If the HS doesn't think there are any users in a room, perhaps it should have the (default) option of automatically deleting any aliases that refer to it (SYN-7)

[matrixbot]

(Imported from https://matrix.org/jira/browse/SYN-7)

(Reported by @ara4n)

[matrixbot]

Jira watchers: @ara4n

[ShadowJonathan]

Is this specific to a HS having no users from itself in a room, or when a HS receives the last leave event?

I think that there are usecases for leaving empty rooms with aliases around, e.g. some automated client could join a room, dump some data, and then leave, and then do this with thousands of likewise rooms. Or someone can simply make a mistake of leaving their own room (getting automatic admin permission is discussed in https://github.com/matrix-org/matrix-doc/issues/652), to then be able to rejoin it again. Other reasons could be one of privacy/obscurity, to hide a room inside an alias on a homeserver, to leave it, and only come back when required.

[MadLittleMods]

This is probably more important to a large shared homeserver like matrix.org where people create rooms which die and the alias is forever locked up.

Perhaps this is better addressed by a dormant alias policy and some release request system to reclaim aliases.

Generally like @ShadowJonathan mentioned, this doesn't seem that applicable to everything. I was even tempted to close this out until I thought of the matrix.org use case.

[ShadowJonathan]

Yeah, i think that this is mainly an admin question, maybe this should be implementable/doable through the module interface?

[richvdh]

this isn't immediately about the room directory: the first problem is to remove the alias, which should in turn update the room directory (though see also #6346).

[richvdh]

Fixing this might also help with the situation where a /join fails because you're attempting to join a room through a server that is no longer in the room.