Old posts sometimes inserted into the timeline about mastodon

[deanveloper]

Yeah I'm almost certain that's the issue. Glad sidekiq logged it! My bad, I'll take a look to see if there's some Ruby tooling in VSCode that will catch stuff like before it's an issue at runtime since this was introduced by me LOL

[deanveloper]

For the record, this is probably a mastodon/glitch-soc bug but I'm not sure

[neatchee]

I think this is intended design: The federated feed displays anything that is interacted with by users on our instance, right? If one of our users favorites a day old post, that post will show up in the federated feed shortly thereafter despite being a day old.

There might also be some access pattern stuff going on here? I'm not familiar enough with the internals, but I know there is a comprehensive retry system in place, so this could theoretically be a consequence of a very stale request finally going through to another server.

[deanveloper]

https://urusai.social/@[email protected]/109603022970728801

This 2 day old post appears to be entirely unprompted - no favorites nor boosts (within our federation). I think you might be right with the stale request. It just seems weird how often this occurs, and it's almost always with this exact account. Granted I don't know if I follow any other accounts from botsin.space.

Possible solutions could be either to implement this on the frontend by sorting the post into the correct spot, or on the backend by doing a quick "recency" check (ie, only posts/boosts from the last 5 minutes will be sent over pubsub/websockets)

[neatchee]

So, keep in mind, we federate with a relay. Relay-provided posts won't show follows unless you click all the way through to their instance (and they have it visible).

And this probably goes back to my security concern re: young accounts - I could imagine that the bot account owner also set up follower accounts on big instances that automatically like/boost posts from the bot account after N hours

[neatchee]

Nevermind, there's definitely something up. I'm rolling back the public boost feature too see if that resolves it as only posts within the past 3 days are showing this behavior

[neatchee]

Ok, so before reverting Sidekiq was showing a ton of retry entries with a "missing argument" error related to "silenced_account_ids". I think this is the culprit line:

mastodon/app/services/fan_out_on_write_service.rb

Line 135 in a2e5044

redis.publish("#{channel}:media")

Note that in the function immediately preceding that line we have a second argument in the publish function for "anonymous_payload"

I'm like 99% sure that's it as that payload contains the rendered_status variable which I would assume is how the timeline filters out things like old posts from appearing a second time on the home timeline due to new boosts/etc and how post publishing works.

Testing that as a fix now.

[neatchee]

Upside, that may be (at least part of) the feature(s) we need to pipe through to the local/federated timelines to help with suppressing duplicate boosts when that's enabled :D