Element not allowing Invitation rejection - Maybe a 2XX response is needed when a room no longer exists?

[yaliqmadiq]

Background information

• Dendrite version or git SHA: e08942f
• Monolith or Polylith?: mono
• SQLite3 or Postgres?: postgres
• Running in Docker?: no
• go version: 1.16.3

Description

When a user (like a troll) sends invites and then deletes the room, it's not possible to reject the invite in Element or even accept and then leave the room because Dendrite is not sending a positive HTTP code, which confuses Element.

Steps to reproduce

• User creates a room
• Send invite
• Leave room before invitation is answered

https://user-images.githubusercontent.com/82163887/114427213-de28b780-9b88-11eb-8f03-334964e433b7.mp4

I apologize for the language in this capture, but this is what a troll did on our instance. I have to go into the database to hunt down and whack this pending invitation manually.

[yaliqmadiq]

Invite is going to an invalid NID, I can clear the invites table of these manually.