Neos\Media\Browser\Controller\Module\Management\AssetController::errorAction PHP Method

    protected function errorAction()
    {
        foreach ($this->arguments->getValidationResults()->getFlattenedErrors() as $propertyPath => $errors) {
            foreach ($errors as $error) {
                $this->flashMessageContainer->addMessage($error);
            }
        }
        return parent::errorAction();
    }