Private rooms in Spaces are displayed as Unknown rooms

[EntityinArray]

Describe the bug

CInny shows Private rooms in Spaces as Unknown rooms that you cannot join

Reproduction

1. Go to a Space (for example: https://matrix.to/#/#rossmannrepair:matrix.org)
2. Notice Unknown private rooms

Expected behavior

Private rooms are not displayed

Platform and versions

1. OS Windows 10
2. Browser Chrome 127.0.6533.119
3. Cinny v4.1.0
4. Matrix homeserver isekai.su

Additional context

No response

[SiwonP]

I experienced the same bug but also for not private rooms I have not yet joined.
I looked into the HTTP request and found out that requests

GET /_matrix/client/v1/rooms/{roomId}/hierarchy 

when roomId is the actual of the room return a 403 M_UNAUTHORIZED.

Compared to Element, I see the name and thumbnail of the unjoined rooms.

Hence, I tried to call

GET /_matrix/client/v1/rooms/{roomId}/hierarchy 

Where roomId is the id of the space, and it worked : I got the list of rooms with their names and thumbnails and so on.

I wonder if calling the hierarchy for each room is the way to go.

Anyway, I would gladly volunteer to discuss and implement a patch for this !

Thanks

[williamkray]

indeed, all of this is related to #1846 as well, and discussion with the developers in their matrix room has indicated that this is exactly why it's not working. the spec does not define what that endpoint should return when executed against a non-space room, and conduit apparently returns content properly, which has led the developers to believe that this is a reasonable use of the endpoint despite it not working on synapse, which is probably the most common matrix server implementation in the wild.

the developers have shared that they are working with the synapse team and submitting PRs upstream to attempt to resolve this at the synapse level, which is a significantly slower process and may or may not have success, rather than simply changing their own code's logic to use the appropriate room discovery mechanisms.

[kfiven]

I have repeated this many times but it's a bug in syanpse and instead of building around it we are trying to fix it. Synapse return valid response if room id is local room but if the room is over federation the bug hits. Anyways as this is duplicate of #1846, I am closing it and the progress on it can be tracked on element-hq/synapse#17750