如果WooCommerce single products中的内容为空，则隐藏自定义产品选项卡

<?php if ( $tabs ) : ?>

    <div class="woocommerce-tabs wc-tabs-wrapper">
        <ul class="tabs wc-tabs" role="tablist">
            <?php foreach ( $tabs as $key => $tab ) : ?>
                <li class="<?php echo esc_attr( $key ); ?>_tab" id="tab-title-<?php echo esc_attr( $key ); ?>" role="tab" aria-controls="tab-<?php echo esc_attr( $key ); ?>">
                    <a href="#tab-<?php echo esc_attr( $key ); ?>"><?php echo apply_filters( 'woocommerce_product_' . $key . '_tab_title', esc_html( $tab['title'] ), $key ); ?></a>
                </li>
            <?php endforeach; ?>
        </ul>
        <?php foreach ( $tabs as $key => $tab ) : ?>
            <div class="woocommerce-Tabs-panel woocommerce-Tabs-panel--<?php echo esc_attr( $key ); ?> panel entry-content wc-tab" id="tab-<?php echo esc_attr( $key ); ?>" role="tabpanel" aria-labelledby="tab-title-<?php echo esc_attr( $key ); ?>">
                <?php call_user_func( $tab['callback'], $key, $tab ); ?>
            </div>
        <?php endforeach; ?>
    </div>

<?php endif; ?>

<?php
    $product_content = get_the_content();
    if ( empty( $product_content ) ) {
        continue; // 隐藏自定义产品选项卡
    }
?>