fix: 停机先停接受并等待循环再断开 MQTT

cmd/nixmsg/uplink_integration_test.go

@@ -186,6 +186,7 @@ type mqttSess struct {
 	inbox      []map[string]any
 	closed     bool
 	done       chan struct{}
+	shutdownCh chan byte
 }
 
 type appResp struct {
@@ -201,7 +202,19 @@ func mqttSessionLogin(t *testing.T, httpBase, endpointID, password string) *mqtt
 	if err != nil {
 		t.Fatalf("dial: %v", err)
 	}
-	s := &mqttSess{t: t, mc: mc, endpointID: endpointID, pktID: 10, done: make(chan struct{})}
+	s := &mqttSess{t: t, mc: mc, endpointID: endpointID, pktID: 10, done: make(chan struct{}), shutdownCh: make(chan byte, 1)}
+	s.connectSubscribeHello(password)
+	go s.readLoop()
+	return s
+}
+
+func mqttSessionLoginTCP(t *testing.T, addr, endpointID, password string) *mqttSess {
+	t.Helper()
+	mc, err := harness.DialMQTTTCP(addr, 10*time.Second)
+	if err != nil {
+		t.Fatalf("dial tcp: %v", err)
+	}
+	s := &mqttSess{t: t, mc: mc, endpointID: endpointID, pktID: 10, done: make(chan struct{}), shutdownCh: make(chan byte, 1)}
 	s.connectSubscribeHello(password)
 	go s.readLoop()
 	return s
@@ -344,6 +357,13 @@ func (s *mqttSess) handlePacket(raw []byte) map[string]any {
 	switch typ {
 	case packets.Puback, packets.Pingresp, packets.Suback:
 		return nil
+	case packets.Disconnect:
+		reason := byte(0)
+		if _, n, err := decodeRemainingLength(raw[1:]); err == nil && 1+n < len(raw) {
+			reason = raw[1+n]
+		}
+		s.noteShutdown(reason)
+		return nil
 	case packets.Publish:
 		payload, err := decodePublishPayload(raw)
 		if err != nil {
@@ -446,6 +466,28 @@ func (s *mqttSess) takeMatching(pred func(map[string]any) bool) map[string]any {
 	return nil
 }
 
+func (s *mqttSess) noteShutdown(reason byte) {
+	if s.shutdownCh == nil {
+		return
+	}
+	select {
+	case s.shutdownCh <- reason:
+	default:
+	}
+}
+
+func (s *mqttSess) disconnectReason(timeout time.Duration) (byte, bool) {
+	if s.shutdownCh == nil {
+		return 0, false
+	}
+	select {
+	case r := <-s.shutdownCh:
+		return r, true
+	case <-time.After(timeout):
+		return 0, false
+	}
+}
+
 func drainEvents(t *testing.T, s *mqttSess, d time.Duration) {
 	t.Helper()
 	deadline := time.Now().Add(d)