Add purge queue static cache to avoid multiple processing of same entities

Closes #3388540

src/Hook/EntityHooks.php

@@ -15,6 +15,13 @@ use Drupal\entity_reference_revisions\Plugin\Field\FieldType\EntityReferenceRevi
  */
 final class EntityHooks {
 
+  /**
+   * The processed entities cache.
+   *
+   * @var array
+   */
+  protected static array $queuedEntities = [];
+
   /**
    * Constructor of the entity hooks service.
    */
@@ -24,6 +31,29 @@ final class EntityHooks {
     protected QueueFactory $queueFactory,
   ) {}
 
+  /**
+   * Check that a specific entity has been already added to the purger queue.
+   *
+   * @param string $key
+   *   Key of the entity to check if added to queue.
+   *
+   * @return bool
+   *   TRUE if the entity has already been added to the queue, FALSE otherwise.
+   */
+  public static function isQueued($key): bool {
+    return isset(EntityHooks::$queuedEntities[$key]);
+  }
+
+  /**
+   * Indicate that an entity has been added to the purger queue.
+   *
+   * @param string $key
+   *   The key of the entity added to the purger queue.
+   */
+  public static function addToQueue($key) {
+    EntityHooks::$queuedEntities[$key] = TRUE;
+  }
+
   /**
    * Implements hook_entity_delete() and hook_entity_revision_delete().
    *
@@ -36,7 +66,9 @@ final class EntityHooks {
     if (!$entity instanceof FieldableEntityInterface) {
       return;
     }
-
+    if (self::isQueued($entity->getEntityTypeId() . '_' . $entity->id())) {
+      return;
+    }
     foreach ($entity->getFieldDefinitions() as $field_name => $field_definition) {
       $field_class = $this->fieldTypeManager->getPluginClass($field_definition->getType());
       if ($field_class == EntityReferenceRevisionsItem::class || is_subclass_of($field_class, EntityReferenceRevisionsItem::class)) {
@@ -63,10 +95,14 @@ final class EntityHooks {
           }
           $entity_ids = array_unique($entity_ids);
           foreach ($entity_ids as $revision_id => $entity_id) {
-            $this->queueFactory->get('entity_reference_revisions_orphan_purger')->createItem([
-              'entity_id' => $entity_id,
-              'entity_type_id' => $target_entity_type_id,
-            ]);
+            $entity_queue_key = $target_entity_type_id . '_' . $entity_id;
+            if (!self::isQueued($entity_queue_key)) {
+              $this->queueFactory->get('entity_reference_revisions_orphan_purger')->createItem([
+                'entity_id' => $entity_id,
+                'entity_type_id' => $target_entity_type_id,
+              ]);
+              self::addToQueue($entity_queue_key);
+            }
           }
         }
       }