Deleting users unsets the author of Content

src/Controller/Backend/UserEditController.php

@@ -98,6 +98,12 @@ class UserEditController extends TwigAwareController implements BackendZone
         #$this->validateCsrf($request, 'useredit');
 
         $this->em->remove($user);
+        $contentArray = $this->getDoctrine()->getManager()->getRepository('Bolt\Entity\Content')->findBy(['author' => $user]);
+        foreach($contentArray as $content){
+            $content->setAuthor(null);
+            $this->em->persist($content);
+        }
+
         $this->em->flush();
 
         $url = $this->urlGenerator->generate('bolt_users');

src/Entity/Content.php

@@ -233,7 +233,7 @@ class Content
         return $this->getDefinition()->get('icon_one') ?: $this->getDefinition()->get('icon_many');
     }
 
-    public function getAuthor(): User
+    public function getAuthor(): ?User
     {
         return $this->author;
     }
@@ -447,9 +447,11 @@ class Content
     /**
      * @Groups("get_content")
      */
-    public function getAuthorName(): string
+    public function getAuthorName(): ?string
     {
-        return $this->getAuthor()->getDisplayName();
+        if(!$this->getAuthor() == null)
+            return $this->getAuthor()->getDisplayName();
+        return null;
     }
 
     public function getStatuses(): array

templates/content/_fields_aside.html.twig

@@ -27,7 +27,7 @@
     {% include '@bolt/_partials/fields/text.html.twig' with {
         'label' : 'field.author'|trans,
         'name' : 'author',
-        'value' : record.author.displayName,
+        'value' : record.author.displayName|default('undefined'),
         'disabled' : true
     } %}