I can post to !cashless_society@nano.garden, no problem. But then when visiting nano.garden there is no Lemmy server there.
What I think is going on: nano.garden was once a Lemmy server that federated to Sopuli, Sopuli users subscribed, and then nano.garden ghosted us… disappeared. Yet posts can still be composed and old posts are still viewable locally. Participants carry on with the illusion that nano.garden exists.
Amiright? What are the consequences? Does this mean Sopuli users can only see new posts that come from other Sopuli users going forward?
I think this is the same issue that comes up when servers de-federate. A ghost version of the remote community remains available to the local server even though the posts, comments, and votes are never federated. It’s a hard problem, you want servers to be able to recover federation easily from temporary disconnects and there’s no good way to tell the difference between a temporary and permanent disconnection or de-federation.
It seems a simple fix would be for the side-bar to show a timestamp of the last sync operation with the originating node.
(edit) well, fix for the transparency problem. There is still possibly the problem that posts from node A and node B cannot intermingle, IIUC.
That’s a really good idea, you could even add a warning when someone tries to post or comment after some length of time.