for #2, superblock will do the trick.

1 Yes
2 See @Marshall Sutherland  comment
3 if there is a privacy mismatch Hubzilla will not relay the  comment

Mastodon neither expects nor understands conversations or permissions. Thus, Mastodon neither expects nor understands that Hubzilla posts define the permissions for all replies to them.

Even if a Mastodon replies to a Hubzilla post with the "Followers only" setting, "Followers only" does not mean "only to the followers of the thread starter on Hubzilla". If it's a comment on a comment or a comment on a comment on a comment, chances are Mastodon doesn't even know what the start post is.

It rather means the same it always means when a Mastodon user posts to "Followers only": only to the followers of this particular Mastodon user. And whomever they mention.

Normally, Hubzilla, which closely watches what's happening in a thread, would pick up that reply, forward it to the original poster and add it to the thread for everyone everywhere that understand conversations to pick it up.

But as @Mario Vavti said, this one-sided attempt of a Mastodon user to change permissions within the thread will cause Hubzilla to not forward the reply at all. For if it did forward this reply, the reply would end up in places where the Mastodon user didn't intend it to end up. Within the conversation, only those mentioned in the reply receive it, but it is not forwarded to all those who have the conversation on their stream.

How does Hubzilla behave when a post or comment is published in a private group and then shared by a member of that private group? Does it then behave as Mario described in point 3?

@Markus AFAIK, you don't even have a Share button on a private post.

@Jupiter Rowland I have never paid attention to this myself, hence my somewhat stupid question.

@Jupiter Rowland

Thanks.  This also clarifies to me at least one context in which broken threads can occur on Hubzilla.

@dynamic_hubzilla Which context is that?

@Marshall Sutherland @dynamic_hubzilla Superblock helps #2 but is buggy. For instance you will receive notifications, when contacts of you share a post by a blocked user. These notifications can't be clicked, and they only go away, when you click "mark all notifications read"

@_jayrope

As Jupiter indicated, broken threads on Hubzilla occur when a Mastodon post is boosted onto Hubzilla after Mastodon replies have been posted.  If he's correct, then only Mastodon replies made after the boost will show up in the Hubzilla conversation, meaning that we'll only get to see a fragmented version of the conversation on this end.

@_jayrope It has been years since I superblocked anyone, so there could very well be problems I either don't remember or never experienced.

@dynamic_hubzilla What I actually meant is that comments from Mastodon are missing from threads on Hubzilla if the Mastodon user has screwed with the permissions, and the permissions of the Mastodon comment clash with those of the start post which define the permissions in the whole thread. In this case, Hubzilla does accept the comment, but it refuses to forward the comment to those whom it'd normally forward the comment to because it deems the comment unsecure.

@Marshall Sutherland My list is long. If i could only just mute people i don't have in my connections instead.

I wonder what it would take to make the reverse of superblock where the list is your current connections.

@Marshall Sutherland Like a reverse block list. An allow list.

Another option is a change to the UI, where certain comments are collapsed based on certain criteria. For example, if you only want to see posts and comments from your connections (using that as an allow list), when people comment on threads but aren't on your contact list, their post is collapsed. You can see who it is from and decide to uncollapse it or not.

This is similar to how some platforms collapse downvoted posts rather than hide them completely.

@Jupiter Rowland

Which I think is another way of saying that if I post a "Friends only" post, and Mastodon replies are automatically configured as "Followers only", which seems like what Mastodon would do, then my Hubzilla "Friends" would not be able to see the Mastodon posts, even if they come from Mastodon people that they follow, i.e. a broken thread in that they can't have conversations with each other even though all participants would want for it to happen and that it is what I as original poster would intuitivley expect.  

If I got any parts of this chain incorrect, then you're going to need to explain again how this works.  Except in the case of public posts, Mastodon permissions are almost never going to match with Hubzilla permissions, regardless of whether the Mastodon user "has screwed with" the permissions.

@dynamic_hubzilla Mastodon understands anything coming from Hubzilla that isn't public as per ACL as a direct message. In a reply to a DM, Mastodon users can't mess with the privacy settings.

But in general, in each thread that starts on Hubzilla, there are permissions in play. They may not necessarily be restrictive, but they are in play.

Let's play this through.

Alice (on Hubzilla) starts a thread. Permission: public.
Bob (on Hubzilla) replies to Alice without mentioning her.
Carol (on Hubzilla) replies to Alice without mentioning her.

Now comes Dave. Dave is on Mastodon. Dave has caught Bob's comment somehow, and be it by following a hashtag that Bob has inserted or by being one of the few Mastodon users who can be bothered to open up a whole thread instead of only looking at that one post.

At this point, it's important to know that Dave knows nothing about Hubzilla. If you're lucky, he has heard the name. Probably not even that. He doesn't know anything about Hubzilla's permissions system. And, in fact, he doesn't even notice that neither Alice's post nor Bob's comment didn't come from Mastodon. So he assumes it's all from Mastodon.

Now, Dave wants to reply to Bob's comment on Alice's post.

Normally, Dave's reply would go to Bob, from him to Alice and from Alice to Carol and everyone else on Friendica, Hubzilla, (streams) etc. who has Alice's post in their timeline/stream.

But on the one hand, Dave doesn't know that Alice will receive his reply because she isn't automatically mentioned in his reply, because she wasn't mentioned in Bob's comment. Only Bob is mentioned.

On the other hand, Dave's comment, originating on Mastodon, will just as well directly go to his followers, to the local timeline of his home instance and to the federated timelines of his followers on other instances.

But Dave doesn't want that. He doesn't want his reply to be that public. He only wants it to go to Bob, who is mentioned, plus his own followers without it hitting any public timeline.

Mind you, normally, Dave's reply would go to

• Alice (whom he doesn't mention, and who doesn't follow him)
• Bob (whom he does mention)
• Carol (whom he doesn't mention, who doesn't follow him, and of whom he doesn't know that she has participated in the thread in the first place)
• Alice's contacts on Friendica, Hubzilla and (streams)
• the public timelines/streams of the instances which Alice, Bob, Carol and Alice's contacts are on
• everyone else who follows the thread

Yeah, but Dave wants his reply not to be public.

As per Hubzilla's modus operandi, he doesn't have any saying in where his reply goes and where it doesn't go. But neither Dave nor Mastodon knows anything about Hubzilla's modus operandi.

And so Dave switches his reply to "Followers only". Result: Mastodon's order where Dave's reply shall go contradicts Hubzilla's order where Dave's reply shall go.

Of course, the hub that Bob is on, the only one involved in the thread whom Dave mentions and therefore the only one to whom Dave's reply goes directly, notices this contradiction.

The hub decides that with this discrepancy in permissions (with any discrepancy in permissions, in fact), Dave's reply is too unsafe to handle. Bob receives it. But chances are that the hub already refuses to forward Dave's reply to Alice because it's unsafe. After all, as per the combination of Dave's "Followers only" setting and Mastodon's behaviour, his reply should only go to Bob and Dave's followers and nobody else.

Result: Alice doesn't get Dave's reply, Carol doesn't get Dave's reply, and all those on Friendica, Hubzilla and (streams) who have Alice's post in their timelines/streams don't get Reply either. All of them see incomplete threads. And Bob sees a red padlock on Dave's reply.