Trying to send a message to myself displays an error on screen:
TypeError: Drupal\Core\Field\Plugin\Field\FieldWidget\EntityReferenceAutocompleteWidget::massageFormValues(): Argument #1 ($values) must be of type array, null given, called in /home/ce-dev/deploy/live.local/web/core/lib/Drupal/Core/Field/WidgetBase.php on line 505 in Drupal\Core\Field\Plugin\Field\FieldWidget\EntityReferenceAutocompleteWidget->massageFormValues() (line 149 of core/lib/Drupal/Core/Field/Plugin/Field/FieldWidget/EntityReferenceAutocompleteWidget.php).
Problem is located here:
open_social/modules/social_features/social_private_message/src/Element/SocialPrivateMessageEntityAutocomplete.php
After:
parent::validateEntityAutocomplete($element, $form_state, $complete_form);
$value = $form_state->getValue('members');
$form_state->setValue('members', $value['target_id']);
It assume $value['target_id'] will have always a valid id, but the parent call can return NULL.
Needs review
12.4
Private messages