From 9c4bfba01b370151dd3309bb49d6adfdaf99a3bb Mon Sep 17 00:00:00 2001
From: Neil Alexander <neilalexander@users.noreply.github.com>
Date: Mon, 15 Nov 2021 11:56:53 +0000
Subject: [PATCH] Try to match by type/state key tuple rather than event ID

---
 federationsender/internal/perform.go | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/federationsender/internal/perform.go b/federationsender/internal/perform.go
index f358c2ea..cdc80c5c 100644
--- a/federationsender/internal/perform.go
+++ b/federationsender/internal/perform.go
@@ -262,7 +262,10 @@ func (r *FederationSenderInternalAPI) performJoinUsingServer(
 		// Find the membership event.
 		var joinEvent *gomatrixserverlib.Event
 		for _, stateEvent := range respState.StateEvents {
-			if stateEvent.EventID() == event.EventID() {
+			if stateEvent.Type() != gomatrixserverlib.MRoomMember {
+				continue
+			}
+			if stateEvent.StateKeyEquals(*event.StateKey()) {
 				joinEvent = event
 				break
 			}