The subject function receives the following PHP notification on each execution ... if the requested product does not have attributes:
Code:
PHP Notice: Undefined property: queryFactoryResult::$fields in C:\xampp\htdocs\test\test_admin\includes\functions\general.php on line 2075
The issue is with the highlighted code since the fields array is not returned if the product has no attributes:
Code:
/**
 * Check if product has attributes
 */
  function zen_has_product_attributes($products_id, $not_readonly = 'true') {
    global $db;

    if (PRODUCTS_OPTIONS_TYPE_READONLY_IGNORED == '1' and $not_readonly == 'true') {
      // don't include READONLY attributes to determin if attributes must be selected to add to cart
      $attributes_query = "select pa.products_attributes_id
                           from " . TABLE_PRODUCTS_ATTRIBUTES . " pa left join " . TABLE_PRODUCTS_OPTIONS . " po on pa.options_id = po.products_options_id
                           where pa.products_id = '" . (int)$products_id . "' and po.products_options_type != '" . PRODUCTS_OPTIONS_TYPE_READONLY . "' limit 1";
    } else {
      // regardless of READONLY attributes no add to cart buttons
      $attributes_query = "select pa.products_attributes_id
                           from " . TABLE_PRODUCTS_ATTRIBUTES . " pa
                           where pa.products_id = '" . (int)$products_id . "' limit 1";
    }

    $attributes = $db->Execute($attributes_query);

    if ($attributes->fields['products_attributes_id'] > 0) {
      return true;
    } else {
      return false;
    }
  }
The notification can be corrected by the following change:
Code:
/**
 * Check if product has attributes
 */
  function zen_has_product_attributes($products_id, $not_readonly = 'true') {
    global $db;

    if (PRODUCTS_OPTIONS_TYPE_READONLY_IGNORED == '1' and $not_readonly == 'true') {
      // don't include READONLY attributes to determin if attributes must be selected to add to cart
      $attributes_query = "select pa.products_attributes_id
                           from " . TABLE_PRODUCTS_ATTRIBUTES . " pa left join " . TABLE_PRODUCTS_OPTIONS . " po on pa.options_id = po.products_options_id
                           where pa.products_id = '" . (int)$products_id . "' and po.products_options_type != '" . PRODUCTS_OPTIONS_TYPE_READONLY . "' limit 1";
    } else {
      // regardless of READONLY attributes no add to cart buttons
      $attributes_query = "select pa.products_attributes_id
                           from " . TABLE_PRODUCTS_ATTRIBUTES . " pa
                           where pa.products_id = '" . (int)$products_id . "' limit 1";
    }

    $attributes = $db->Execute($attributes_query);

    return !$attributes->EOF;
  }