credit_card_fee_role_gateway( $cart ){
    if ( is_admin() && !defined('DOING_AJAX') )
        return;

    // Only on checkout page and logged in users
    if ( ! ( is_checkout() && ! is_wc_endpoint_url() ) || ! is_user_logged_in() )
        return;

    $wpuser_object = wp_get_current_user();
    $allowed_roles = array('administrator', 'default_wholesaler', 'wholesaler-non-vat-registered', 'wholesaler-ex-vat-registered', 'wholesaler-ex-non-vat-registered', 'shop_manager');

    if ( array_intersect($allowed_roles, $wpuser_object->roles) ){
        $payment_method = WC()->session->get('chosen_payment_method');

        if ( 'cardgatecreditcard' === $payment_method ){
            $percentage = 8.25;
            $description = 'Credit Card';
        }
        elseif ( 'cardgatesofortbanking' === $payment_method ){
            $percentage = 6;
            $description = 'SofortBanking';
        }
        elseif ( 'cardgategiropay' === $payment_method ){
            $percentage = 3.15;
            $description = 'GiroPay';
        }
        elseif ( 'cardgateideal' === $payment_method ){
            $percentage = 2.1;
            $description = 'iDEAL';
        }
    }
    if ( isset($percentage) ) {
        $surcharge = ($cart->cart_contents_total + $cart->shipping_total) * $percentage / 100;
        $cart->add_fee( sprintf( __('%s Fee (%s)', 'woocommerce'), $description, $percentage . '%' ), $surcharge, true );
    }
}

When I try to update or change the status of an order that has Gateway Fees applied to it, I get this Fatal Error:

So either part 3 of my SKU code needs to be written better, or my gateway fee code needs to be updated. How do I go about troubleshooting this further?

This is the Fatal Error:

Fatal error: Uncaught Error: Call to undefined method WC_Order_Item_Fee::get_product() in …/public_html/wp-content/themes/oceanwp-child/functions.php:920 
Stack trace: 
#0 …/public_html/wp-includes/class-wp-hook.php(287): action_before_save_order_item_callback(Object(WC_Order_Item_Fee)) 
#1 …/public_html/wp-includes/class-wp-hook.php(311): WP_Hook->apply_filters(NULL, Array) 
#2 …/public_html/wp-includes/plugin.php(478): WP_Hook->do_action(Array) 
#3 …/public_html/wp-content/plugins/woocommerce/includes/admin/wc-admin-functions.php(324): do_action('woocommerce_bef...', Object(WC_Order_Item_Fee)) 
#4 …/public_html/wp-content/plugins/woocommerce/includes/admin/meta-boxes/class-wc-meta-box-order-items.php(54): wc_save_order_items(6053, Array) 
#5 …/public_html/wp-includes/class-wp-hook.php(289): WC_Meta_B in …/public_html/wp-content/themes/oceanwp-child/functions.php on line 920

The line Line 920 which is part of "Save SKU "ArticleID" as Hidden Order Item Meta Data for Manual Orders":

$product = $item->get_product(); // Get the WC_Product Object

Answer 1

You need to target only line items on the last function, this way:

add_action( 'woocommerce_before_save_order_item', 'action_before_save_order_item_callback' );
function action_before_save_order_item_callback( $item ) {
    // Targeting only order item type "line_item"
    if ( $item->get_type() !== 'line_item' )
        return; // exit

    $articleid = $item->get_meta('articleid');

    if ( ! $articleid ) {
        $product = $item->get_product(); // Get the WC_Product Object
        
        // Get custom meta data from the product
        $articleid = $product->get_meta('articleid');
        
        // For product variations when the "articleid" is not defined
        if ( ! $articleid && $item->get_variation_id() > 0 ) {
            $product   = wc_get_product( $item->get_product_id() ); // Get the parent variable product
            $articleid = $product->get_meta( 'articleid' );  // Get parent product "articleid"
        }

        // Save it as custom order item (if defined for the product)        
        if ( $articleid ) {
            $item->update_meta_data( '_articleid', $articleid );
        }
    }
}

Code goes in functions.php file of the active child theme (or active theme). It should works now.

Related to this thread:

• Change order item displayed meta key label in WooCommerce admin order pages
• Display a product custom field only in WooCommerce Admin single orders
• Change order item displayed meta key label in WooCommerce admin order pages