Create callback for question removal

I think we may need to add the below methods to the WebformHandlerInterface

  public function createElement(array $element) {}
  public function updateElement((array $element) {}
  public function deleteElement((array $element) {}

One limitation is bulk updating elements probably can't trigger these callbacks.

When editing the element's YAML source, I am not sure I am up for writing the code for figuring which elements were created, updated, or deleted.

I figured out how to track all element CRUD operations, even when editing the YAML source.

The attached patch still needs some basic test coverage.

I applied the patch. Please download the latest dev release to review.

@bobby.gryzynger Not sure it makes sense to add theses hooks to the WebformElement plugin because most developers won't be creating their own elements or overriding existing one.

I think we can use my code to setup a custom hook_webform_update() to trigger events for elements that are created, updated, or deleted.

BTW, I think using entity hooks is the best way to "attach a handler without the user having to do so manually".

I think the below code is enough to point you in the right direction. You could easily change presave to delete. The attached patch fixes a minor issue.

/**
 * Implements hook_ENTITY_TYPE_presave().
 */
function webform_test_webform_presave(\Drupal\webform\WebformInterface $webform) {
  $elements_original = Yaml::decode($webform->getElementsOriginalRaw());
  $elements = \Drupal\Core\Serialization\Yaml::decode($webform->getElementsRaw());
  if ($elements_original != $elements) {
    $elements_original = \Drupal\webform\Utility\WebformElementHelper::getFlattened($elements_original);
    $elements = \Drupal\webform\Utility\WebformElementHelper::getFlattened($elements);

    // Handle create element.
    if ($created_elements = array_diff_key($elements, $elements_original)) {
      foreach ($created_elements as $element_key => $element) {
        drupal_set_message(t('Created @key', ['@key' => $element_key]));
      }
    }

    // Handle delete element.
    if ($deleted_elements = array_diff_key($elements_original, $elements)) {
      foreach ($deleted_elements as $element_key => $element) {
        drupal_set_message(t('Deleted @key', ['@key' => $element_key]));
      }
    }

    // Handle update element.
    foreach ($elements as $element_key => $element) {
      if (isset($elements_original[$element_key]) && $elements_original[$element_key] != $element) {
        drupal_set_message(t('Updated @key', ['@key' => $element_key]));
      }
    }
  }
}

The attached patch adds a Webform::getElementsOriginalDecoded method to correspond with Webform::getElementsDecoded which can also return FALSE if the original elements were invalid but now we can just call...

$elements_original = $webform->getElementsOriginalDecoded() ?: [];
$elements = $webform->getElementsDecoded() ?: [];

@bobby.gryzynger Can you please post a recipe for other people to learn from?

Maybe something like "How to track webform element create, update, and delete operations"

@bobby.gryzynger I can't reassign this issue to you but let's use this current issue.