My replies via Mastodon to Lemmy posts don’t get distributed as expected. For example:

It seems my reply only shows in these Lemmy servers:

  • lemmy.ml (the server of the group to which the post was made)
  • lemmy.world (the server of the post’s author)
  • ttrpg.network (the server of the comment’s author)

From some other lemmy servers, my comment is not present:

I expected that my reply would show on any other Lemmy server with subscriptions to [email protected]. Does that make sense? I’m hoping to help troubleshoot federation like this as I’m super excited about ActivityPub and what it means for the internet! :)

    • Oliver LoweOPEnglish
      6•5 months ago

      Good question! Sorry if this answer is weird :)

      For me, I don’t actually interact from Mastodon per se. I wrote a couple of read-only Lemmy & Mastodon clients. One for a weird text editing environment I use (https://lemmy.sdf.org/post/1035382) and via email (https://gts.olowe.co/@o/statuses/01HMQ9N4HQ2ETGZWJS49K5NG5Y). To reply to or create posts, I use a write-only Mastodon client I wrote.

      My idea is to exercise the fediverse. In principal I don’t think I should need separate accounts for Lemmy, PeerTube, Mastodon, Kbin, Akkoma, etc.

      Right now I’m replying from an account on lemmy.sdf.org as I can’t reply from GoToSocial (Lemmy and GoToSocial don’t work well together right now) and my Mastodon server (hachyderm.io) has a post limit of 500 characters.

        • @[email protected]English
          1•4 months ago

          Hey, bit late to this discussion (found it while searching for something) but since you seemed interested in a casual user’s pov:

          I’m a member of quite a few Lemmy communities that are really small, and I’m very active on Mastodon. So having those small communities in a list feed on Mastodon is really handy since I don’t miss anything and can just jump in with a reply on stuff without switching over to Lemmy.

          I also post a lot of the same type of stuff to both platforms and sometimes it makes sense to keep that separate, but sometimes with niche interests it’s nice to be able to cross-post and get both groups of people chatting together in the comments.

          Of course this is a moot point because federation between my Masto instance and Lemmy is currently broken, but it was really great before and I miss it a ton.

  • Rimu
    6•5 months ago

    While both Lemmy and Mastodon use ActivityPub, the way they send ActivityPub messages to each other differs quite a bit. There is not a simple or quick solution to this. However recently I read about Lemmy having improved integration with https://a.gup.pe/, a service that adds Groups support to Mastodon so that might be something you want to try out.

    Mastodon having so many users makes it a tempting target for integration but federation with software that uses Groups properly (e.g. PeerTube, Friendica) is likely to be easier to achieve.

    • Oliver LoweOPEnglish
      2•5 months ago

      Gotcha. I had a feeling something around how Mastodon doesn’t support ActivityPub Groups (yet?) would be where things are going on. Congrats on piefed, by the way. I’ll start studying the codebase now as I’m keen to understand how server-to-server communication works more deeply than I do now. Sending Announce(?) and fetching stuff from other servers…

      When I look at the ActivityPub Note object (via curl -H 'Accept: application/activity+json https://hachyderm.io/@otl/111887721960075860) I see:

      {
    "@context": [
        "https://www.w3.org/ns/activitystreams",
        {
            "ostatus": "http://ostatus.org#",
            "atomUri": "ostatus:atomUri",
            "inReplyToAtomUri": "ostatus:inReplyToAtomUri",
            "conversation": "ostatus:conversation",
            "sensitive": "as:sensitive",
            "toot": "http://joinmastodon.org/ns#",
            "votersCount": "toot:votersCount"
        }
    ],
    "id": "https://hachyderm.io/users/otl/statuses/111887721960075860",
    "type": "Note",
    "summary": null,
    "inReplyTo": "https://ttrpg.network/comment/4965852",
    "published": "2024-02-07T01:59:08Z",
    "url": "https://hachyderm.io/@otl/111887721960075860",
    "attributedTo": "https://hachyderm.io/users/otl",
    "to": [
        "https://www.w3.org/ns/activitystreams#Public"
    ],
    "cc": [
        "https://hachyderm.io/users/otl/followers",
        "https://ttrpg.network/u/Neato",
        "https://lemmy.world/u/ForgottenFlux"
    ],
    "sensitive": false,
    "atomUri": "https://hachyderm.io/users/otl/statuses/111887721960075860",
    "inReplyToAtomUri": "https://ttrpg.network/comment/4965852",
    "conversation": "tag:hachyderm.io,2024-02-06:objectId=123754186:objectType=Conversation",
    "content": "<p><span>@<span>Neato</span></span> <span>@<span>ForgottenFlux</span></span>  I totally get how you feel. One use-case I think of is machine-generated image alt-text. These are often not added to images. But with image-to-text ML models, visually-impaired people could hear a descriptions of images that before were never annotated.</p>",
    "contentMap": {
        "en": "<p><span>@<span>Neato</span></span> <span>@<span>ForgottenFlux</span></span>  I totally get how you feel. One use-case I think of is machine-generated image alt-text. These are often not added to images. But with image-to-text ML models, visually-impaired people could hear a descriptions of images that before were never annotated.</p>"
    },
    "attachment": [],
    "tag": [
        {
            "type": "Mention",
            "href": "https://ttrpg.network/u/Neato",
            "name": "@[email protected]"
        },
        {
            "type": "Mention",
            "href": "https://lemmy.world/u/ForgottenFlux",
            "name": "@[email protected]"
        }
    ],
    "replies": {
        "id": "https://hachyderm.io/users/otl/statuses/111887721960075860/replies",
        "type": "Collection",
        "first": {
            "type": "CollectionPage",
            "next": "https://hachyderm.io/users/otl/statuses/111887721960075860/replies?only_other_accounts=true&amp;page=true",
            "partOf": "https://hachyderm.io/users/otl/statuses/111887721960075860/replies",
            "items": []
        }
    }
}

      So I’m assuming an Announce was posted to the shared inboxes at lemmy.ml, lemmy.world and ttrpg.network… hmm… I better start reading!

  • T JediEnglish
    4•5 months ago

    One way to ensure your comment to federate the way you are expecting is to mention the original group (community) of the thread. This way, Lemmy will receive the comment on the group’s inbox and propagate to all federated servers.

    Another behavior I found is that replies to non federated comments (as the one you showed in the op) will be announced to all federated servers. More details I found here: https://seb.jambor.dev/posts/understanding-activitypub-part-2-lemmy/

    • Oliver LoweOPEnglish
      4•5 months ago

      Ah ha makes sense now! The “Replying to comments” section of that article explains exactly what’s happening. If I understand correctly the community itself ([email protected] in my above example) is not notified of my reply from Mastodon. If the community did know, then it would broadcast a notification of the activity to whoever else is subscribed to [email protected].

  • mozz
    1•5 months ago

    Federation in general seems like it’s been flaky as hell ever since a month or two ago… my guess (especially if you see it on some Lemmy servers and not others) is that it’s delayed and will show up eventually.

    It’s possible that there’s some unexpected behavior that leads it to federate some places and not others, but my expectation is that once your comment is on lemmy.ml’s server, it’s federation delay between the Lemmy servers and nothing to do with you specifically.

  • @canEnglish
    1•5 months ago

    I think the instances would already need to be federated?