Issue #2507967 by tim.plunkett:...

Issue #2507967 by tim.plunkett: \Drupal\Core\Entity\Controller\EntityViewController::buildTitle() assumes the  is in the render array

core/lib/Drupal/Core/Entity/Controller/EntityViewController.php

@@ -105,6 +105,7 @@ public function view(EntityInterface $_entity, $view_mode = 'full', $langcode =
 
     $page['#pre_render'][] = [$this, 'buildTitle'];
     $page['#entity_type'] = $_entity->getEntityTypeId();
+    $page['#' . $page['#entity_type']] = $_entity;
 
 
     return $page;

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

@@ -34,9 +34,7 @@ protected function setUp() {
     parent::setUp();
     // Create some dummy entity_test entities.
     for ($i = 0; $i < 2; $i++) {
-      $random_label = $this->randomMachineName();
-      $data = array('bundle' => 'entity_test', 'name' => $random_label);
-      $entity_test = $this->container->get('entity.manager')->getStorage('entity_test')->create($data);
+      $entity_test = $this->createTestEntity('entity_test');
       $entity_test->save();
       $this->entities[] = $entity_test;
     }
@@ -116,4 +114,31 @@ public function testFieldItemAttributes() {
     $this->assertTrue($xpath, 'The field item attributes from both modules have been found in the rendered output of the field.');
   }
 
+  /**
+   * Tests that a view builder can successfully override the view builder.
+   */
+  public function testEntityViewControllerViewBuilder() {
+    $entity_test = $this->createTestEntity('entity_test_view_builder');
+    $entity_test->save();
+    $this->drupalGet('entity_test_view_builder/' . $entity_test->id());
+    $this->assertText($entity_test->label());
+  }
+
+  /**
+   * Creates an entity for testing.
+   *
+   * @param string $entity_type
+   *   The entity type.
+   *
+   * @return \Drupal\Core\Entity\EntityInterface
+   *   The created entity.
+   */
+  protected function createTestEntity($entity_type) {
+    $data = array(
+      'bundle' => $entity_type,
+      'name' => $this->randomMachineName(),
+    );
+    return $this->container->get('entity.manager')->getStorage($entity_type)->create($data);
+  }
+
 }

core/modules/system/tests/modules/entity_test/entity_test.routing.yml

@@ -76,5 +76,12 @@ entity.user_role.test_operation:
   requirements:
     _access: 'TRUE'
 
+entity.entity_test_view_builder.canonical:
+  path: '/entity_test_view_builder/{entity_test_view_builder}'
+  defaults:
+    _entity_view: 'entity_test_view_builder'
+  requirements:
+    _access: 'TRUE'
+
 route_callbacks:
   - '\Drupal\entity_test\Routing\EntityTestRoutes::routes'

core/modules/system/tests/modules/entity_test/src/Entity/EntityTestViewBuilder.php

+<?php
+
+/**
+ * @file
+ * Contains \Drupal\entity_test\Entity\EntityTestViewBuilder.
+ */
+
+namespace Drupal\entity_test\Entity;
+
+/**
+ * Test entity class for testing a view builder.
+ *
+ * @ContentEntityType(
+ *   id = "entity_test_view_builder",
+ *   label = @Translation("Entity Test view builder"),
+ *   handlers = {
+ *     "access" = "Drupal\entity_test\EntityTestAccessControlHandler",
+ *     "view_builder" = "Drupal\entity_test\EntityTestViewBuilderOverriddenView",
+ *   },
+ *   base_table = "entity_test",
+ *   render_cache = FALSE,
+ *   entity_keys = {
+ *     "id" = "id",
+ *     "label" = "name",
+ *     "bundle" = "type"
+ *   }
+ * )
+ */
+class EntityTestViewBuilder extends EntityTest {
+
+}

core/modules/system/tests/modules/entity_test/src/EntityTestViewBuilderOverriddenView.php

+<?php
+
+/**
+ * @file
+ * Contains \Drupal\entity_test\EntityTestViewBuilderOverriddenView.
+ */
+
+namespace Drupal\entity_test;
+
+use Drupal\Component\Utility\SafeMarkup;
+use Drupal\Core\Entity\EntityInterface;
+
+/**
+ * Provides a view builder that overrides ::view() and ::viewMultiple().
+ */
+class EntityTestViewBuilderOverriddenView extends EntityTestViewBuilder {
+
+  /**
+   * {@inheritdoc}
+   */
+  public function view(EntityInterface $entity, $view_mode = 'full', $langcode = NULL) {
+    $build = [];
+    $build[$entity->id()]['#markup'] = SafeMarkup::checkPlain($entity->label());
+    return $build;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function viewMultiple(array $entities = [], $view_mode = 'full', $langcode = NULL) {
+    $build = [];
+    foreach ($entities as $key => $entity) {
+      $build[$key] = $this->view($entity, $view_mode, $langcode);
+    }
+    return $build;
+  }
+
+}