original_string: protected function validateAlias()
      {
          $field = 'alias';
          $value = $this->getSubmitted($field);
  
          if (empty($value)) {
              $this->unsetSubmitted($field);
              return null;
          }
  
          $label = $this->translation->text('Alias');
  
          if (mb_strlen($value) > 255) {
              $this->setErrorLengthRange($field, $label, 0, 255);
              return false;
          }
  
          if (preg_match('/^[A-Za-z0-9_.-]+$/', $value) !== 1) {
              $this->setErrorInvalid($field, $label);
              return false;
          }
  
          $updating = $this->getUpdating();
  
          if (isset($updating['alias']) && $updating['alias'] === $value) {
              return true; // Do not check own alias on update
          }
  
          if ($this->alias->exists($value)) {
              $this->setErrorExists($field, $label);
              return false;
          }
  
          return true;
      }
code: protected function validateAlias()
      {
          $field = 'alias';
          $value = $this->getSubmitted($field);
  
          if (empty($value)) {
              $this->unsetSubmitted($field);
              return null;
          }
  
          $label = $this->translation->text('Alias');
  
          if (mb_strlen($value) > 255) {
              $this->setErrorLengthRange($field, $label, 0, 255);
              return false;
          }
  
          if (preg_match('/^[A-Za-z0-9_.-]+$/', $value) !== 1) {
              $this->setErrorInvalid($field, $label);
              return false;
          }
  
          $updating = $this->getUpdating();
  
          if (isset($updating['alias']) && $updating['alias'] === $value) {
              return true; // Do not check own alias on update
          }
  
          if ($this->alias->exists($value)) {
              $this->setErrorExists($field, $label);
              return false;
          }
  
          return true;
      }
code_tokens: protected function validateAlias ( ) { $ field = 'alias' ; $ value = $ this -> getSubmitted ( $ field ) ; if ( empty ( $ value ) ) { $ this -> unsetSubmitted ( $ field ) ; return null ; } $ label = $ this -> translation -> text ( 'Alias' ) ; if ( mb_strlen ( $ value ) > 255 ) { $ this -> setErrorLengthRange ( $ field , $ label , 0 , 255 ) ; return false ; } if ( preg_match ( '/^[A-Za-z0-9_.-]+$/' , $ value ) !== 1 ) { $ this -> setErrorInvalid ( $ field , $ label ) ; return false ; } $ updating = $ this -> getUpdating ( ) ; if ( isset ( $ updating [ 'alias' ] ) && $ updating [ 'alias' ] === $ value ) { return true ; // Do not check own alias on update } if ( $ this -> alias -> exists ( $ value ) ) { $ this -> setErrorExists ( $ field , $ label ) ; return false ; } return true ; }
docstring: Validates an alias
  @return boolean|null
docstring_tokens: Validates an alias