Issue #2579187 by plach, mkalkbrenner: Revert to an older entity revision with...

Issue #2579187 by plach, mkalkbrenner: Revert to an older entity revision with less translations leads to fatal error caused by EntityStorageException

core/lib/Drupal/Core/Entity/ContentEntityStorageBase.php

@@ -336,7 +336,7 @@ protected function invokeTranslationHooks(ContentEntityInterface $entity) {
         $this->invokeHook('translation_insert', $entity->getTranslation($langcode));
       }
       elseif (!isset($translations[$langcode]) && isset($original_translations[$langcode])) {
-        $this->invokeHook('translation_delete', $entity->getTranslation($langcode));
+        $this->invokeHook('translation_delete', $entity->original->getTranslation($langcode));
       }
     }
   }

core/modules/system/src/Tests/Entity/EntityRevisionTranslationTest.php

@@ -57,4 +57,39 @@ public function testNewRevisionAfterTranslation() {
     $this->assertTrue($this->reloadEntity($entity)->getRevisionId() > $old_rev_id, 'The entity from the storage has a newer revision id.');
   }
 
+  /**
+   * Tests if the translation object has the right revision id after new revision.
+   */
+  public function testRevertRevisionAfterTranslation() {
+    $user = $this->createUser();
+    $storage = $this->entityManager->getStorage('entity_test_mulrev');
+
+    // Create a test entity.
+    $entity = EntityTestMulRev::create([
+      'name' => $this->randomString(),
+      'user_id' => $user->id(),
+      'language' => 'en',
+    ]);
+    $entity->save();
+    $old_rev_id = $entity->getRevisionId();
+
+    $translation = $entity->addTranslation('de');
+    $translation->setNewRevision();
+    $translation->save();
+
+    $entity = $this->reloadEntity($entity);
+
+    $this->assertTrue($entity->hasTranslation('de'));
+
+    $entity = $storage->loadRevision($old_rev_id);
+
+    $entity->setNewRevision();
+    $entity->isDefaultRevision(TRUE);
+    $entity->save();
+
+    $entity = $this->reloadEntity($entity);
+
+    $this->assertFalse($entity->hasTranslation('de'));
+  }
+
 }