yii\base\Model::isAttributeRequired PHP Метод

    public function isAttributeRequired($attribute)
    {
        foreach ($this->getActiveValidators($attribute) as $validator) {
            if ($validator instanceof RequiredValidator && $validator->when === null) {
                return true;
            }
        }
        return false;
    }

 /**
  * @param \yii\base\Model $model
  * @param array[]         $fields
  *
  * @return bool
  */
 public static function hasRequiredFields($model, $fields)
 {
     foreach ($fields as $column) {
         if (!is_array($column)) {
             if ($column instanceof ActiveField && $model->isAttributeRequired($column->attribute)) {
                 return true;
             }
             continue;
         }
         foreach ($column as $row) {
             if (!is_array($row)) {
                 if ($row instanceof ActiveField && $model->isAttributeRequired($row->attribute)) {
                     return true;
                 }
                 continue;
             }
             if (static::hasRequiredFields($model, $row)) {
                 return true;
             }
         }
     }
     return false;
 }