Message Editing: Block attempts to edit other people's edits via /_matrix/client/v3/rooms/{roomId}/send

[jryans]

I can't quite recall where we left this, so filing an issue to track...

It looks like Synapse currently ignores edits from other senders (those who did not send the original message) when constructing the data to bundled into original event. However edits from others currently still come through on the timeline.

We should block edits from other senders in the timeline as well (or even at send time if possible)

[Half-Shot]

If we want to enforce this, it should probably be a spec item. Last time this came up though, I remember a lot of people had use cases for editing other's messages (multiple admins editing a pinned message came to mind).

[jryans]

I have added a comment about this on the aggregations MSC.

[chagai95]

(multiple admins editing a pinned message came to mind).

This is a great use case, there is a precedent for this on telegram channels, I used it and would love to see this possible on matrix 🙃

[thebiblelover7]

Is this going to be possible anytime soon? I would really like to have this as a kind of "telegram channel" functionality like @ chagai95 said.

[richvdh]

We should block edits from other senders in the timeline as well (or even at send time if possible)

I don't particularly agree that homeservers should be responsible for blocking malformed edits, for the reasons set out in MSC2801.

We could certainly block attempts to send such edits via the C-S API, though I don't think it will be much use (given we can't block such events over federation).