WooCommerce Error debug file : Invalid argument supplied for foreach()

Question

1° I use WooCommerce V.4.7.0

2° In the Release V.4.6.1 i didn't see this happen

3° Always when i place a order, i get this error message in the debug.log file

4° Why this happens and how can i fix that please?

Error Message in the debug.log file:

[20-Nov-2020 23:58:31 UTC] PHP Warning:  Invalid argument supplied for foreach() 
in C:\xampppserver2\htdocs\mrdigital\wp-content\themes\astra-child\woocommerce\order\order-details.php 
on line 82

[21-Nov-2020 00:02:08 UTC] PHP Warning:  Invalid argument supplied for foreach() 
in C:\xampppserver2\htdocs\mrdigital\wp-content\themes\astra-child\woocommerce\order\order-details.php 
on line 82

This is the line 82

foreach ( $order->get_order_item_totals() as $key => $total ) {

This is my template file - woocommerce/order/order-details.php

<?php
/**
 * Order details
 *
 * This template can be overridden by copying it to yourtheme/woocommerce/order/order-details.php.
 *
 * HOWEVER, on occasion WooCommerce will need to update template files and you
 * (the theme developer) will need to copy the new files to your theme to
 * maintain compatibility. We try to do this as little as possible, but it does
 * happen. When this occurs the version of the template file will be bumped and
 * the readme will list any important changes.
 *
 * @see     https://docs.woocommerce.com/document/template-structure/
 * @package WooCommerce\Templates
 * @version 4.6.0
 */

defined( 'ABSPATH' ) || exit;

$order = wc_get_order( $order_id ); // phpcs:ignore WordPress.WP.GlobalVariablesOverride.Prohibited

if ( ! $order ) {
    return;
}

$order_items           = $order->get_items( apply_filters( 'woocommerce_purchase_order_item_types', 'line_item' ) );
$show_purchase_note    = $order->has_status( apply_filters( 'woocommerce_purchase_note_order_statuses', array( 'completed', 'processing' ) ) );
$show_customer_details = is_user_logged_in() && $order->get_user_id() === get_current_user_id();
$downloads             = $order->get_downloadable_items();
$show_downloads        = $order->has_downloadable_item() && $order->is_download_permitted();

if ( $show_downloads ) {
    wc_get_template(
        'order/order-downloads.php',
        array(
            'downloads'  => $downloads,
            'show_title' => true,
        )
    );
}
?>
<section class="woocommerce-order-details">
    <?php do_action( 'woocommerce_order_details_before_order_table', $order ); ?>

    <h2 class="woocommerce-order-details__title"><?php esc_html_e( 'Order details', 'woocommerce' ); ?></h2>

    <table class="woocommerce-table woocommerce-table--order-details shop_table order_details">

        <thead>
            <tr>
                <th class="woocommerce-table__product-name product-name"><?php esc_html_e( 'Product', 'woocommerce' ); ?></th>
                <th class="woocommerce-table__product-table product-total"><?php esc_html_e( 'Total', 'woocommerce' ); ?></th>
            </tr>
        </thead>

        <tbody>
            <?php
            do_action( 'woocommerce_order_details_before_order_table_items', $order );

            foreach ( $order_items as $item_id => $item ) {
                $product = $item->get_product();

                wc_get_template(
                    'order/order-details-item.php',
                    array(
                        'order'              => $order,
                        'item_id'            => $item_id,
                        'item'               => $item,
                        'show_purchase_note' => $show_purchase_note,
                        'purchase_note'      => $product ? $product->get_purchase_note() : '',
                        'product'            => $product,
                    )
                );
            }

            do_action( 'woocommerce_order_details_after_order_table_items', $order );
            ?>
        </tbody>

        <tfoot>
            <?php
            foreach ( $order->get_order_item_totals() as $key => $total ) {
                ?>
                    <tr>
                        <th scope="row"><?php echo esc_html( $total['label'] ); ?></th>
                        <td><?php echo ( 'payment_method' === $key ) ? esc_html( $total['value'] ) : wp_kses_post( $total['value'] ); // phpcs:ignore WordPress.Security.EscapeOutput.OutputNotEscaped ?></td>
                    </tr>
                    <?php
            }
            ?>
            <?php if ( $order->get_customer_note() ) : ?>
                <tr>
                    <th><?php esc_html_e( 'Note:', 'woocommerce' ); ?></th>
                    <td><?php echo wp_kses_post( nl2br( wptexturize( $order->get_customer_note() ) ) ); ?></td>
                </tr>
            <?php endif; ?>
        </tfoot>
    </table>

    <?php do_action( 'woocommerce_order_details_after_order_table', $order ); ?>
</section>

<?php
/**
 * Action hook fired after the order details.
 *
 * @since 4.4.0
 * @param WC_Order $order Order data.
 */
do_action( 'woocommerce_after_order_details', $order );

if ( $show_customer_details ) {
    wc_get_template( 'order/order-details-customer.php', array( 'order' => $order ) );
}

Answer 1

Seems like at some point that file may get loaded when there are no totals yet. May want to conditionally check for them to avoid the Error message. You can save the totals to a varibale then check to make sure they are not empty and are an array like below:

<?php
// save totals to variable
$totals = $order->get_order_item_totals();

// only loop and display if an array and not empty
if (is_array($totals) && !empty($totals)) {
  foreach ( $totals as $key => $total ) {
      ?>
          <tr>
              <th scope="row"><?php echo esc_html( $total['label'] ); ?></th>
              <td><?php echo ( 'payment_method' === $key ) ? esc_html( $total['value'] ) : wp_kses_post( $total['value'] ); // phpcs:ignore WordPress.Security.EscapeOutput.OutputNotEscaped ?></td>
          </tr>
          <?php
  }
}
?>