The S2S spec says:
Upon receipt of an
Add
activity into the inbox, the server SHOULD add theobject
to the collection specified in thetarget
property, unless:
- the
target
is not owned by the receiving server, and thus they can’t update it.- the
object
is not allowed to be added to thetarget
collection for some other reason, at the receiver’s discretion.
OK, this is straightforward.
But what are the semantics of that: The vocabulary states:
Indicates that the
actor
has added theobject
to thetarget
.
So, the actor in control here is at the sending server, and they want to add something to a collection (the target
). The ActivityPub now says that they can do that for collections under the control of the receiving server, so an actor on server A controls addition of an object to a collection owned by server B here.
To me, that makes no sense – server A should only inform me of additions of objects to collections owned by server A itself., or not?
Of course, that qualifies as “not allowed for some other reason”, but I still wonder what the intention of the spec with the first bullet point is.