I have added an image field to my private message entities. When I try to post a Private Message I get the following error.
Error: Cannot initialize readonly property Drupal\private_message\Form\PrivateMessageForm::$typedDataManager from scope Drupal\Core\Form\FormBase in Drupal\Core\Form\FormBase->__wakeup() (line 81 of /.../web/core/lib/Drupal/Core/DependencyInjection/DependencySerializationTrait.php).
This only happens if I upload an image in the newly added field. If I leave the image field empty there is no error and it posts successfully
This is similar to the bug reported in 💬 Error: Cannot initialize readonly property Active . and will post a MR with a similar solution.
Active
4.0
Code