title: Woocommerce - Get variation SKU from Bundled Products
body: <p>I use WooCommerce with a Bundled Products plugin to display a page where people can choose options to configure a product. Each option is a product with variations. To get the variations from all 4 products I use the code below. Which used to work fine until I upgraded to WC 3 (oops). Now I get an error that the sku is empty. Do I need to change the way I get the SKU from the products?</p>
  
  <pre><code>   do_action( 'woocommerce_before_bundled_items', $product );
  
  foreach ( $bundled_items as $bundled_item ) {
  
      /**
       * 'woocommerce_bundled_item_details' hook
       *
       * @hooked wc_pb_template_bundled_item_details_wrapper_open  -   0
       * @hooked wc_pb_template_bundled_item_thumbnail             -   5
       * @hooked wc_pb_template_bundled_item_details_open          -  10
       * @hooked wc_pb_template_bundled_item_title                 -  15
       * @hooked wc_pb_template_bundled_item_description           -  20
       * @hooked wc_pb_template_bundled_item_product_details       -  25
       * @hooked wc_pb_template_bundled_item_details_close         -  30
       * @hooked wc_pb_template_bundled_item_details_wrapper_close - 100
       */
      do_action( 'woocommerce_bundled_item_details', $bundled_item, $product );
   $variations = $bundled_item-&gt;get_product_variations();
   foreach($variations as $variation) {
      if($variation['sku'] == 'colors') {
        $bi['colors'] = $bundled_item;
        continue 2;
      }
      if($variation['sku'] == 'material') {
        $bi['material'] = $bundled_item;
        continue 2;
      }
      if($variation['sku'] == 'corners') {
        $bi['corners'] = $bundled_item;
        continue 2;
      }
      if($variation['sku'] == 'text') {
        $bi['text'] = $bundled_item;
        continue 2;
      }
   }
      do_action( 'woocommerce_after_bundled_items', $product );
  
  }
  </code></pre>