How to hide out of stock products from Cross-sells and Upsells products in WooCommerce?

I have some products and I have setup some cross sell and up-selling products. But there is a case when cross-selling products are out of stock. What I need to place into functions.php in order to display only available crosselling and upselling products?

Solution

I checked if there are any hooks available to modify the products to show but I didn't find it. I believe the only solution is to modify the respective templates.

Find them here:

/woocommerce/single-product/up-sells.php
/woocommerce/cart/cross-sells.php

A control will be added in the loop of each Upsells and Cross-sells template to hide each product that:

it is out of stock
and does not allow backorders

The new templates will be copied into your active child theme.

CROSS-SELLS

You will need to add the following line as the first expression within the foreach:

<?php if ( ! $cross_sell->is_in_stock() && ! $cross_sell->backorders_allowed() ) : continue; endif; ?>

The complete page will be:

<?php
/**
 * Cross-sells
 *
 * This template can be overridden by copying it to yourtheme/woocommerce/cart/cross-sells.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 4.4.0
 */

defined( 'ABSPATH' ) || exit;

if ( $cross_sells ) : ?>

    <div class="cross-sells">
        <?php
        $heading = apply_filters( 'woocommerce_product_cross_sells_products_heading', __( 'You may be interested in&hellip;', 'woocommerce' ) );

        if ( $heading ) :
            ?>
            <h2><?php echo esc_html( $heading ); ?></h2>
        <?php endif; ?>

        <?php woocommerce_product_loop_start(); ?>

            <?php foreach ( $cross_sells as $cross_sell ) : ?>

                <?php if ( ! $cross_sell->is_in_stock() && ! $cross_sell->backorders_allowed() ) : continue; endif; ?>

                <?php
                    $post_object = get_post( $cross_sell->get_id() );

                    setup_postdata( $GLOBALS['post'] =& $post_object ); // phpcs:ignore WordPress.WP.GlobalVariablesOverride.Prohibited, Squiz.PHP.DisallowMultipleAssignments.Found

                    wc_get_template_part( 'content', 'product' );
                ?>

            <?php endforeach; ?>

        <?php woocommerce_product_loop_end(); ?>

    </div>
    <?php
endif;

wp_reset_postdata();

UPSELLS

You will need to add the following line as the first expression within the foreach:

<?php if ( ! $upsell->is_in_stock() && ! $upsell->backorders_allowed() ) : continue; endif; ?>

The complete page will be:

<?php
/**
 * Single Product Up-Sells
 *
 * This template can be overridden by copying it to yourtheme/woocommerce/single-product/up-sells.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     3.0.0
 */

if ( ! defined( 'ABSPATH' ) ) {
    exit;
}

if ( $upsells ) : ?>

    <section class="up-sells upsells products">
        <?php
        $heading = apply_filters( 'woocommerce_product_upsells_products_heading', __( 'You may also like&hellip;', 'woocommerce' ) );

        if ( $heading ) :
            ?>
            <h2><?php echo esc_html( $heading ); ?></h2>
        <?php endif; ?>

        <?php woocommerce_product_loop_start(); ?>

            <?php foreach ( $upsells as $upsell ) : ?>

                <?php if ( ! $upsell->is_in_stock() && ! $upsell->backorders_allowed() ) : continue; endif; ?>

                <?php
                $post_object = get_post( $upsell->get_id() );

                setup_postdata( $GLOBALS['post'] =& $post_object ); // phpcs:ignore WordPress.WP.GlobalVariablesOverride.Prohibited, Squiz.PHP.DisallowMultipleAssignments.Found

                wc_get_template_part( 'content', 'product' );
                ?>

            <?php endforeach; ?>

        <?php woocommerce_product_loop_end(); ?>

    </section>

    <?php
endif;

wp_reset_postdata();

The code has been tested and works.