Wrong room list ordering after edit

[stefanceriu]

We noticed the room list order break after an edit has been sent in one of the rooms. Notice how the 19:12 room is above everything else in the screenshot below.

The room in question is !TAoweeYCttBnjuMqRg:matrix.org, the original 19:12 event is $c-4G24WDEkdbJYcvO7VDAeMDsdYUS-rntkUIzEjVeak and the subsequent 22:19 edit event is $3cEeTTSRQFcuk8NZBUngz1t4mAbca0boetGQBtQU9aE.
There doesn't seem to be anything out of the ordinary about the edit event apart from the time passed in between.

{
  "content": {
    "body": " * [Redacted content..]",
    "m.mentions": {},
    "m.new_content": {
      "body": "[Redacted content..]",
      "format": "org.matrix.custom.html",
      "formatted_body": "[Redacted content..]",
      "m.mentions": {},
      "msgtype": "m.text"
    },
    "m.relates_to": {
      "event_id": "$c-4G24WDEkdbJYcvO7VDAeMDsdYUS-rntkUIzEjVeak",
      "rel_type": "m.replace"
    },
    "msgtype": "m.text"
  },
  "event_id": "$3cEeTTSRQFcuk8NZBUngz1t4mAbca0boetGQBtQU9aE",
  "origin_server_ts": 1734034787585,
  "room_id": "!TAoweeYCttBnjuMqRg:matrix.org",
  "sender": "@redacted:element.io",
  "type": "m.room.message",
  "unsigned": {}
}

[Hywan]

The room is encrypted, so the server cannot filter which events trigger a bump. This is the code that handles that:

matrix-rust-sdk/crates/matrix-sdk-base/src/sliding_sync/mod.rs

Lines 878 to 894 in 150d9e4

	if let Some(recency_stamp) = &room_data.bump_stamp {
	let recency_stamp: u64 = (*recency_stamp).into();
	if room_info.recency_stamp.as_ref() != Some(&recency_stamp) {
	room_info.update_recency_stamp(recency_stamp);
	// If it's not a new room, let's emit a `RECENCY_STAMP` update.
	// For a new room, the room will appear as new, so we don't care about this
	// update.
	if !is_new_room {
	room_info_notable_updates
	.entry(room_id.to_owned())
	.or_default()
	.insert(RoomInfoNotableUpdateReasons::RECENCY_STAMP);
	}
	}
	}

We notice that there is no event filtering whatsoever. We should probably decide which events are candidates to update the recency_stamp.

[pixlwave]

Duplicate of #4062

[stefanceriu]

This must also be why latest messages are sometimes wrong in rooms when rooms when getting decryption keys late / not sharing keys with the NSE(?): the backend bumps them to the top but the app can't yet render the right message.