I want to create a filter text module for drupal 8.


 * @file
 * Contains \Drupal\emtfilter\Plugin\Filter\emtfilter.

namespace Drupal\emtfilter\Plugin\Filter;

use Drupal\Core\Form\FormStateInterface;
use Drupal\filter\FilterProcessResult;
use Drupal\filter\Plugin\FilterBase;

 * Text filter for highlighting PHP source code.
 * @Filter(
 *   id = "emtfilter",
 *   module = "emtfilter",
 *   title = @Translation("Tipograf"),
 *   description = @Translation("Tipograf"),
 *   type = Drupal\filter\Plugin\FilterInterface::TYPE_HTML_RESTRICTOR,
 * )
class emtfilter extends FilterBase { 

   * {@inheritdoc}
  public function tips($long = FALSE) {
    if ($long) {
      return t('text1r-');
    else {
      return t('text2r-');

   * {@inheritdoc}
  public function process($text, $langcode) {
        return new FilterProcessResult($text);

After clearing cashe everything is ok. But when I visit some forms with textfields second time, Drupal generates this error:

Notice: _filter_tips(): The script tried to execute a method or access a property of an incomplete object. Please ensure that the class definition "Drupal\emtfilter\Plugin\Filter\emtfilter" of the object you are trying to operate on was loaded before unserialize() gets called or provide a __autoload() function to load the class definition in _filter_tips() (line 350 of core/modules/filter/filter.module).
_filter_tips('full_html', ) (Line: 378)
template_preprocess_filter_guidelines(Array, 'filter_guidelines', Array) (Line: 293)

And my tips disappear. What am I do wrong?

  • It's probably the use of t(). Can you change to $this->t?
    – mradcliffe
    Apr 24, 2016 at 17:02
  • I tried - all the same. This is a problem with cashe, as I think. In the first launch it works properly, including translation.
    – Crantisz
    Apr 24, 2016 at 17:34

1 Answer 1


I made a mistake in the letter case in the class file (emtFilter.php -> emtfilter.php)

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