Related to the ForumWG topic of resolvable context collections, there are four FEPs that are currently in consideration:

  1. FEP-7888: Demystifying the context property
  2. FEP-400e: Publicly-appendable ActivityPub collections
  3. Draft FEP-171b: Conversation Containers, an evolution of Conversation Containers
  4. FEP-76ea: Conversation Threads

@[email protected] made a suggestion last month to hopefully reduce the number of moving parts:

  • Both FEP-400e and FEP-1b12 implementations: support FEP-7888 (context collection)
  • FEP-400e implementations: upgrade to Conversation Containers
  • FEP-1b12 implementations: add target property to Announce activity that points to context collection.

This takes FEP 400e out of the running (potentially). But the day after that last meeting, @[email protected] put together FEP 76ea, and now we’re back to three.

My concern is that all three FEPs (7888, 171b, and 76ea) all share these distinct qualities:

  • They establish a conversational context for a given object
  • They federate out an Add on collection addition. (76ea also sends Remove)
  • They contain some concept of a context owner (attributedTo)

They differ on the following qualities:

  • 7888/171b use context whereas 76ea uses a new property thr:thread
  • 171b specifies a new object type Context
  • Collection items:
    • 7888 sends objects in chronological order
    • 171b sends activities in chronological order
    • 76ea sends objects in reverse chronological order

In the lead up to the November WG meeting I’d like to address those differences. All three FEPs are in pre-draft or draft stages, and so I am hoping we can find some common ground and compromise.


Pinging interested parties (who were not already mentioned above) for comment:

@[email protected] @[email protected] @[email protected] @[email protected]

  • Mike Macgirvin 🖥️@fediversity.site
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    20 days ago

    Conversation containers does send a ‘Remove’ if something is removed from a collection. But we typically don’t waste resources on spammers, so we don’t necessarily send a ‘Remove’ if we decided not to add it in the first place (perhaps due to comment controls, permissions, or blocks). You can send these as Remove activities if you want, but please don’t force me to do so.

    If you’ve fetched a conversation collection, it would be most common to do so in order to cache the conversation locally. In this case storing under local entities is going to be much more efficient if parents are stored before their children, so the InReplyTo can be pointed to an existing stored entity. If you do it backward, it’s kind of awkward.

    That said, our implementation of Collection objects has a flag to reverse the returned item order. So as long as the order is defined and isn’t going to change, I don’t actually care what it is; beyond the storage efficiency mentioned above. We need to sort it how we want after fetch anyway, because that’s just basic input sanitisation.

    It would seem most natural to me to send the collection in “thread” order - start from the root and recursively traverse every branch/leaf encountered. I’ll mention this for consideration – but again I really don’t care.