Inconsistency between EntityTypeInterface ::getHandlerClass() and ::hasHandlerClass()

Make sense , LGTM.

+++ b/core/lib/Drupal/Core/Entity/EntityTypeInterface.php
@@ -168,11 +168,13 @@ public function hasHandlerClass($handler_type, $nested = FALSE);
+   * @param bool $nested
+   *   (optional) If this handler has a nested definition. Defaults to FALSE.

So this is not a boolean. I was wondering what on earth does nested mean...

But it's normally a string when it is actually used... for example:

$operation = $entity->getEntityType()->hasHandlerClass('form', 'add') ? 'add' : 'default';

Nested handlers are like the form and route_provider ones below...

 *   handlers = {
 *     "storage" = "Drupal\node\NodeStorage",
 *     "storage_schema" = "Drupal\node\NodeStorageSchema",
 *     "view_builder" = "Drupal\node\NodeViewBuilder",
 *     "access" = "Drupal\node\NodeAccessControlHandler",
 *     "views_data" = "Drupal\node\NodeViewsData",
 *     "form" = {
 *       "default" = "Drupal\node\NodeForm",
 *       "delete" = "Drupal\node\Form\NodeDeleteForm",
 *       "edit" = "Drupal\node\NodeForm",
 *       "delete-multiple-confirm" = "Drupal\node\Form\DeleteMultiple"
 *     },
 *     "route_provider" = {
 *       "html" = "Drupal\node\Entity\NodeRouteProvider",
 *     },
 *     "list_builder" = "Drupal\node\NodeListBuilder",
 *     "translation" = "Drupal\node\NodeTranslationHandler"
 *   },

Here I have tried to made changes as per comment #4.

Well it's string|false and we should update \Drupal\Core\Entity\EntityTypeInterface::hasHandlerClass() too.

LGTM!

Committed and pushed fd8c922277 to 9.0.x and e6fcece5ee to 8.9.x. Thanks!

As the only implementation in core has the param even though it's not on the interface I think this is an okay under the 1-1 interface to class rule.

I just closed #2203357: Inconstancies in getHandlerClass and hasHandlerClass as a duplicate of this which is unfortunate as it was opened earlier than this, in 2014. A good reminder to all of us to search for existing issues.