I am currently building a module that parses raw HTML into a webform using YAML, however I am running into an issue where the name='SomeName' on form elements is causing an error in the YAML keys.

The form relies on the name attribute in order to accurately map the data so I need it to be case insensitive. I can force a save programmatically with

$webform = new \Drupal\webform\Entity\Webform::create(
// stuff here


However when someone attempts to edit the form in the UI and saves, there is an error preventing save that comes from docroot/modules/contrib/webform/src/WebformEntityElementsValidator.php

This error prevents saving due to casing errors.
The element key contact_Name on line 1 must contain only lowercase letters, numbers, and underscores.

The element key contact_Name on line 1 must contain only lowercase letters, numbers, and underscores.

I have tried

function MYMODULE_form_alter(&$form, \Drupal\Core\Form\FormStateInterface $form_state, $form_id) {
  $forms_array = ['webform_ui_element_form', 'webform_source_form'];
  if (in_array($form_id, $forms_array)) {
    $form['actions']['submit']['#limit_validation_errors'] = [];
    $form['actions']['submit']['#_validate_form'] = FALSE;


However it seems that for some reason this prevents saving a new element.

Any help is appreciated.

  • 1
    The error is coming \Drupal\webform\WebformEntityElementsValidator. You would need to override this service and remove the validation rule.
    – jrockowitz
    Jun 12, 2019 at 14:13
  • This is what I've been missing. I don't know why I couldn't figure it out before. Thank you!
    – JDDoesDev
    Jun 12, 2019 at 14:36
  • 1
    I just learned how to use service decorators. This is might be the best approach to tweaking/altering the WebformEntityElementsValidator service. phase2technology.com/blog/using-symfony-service
    – jrockowitz
    Jun 12, 2019 at 20:38

1 Answer 1


I was able to achieve this, thanks to some guidance in the comments, by overriding a service.

This involved work in two custom module files. The first was modules/custom/mymodule/src/MymoduleFormParserServiceProvider.php

Within that file I used ::alter to alter which class is called for a particular service.


namespace Drupal\mymodule;

use Drupal\Core\DependencyInjection\ServiceProviderBase;
use Drupal\Core\DependencyInjection\ServiceProviderInterface;
use Drupal\Core\DependencyInjection\ContainerBuilder;

 * Replace Webform validator service.
class MymoduleServiceProvider extends ServiceProviderBase implements ServiceProviderInterface {

   * {@inheritdoc}
  public function alter(ContainerBuilder $container) {
    $definition = $container->getDefinition('webform.elements_validator');


What this does is tell Drupal that when the webform.elements_validator service is called, use the MymoduleWebformElementsValidator class instead.

The second piece of the puzzle was to create that class. I did that by extending the original class WebformEntityElementsValidator with my own MymoduleWebformElementsValidator class and doing the logic there. That way I was able to keep most of the validation from the original, but make the changes to the validate method that were needed.

I was able to find many of the answers after googling override service thanks to the comment on the question by @jrockowitz

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