Password Confirmation Widget and Validator in Symfony

$this->widgetSchema['password'] = new sfWidgetFormInputPassword(array('label' => 'Password'));
$this->widgetSchema['password_confirm'] = new sfWidgetFormInputPassword(array('label' => 'Password confirm'));
$this->validatorSchema['password'] = new sfValidatorString(array(
  'min_length' => 5
), array(
  'min_length' => 'Password too short (min 5 chars).'));
$this->validatorSchema['password_confirm'] = clone $this->validatorSchema['password'];
$this->mergePostValidator(new 
sfValidatorSchemaCompare('password',
sfValidatorSchemaCompare::EQUAL, 'password_confirm', array(),
array('invalid' => 'Passwords do not match.')));

Note: In this case password fields are not required.