Fixed enter member from internal presence map data race issue

ably/proto_presence_message_test.go

@@ -926,7 +926,7 @@ func Test_internal_presencemap_RTP17(t *testing.T) {
 		presenceMsgCh = make(chan *ably.PresenceMessage, 16)
 
 		c, _ = ably.NewRealtime(
-			ably.WithToken("fake:token"),
+			ably.WithKey("Auth:Key"),
 			ably.WithAutoConnect(false),
 			ably.WithChannelRetryTimeout(channelRetryTimeout),
 			ably.WithRealtimeRequestTimeout(realtimeRequestTimeout),
@@ -1231,6 +1231,6 @@ func Test_internal_presencemap_RTP17(t *testing.T) {
 
 		// Enter from internal map
 		// ablytest.Soon.Recv(t, nil, out, t.Fatalf)
-		// ablytest.Instantly.Recv(t, nil, out, t.Fatalf)
+		// ablytest.Soon.Recv(t, nil, out, t.Fatalf)
 	})
 }

ably/realtime_presence.go

@@ -147,16 +147,23 @@ func syncSerial(msg *protocolMessage) (noChannelSerial bool, syncSequenceId stri
 
 func (pres *RealtimePresence) enterMembersFromInternalPresenceMap() {
 	pres.mtx.Lock()
-	internalMembers := pres.internalMembers
+	internalMembers := make([]*PresenceMessage, len(pres.internalMembers))
+	indexCounter := 0
+	for _, member := range pres.internalMembers {
+		internalMembers[indexCounter] = member
+		indexCounter = indexCounter + 1
+	}
 	pres.mtx.Unlock()
 	for _, member := range internalMembers {
+		ctx, cancel := context.WithTimeout(context.Background(), 2*time.Minute)
 		// RTP17g
-		err := pres.EnterClient(context.Background(), member.ClientID, member.Data)
+		err := pres.EnterClient(ctx, member.ClientID, member.Data)
 		// RTP17e
 		if err != nil {
 			pres.channel.log().Errorf("Error for internal member presence enter with id %v, clientId %v, err %v", member.ID, member.ClientID, err)
 			pres.channel.emitErrorUpdate(newError(91004, err), true)
 		}
+		cancel()
 	}
 }