Enable the Contact module and the POST /entity/contact_message REST endpoint. You can successfully create a contact message, however, the email will not be sent.
This is because the logic to send the message is in \Drupal\contact\MessageForm::save(). Since the logic is tied to the form, instead of the entity. The message should be sent when the entity is "saved".
Move the message sending logic to the entity instead of the form.
None
Creating a new contact_message will send the email(s) just like the UI does.
None.
Needs work
11.0 🔥
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It's likely this issue predates Contrib.social: some issue and comment data are missing.
Rerolled #44 for 11.x, converted to MR, hiding patches.