Question: What does Lemmy do with comments to a posting where the posting federation is delayed?
What if serverB is down while serverA has a user on it that creates a new posting in a federated community. serverA is in a queue retry state of sending the posting to serverB. But what if the serverB comes online and a new comment is added on serverA before serverB ever received the posting (which is still in a delivery queue waiting for retry).
Events in numbered sequence:
- serverB goes offline. It was subscribed to serverA community.
- user on serverA creates a new post "I like the new version of Lemmy".
- serverA fails to connect to serverB in outbound federation queue, goes into sleep state between retries to serverB.
- serverB is now back online.
- user on serverA creates a new comment.
- serverA connects to serverB in outbound federation to deliver comment.
But at this point, serverB is receiving a comment that it does not have a posting for. Does it accept it, and put it in the PostgreSQL database, or reject the federation?