Merge pull request #13510 from annando/fix-thread-parent

Fix for the display of the thread parent

diff --cc src/Object/Post.php
index c5a4be9d780bcadca093e4ecdcadfbd74566e8fe,9240079fb76f9861c047f31f1a346c3905b1bbd7..4df953cab6b608a4f00e2460f9296d162e0f4c46
--- 1/src/Object/Post.php
--- 2/src/Object/Post.php
+++ b/src/Object/Post.php
@@@ -496,9 -497,12 +497,12 @@@ class Pos
                        $browsershare = null;
                }
  
+               $parent_guid     = $thread_parent[$item['thr-parent-id']]['guid'] ?? '';
+               $parent_username = $thread_parent[$item['thr-parent-id']]['name'] ?? '';
+ 
                $tmp_item = [
                        'parentguid'      => $parent_guid,
 -                      'isreplyto'       => DI::l10n()->t('is reply to %s', $parent_username),
 +                      'isreplyto'       => DI::l10n()->t('in reply to %s', $parent_username),
                        'template'        => $this->getTemplate(),
                        'type'            => implode('', array_slice(explode('/', $item['verb']), -1)),
                        'comment_firstcollapsed' => false,