ACFW – Fix for fatal error on Add products tab with permanently deleted products

  $guard = function( $add_products ) {

      if ( ! is_array( $add_products ) ) {

          return $add_products;

      }

      return array_values( array_filter( $add_products, function( $item ) {

          return ! empty( $item['product_id'] ) && wc_get_product( $item['product_id'] ) !== false;

      } ) );

  };

  add_filter( 'acfwp_coupon_get_add_products_data', $guard, 9 );

  add_filter( 'acfwp_sanitize_add_products_data',   $guard, 9 );