History in a recently created room is silently hidden from new members

joepie91 commented 3 years ago

Description

Joining as a new user in a room with private room history, gives no indication that this is the case; the room just looks empty and dead.

From the perspective of someone already in the room:

Selection_366

And then from the perspective of a new user:

Selection_367

Steps to reproduce

Create a room that has history set to "members only from when they joined"
Say something in the room
Join from another user
See an empty room, no history, nor any indication that history was elided

This should include a clear indicator that the room history is being hidden, so that the user understands that there may have been conversational history (and the room isn't dead), they just can't see it. Similar to how there's a clear "this room uses E2EE" indicator after joining it, really.

In fact, I'd argue that the "this is the start of the room" without an elided-history marker is actively misleading to users, as it almost explicitly says that there isn't something being elided!

Logs being sent: no

Version information

Platform: web/desktop, specific versions not relevant - it's just a missing feature

robintown commented 3 years ago

So I would like to solve this in matrix-org/matrix-react-sdk#5887, but I'm not even sure API-wise how to detect there being hidden history in this case, since the homeserver silently returns the room creation event as if that's all there is. Could someone with more knowledge of the spec please explain why the room creation events are even given to the client in this case? (Shouldn't they be hidden as well?)

robintown commented 3 years ago

Hmm, I just tried reproducing this with Dendrite instead of Synapse and I couldn't. Instead, Dendrite seems to be hiding the room creation events as I hoped it would, leading me to believe that the specific scenario you're seeing above is a Synapse bug.

As for showing a message when history is hidden, that will be resolved by matrix-org/matrix-react-sdk#5887.

robintown commented 3 years ago

Opened matrix-org/synapse#9923