Issue #3161212 by joseph.olstad, acbramley, asubit, eduardo morales alberti, sandeepsingh199, berdir, catch: Node add/edit gives a Call to a member function getAccountName() on null when author is NULL

(cherry picked from commit ca57f2128a)

core/modules/node/src/NodeForm.php

@@ -163,7 +163,7 @@ class NodeForm extends ContentEntityForm {
     $form['meta']['author'] = [
       '#type' => 'item',
       '#title' => $this->t('Author'),
-      '#markup' => $node->getOwner()->getAccountName(),
+      '#markup' => $node->getOwner()?->getAccountName(),
       '#wrapper_attributes' => ['class' => ['entity-meta__author']],
     ];
 

core/modules/node/tests/modules/node_no_default_author/node_no_default_author.info.yml

@@ -0,0 +1,5 @@
+name: 'Node no default author'
+type: module
+description: 'Disables the default value callback for the uid field on node.'
+package: Testing
+version: VERSION

core/modules/node/tests/modules/node_no_default_author/src/Hook/NodeNoDefaultAuthorHooks.php

@@ -0,0 +1,31 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Drupal\node_no_default_author\Hook;
+
+use Drupal\Core\Entity\EntityTypeInterface;
+use Drupal\Core\Hook\Attribute\Hook;
+
+/**
+ * Hook implementations for node_no_default_author.
+ */
+class NodeNoDefaultAuthorHooks {
+
+  /**
+   * Implements hook_entity_base_field_info_alter().
+   */
+  #[Hook('entity_base_field_info_alter')]
+  public function entityBaseFieldInfoAlter(&$fields, EntityTypeInterface $entity_type): void {
+    if ($entity_type->id() === 'node') {
+      $fields['uid']->setDefaultValueCallback(static::class . '::noDefaultAuthor');
+    }
+  }
+
+  /**
+   * An empty callback to set for the default value callback of uid.
+   */
+  public static function noDefaultAuthor(): void {
+  }
+
+}

core/modules/node/tests/src/Functional/NodeEditFormTest.php

@@ -258,6 +258,16 @@ class NodeEditFormTest extends NodeTestBase {
     $this->assertSession()->pageTextContains($this->container->get('date.formatter')->format($node->getChangedTime(), 'short'));
   }
 
+  /**
+   * Tests the node form when the author is NULL.
+   */
+  public function testNodeFormNullAuthor(): void {
+    \Drupal::service('module_installer')->install(['node_no_default_author']);
+    $this->drupalLogin($this->adminUser);
+    $this->drupalGet('node/add/page');
+    $this->assertSession()->statusCodeEquals(200);
+  }
+
   /**
    * Checks that the "authored by" works correctly with various values.
    *