From 5a7d36d1b3166632763c34fac35bf55c2c3d8353 Mon Sep 17 00:00:00 2001
From: Till Faelligen <2353100+S7evinK@users.noreply.github.com>
Date: Wed, 12 Jul 2023 14:48:44 +0200
Subject: [PATCH] Only leave/kick if the redacted event is the current state
 event

---
 roomserver/internal/input/input_events.go | 16 ++++++++++++----
 1 file changed, 12 insertions(+), 4 deletions(-)

diff --git a/roomserver/internal/input/input_events.go b/roomserver/internal/input/input_events.go
index 81e2e2b9d..db3cd1986 100644
--- a/roomserver/internal/input/input_events.go
+++ b/roomserver/internal/input/input_events.go
@@ -526,8 +526,19 @@ func (r *Inputer) processRoomEvent(
 // leavePseudoIDRoom leaves/kicks a user in the event of a membership event redaction.
 // TODO: This doesn't play well with users re-joining rooms, as in this case we have multiple join events with a mxid_mapping.
 func (r *Inputer) leavePseudoIDRoom(ctx context.Context, roomID spec.RoomID, originalRedactedEvent, redactionEvent gomatrixserverlib.PDU) error {
+
+	stateKey := originalRedactedEvent.StateKey()
+	currentStateEvent, err := r.DB.GetStateEvent(ctx, roomID.String(), originalRedactedEvent.Type(), *stateKey)
+	if err != nil {
+		return err
+	}
+	// If the redacted event is NOT the current state event, do nothing
+	if currentStateEvent.EventID() != originalRedactedEvent.EventID() {
+		return nil
+	}
+
 	var memberContent gomatrixserverlib.MemberContent
-	if err := json.Unmarshal(originalRedactedEvent.Content(), &memberContent); err != nil {
+	if err = json.Unmarshal(originalRedactedEvent.Content(), &memberContent); err != nil {
 		return err
 	}
 	if memberContent.Membership != spec.Join {
@@ -549,9 +560,6 @@ func (r *Inputer) leavePseudoIDRoom(ctx context.Context, roomID spec.RoomID, ori
 		return nil
 	}
 
-	// check that the redacted event is the _current_ membership event
-	stateKey := originalRedactedEvent.StateKey()
-
 	signingIdentity, err := r.SigningIdentity(ctx, roomID, *userID)
 	if err != nil {
 		return err