From 021f2762558b9a6c87b2da8c5e29554441b4e8fc Mon Sep 17 00:00:00 2001
From: Neil Alexander <neilalexander@users.noreply.github.com>
Date: Fri, 25 Mar 2022 12:16:34 +0000
Subject: [PATCH] Bug fixes

---
 syncapi/streams/stream_pdu.go | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/syncapi/streams/stream_pdu.go b/syncapi/streams/stream_pdu.go
index 5930fb1a1..93e5067dc 100644
--- a/syncapi/streams/stream_pdu.go
+++ b/syncapi/streams/stream_pdu.go
@@ -147,7 +147,6 @@ func (p *PDUStreamProvider) IncrementalSync(
 		To:        to,
 		Backwards: from > to,
 	}
-	newPos = from
 
 	var err error
 	var stateDeltas []types.StateDelta
@@ -168,10 +167,15 @@ func (p *PDUStreamProvider) IncrementalSync(
 		}
 	}
 
+	if len(stateDeltas) == 0 {
+		return to
+	}
+
 	for _, roomID := range joinedRooms {
 		req.Rooms[roomID] = gomatrixserverlib.Join
 	}
 
+	newPos = from
 	for _, delta := range stateDeltas {
 		var pos types.StreamPosition
 		if pos, err = p.addRoomDeltaToResponse(ctx, req.Device, r, delta, &eventFilter, req.Response); err != nil {