From 78d74ea3ee5fd748a215397d02b23fbf06402130 Mon Sep 17 00:00:00 2001
From: Joachim Bauch <bauch@struktur.de>
Date: Thu, 11 Dec 2025 09:58:36 +0100
Subject: [PATCH 1/3] Start timer for anonymous sessions to join room before
 sending response.

Fixes flaky "TestExpectAnonymousJoinRoomAfterLeave" under load.
---
 hub.go | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/hub.go b/hub.go
index a122de9..5a33bde 100644
--- a/hub.go
+++ b/hub.go
@@ -1719,11 +1719,11 @@ func (h *Hub) processRoom(sess Session, message *ClientMessage) {
 	if roomId == "" {
 		// We can handle leaving a room directly.
 		if session.LeaveRoomWithMessage(true, message) != nil {
-			// User was in a room before, so need to notify about leaving it.
-			h.sendRoom(session, message, nil)
 			if session.UserId() == "" && session.ClientType() != HelloClientTypeInternal {
 				h.startWaitAnonymousSessionRoom(session)
 			}
+			// User was in a room before, so need to notify about leaving it.
+			h.sendRoom(session, message, nil)
 		}
 
 		return

From 18e41f243a83c88cbcdb702b16dbc70578ae1a86 Mon Sep 17 00:00:00 2001
From: Joachim Bauch <bauch@struktur.de>
Date: Thu, 11 Dec 2025 09:59:27 +0100
Subject: [PATCH 2/3] Also ignore "participants" events sent before room was
 joined.

Fix flaky "TestVirtualSessionCustomInCall" under load.
---
 clientsession.go | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/clientsession.go b/clientsession.go
index 5c5d2e9..fa414ec 100644
--- a/clientsession.go
+++ b/clientsession.go
@@ -1424,7 +1424,7 @@ func (s *ClientSession) filterAsyncMessage(msg *AsyncMessage) *ServerMessage {
 				}
 			}
 		case "event":
-			if msg.Message.Event.Target == "room" {
+			if msg.Message.Event.Target == "room" || msg.Message.Event.Target == "participants" {
 				// Can happen mostly during tests where an older room async message
 				// could be received by a subscriber that joined after it was sent.
 				if joined := s.getRoomJoinTime(); joined.IsZero() || msg.SendTime.Before(joined) {

From 550e40f322e95d07f686691ed436ce81e340e7a9 Mon Sep 17 00:00:00 2001
From: Joachim Bauch <bauch@struktur.de>
Date: Thu, 11 Dec 2025 11:00:59 +0100
Subject: [PATCH 3/3] Wait for events to be processed in tests before sending
 between sessions.

Fixes flaky "TestClientControlToSessionId" under load which could send to
a session before the events subscription was processed completely.
---
 async_events_test.go | 18 ++++++++++++++++++
 hub_test.go          |  8 ++++++++
 2 files changed, 26 insertions(+)

diff --git a/async_events_test.go b/async_events_test.go
index 9cf2c5f..107a41d 100644
--- a/async_events_test.go
+++ b/async_events_test.go
@@ -83,3 +83,21 @@ func getLoopbackAsyncEventsForTest(t *testing.T) AsyncEvents {
 	})
 	return events
 }
+
+func waitForAsyncEventsFlushed(ctx context.Context, t *testing.T, events AsyncEvents) {
+	t.Helper()
+
+	nats, ok := (events.(*asyncEventsNats))
+	if !ok {
+		// Only can wait for NATS events.
+		return
+	}
+
+	client, ok := nats.client.(*natsClient)
+	if !ok {
+		// The loopback NATS clients is executing all events synchronously.
+		return
+	}
+
+	assert.NoError(t, client.conn.FlushWithContext(ctx))
+}
diff --git a/hub_test.go b/hub_test.go
index 43fa737..e8ec61a 100644
--- a/hub_test.go
+++ b/hub_test.go
@@ -1985,6 +1985,10 @@ func TestClientMessageToSessionId(t *testing.T) {
 			client2, hello2 := NewTestClientWithHello(ctx, t, server2, hub2, testDefaultUserId+"2")
 			require.NotEqual(hello1.Hello.SessionId, hello2.Hello.SessionId)
 
+			// Make sure the session subscription events are processed.
+			waitForAsyncEventsFlushed(ctx, t, hub1.events)
+			waitForAsyncEventsFlushed(ctx, t, hub2.events)
+
 			recipient1 := MessageClientMessageRecipient{
 				Type:      "session",
 				SessionId: hello1.Hello.SessionId,
@@ -2042,6 +2046,10 @@ func TestClientControlToSessionId(t *testing.T) {
 			client2, hello2 := NewTestClientWithHello(ctx, t, server2, hub2, testDefaultUserId+"2")
 			require.NotEqual(hello1.Hello.SessionId, hello2.Hello.SessionId)
 
+			// Make sure the session subscription events are processed.
+			waitForAsyncEventsFlushed(ctx, t, hub1.events)
+			waitForAsyncEventsFlushed(ctx, t, hub2.events)
+
 			recipient1 := MessageClientMessageRecipient{
 				Type:      "session",
 				SessionId: hello1.Hello.SessionId,