Issue #3033686 by tedbow, tim.plunkett: Saving Layout override will revert...

Issue #3033686 by tedbow, tim.plunkett: Saving Layout override will revert other field values to their values when the Layout was started

core/modules/layout_builder/src/Form/OverridesEntityForm.php

@@ -114,9 +114,28 @@ public function buildForm(array $form, FormStateInterface $form_state, SectionSt
    * {@inheritdoc}
    */
   public function buildEntity(array $form, FormStateInterface $form_state) {
+    /** @var \Drupal\Core\Entity\FieldableEntityInterface $section_storage_entity */
+    $section_storage_entity = $this->sectionStorage->getContextValue('entity');
+
+    // @todo Replace with new API in
+    //   https://www.drupal.org/project/drupal/issues/2942907.
+    /** @var \Drupal\Core\Entity\FieldableEntityInterface $active_entity */
+    $active_entity = $this->entityTypeManager->getStorage($section_storage_entity->getEntityTypeId())->load($section_storage_entity->id());
+
+    // Any fields that are not editable on this form should be updated with the
+    // value from the active entity for editing. This avoids overwriting fields
+    // that have been updated since the entity was stored in the section
+    // storage.
+    $edited_field_names = $this->getEditedFieldNames($form_state);
+    foreach ($section_storage_entity->getFieldDefinitions() as $field_name => $field_definition) {
+      if (!in_array($field_name, $edited_field_names) && !$field_definition->isReadOnly() && !$field_definition->isComputed()) {
+        $section_storage_entity->{$field_name} = $active_entity->{$field_name};
+      }
+    }
+
     // \Drupal\Core\Entity\EntityForm::buildEntity() clones the entity object.
     // Keep it in sync with the one used by the section storage.
-    $this->setEntity($this->sectionStorage->getContextValue('entity'));
+    $this->setEntity($section_storage_entity);
     $entity = parent::buildEntity($form, $form_state);
     $this->sectionStorage->setContextValue('entity', $entity);
     return $entity;

core/modules/layout_builder/tests/src/Functional/LayoutBuilderTest.php

@@ -106,6 +106,53 @@ public function testOverrides() {
     $assert_session->pageTextNotContains('This is an override');
   }
 
+  /**
+   * Tests that the Layout Builder preserves entity values.
+   */
+  public function testPreserverEntityValues() {
+    $assert_session = $this->assertSession();
+    $page = $this->getSession()->getPage();
+
+    $this->drupalLogin($this->drupalCreateUser([
+      'configure any layout',
+      'administer node display',
+    ]));
+
+    // From the manage display page, go to manage the layout.
+    $this->drupalGet('admin/structure/types/manage/bundle_with_section_field/display/default');
+    $this->drupalPostForm(NULL, ['layout[enabled]' => TRUE], 'Save');
+    $this->drupalPostForm(NULL, ['layout[allow_custom]' => TRUE], 'Save');
+    // @todo This should not be necessary.
+    $this->container->get('entity_field.manager')->clearCachedFieldDefinitions();
+
+    $this->drupalGet('node/1');
+    $assert_session->pageTextContains('The first node body');
+
+    // Create a layout override which will store the current node in the
+    // tempstore.
+    $page->clickLink('Layout');
+    $page->clickLink('Add Block');
+    $page->clickLink('Powered by Drupal');
+    $page->pressButton('Add Block');
+
+    // Update the node to make a change that is not in the tempstore version.
+    $node = Node::load(1);
+    $node->set('body', 'updated body');
+    $node->save();
+
+    $page->clickLink('View');
+    $assert_session->pageTextNotContains('The first node body');
+    $assert_session->pageTextContains('updated body');
+
+    $page->clickLink('Layout');
+    $page->pressButton('Save layout');
+
+    // Ensure that saving the layout does not revert other field values.
+    $assert_session->addressEquals('node/1');
+    $assert_session->pageTextNotContains('The first node body');
+    $assert_session->pageTextContains('updated body');
+  }
+
   /**
    * {@inheritdoc}
    */