routing: shutdown chanrouter correctly.

chainntnfs/bitcoindnotify/bitcoind.go

@@ -151,7 +151,12 @@ func (b *BitcoindNotifier) Stop() error {
 
 		close(epochClient.epochChan)
 	}
-	b.txNotifier.TearDown()
+
+	// The txNotifier is only initialized in the start method therefore we
+	// need to make sure we don't access a nil pointer here.
+	if b.txNotifier != nil {
+		b.txNotifier.TearDown()
+	}
 
 	// Stop the mempool notifier.
 	b.memNotifier.TearDown()

chainntnfs/neutrinonotify/neutrino.go

@@ -152,7 +152,12 @@ func (n *NeutrinoNotifier) Stop() error {
 
 		close(epochClient.epochChan)
 	}
-	n.txNotifier.TearDown()
+
+	// The txNotifier is only initialized in the start method therefore we
+	// need to make sure we don't access a nil pointer here.
+	if n.txNotifier != nil {
+		n.txNotifier.TearDown()
+	}
 
 	return nil
 }

chanfitness/chaneventstore.go

@@ -226,11 +226,17 @@ func (c *ChannelEventStore) Stop() error {
 
 	// Stop the ticker after the goroutine reading from it has exited, to
 	// avoid a race.
-	c.cfg.FlapCountTicker.Stop()
+	var err error
+	if c.cfg.FlapCountTicker == nil {
+		err = fmt.Errorf("ChannelEventStore FlapCountTicker not " +
+			"initialized")
+	} else {
+		c.cfg.FlapCountTicker.Stop()
+	}
 
 	log.Debugf("ChannelEventStore shutdown complete")
 
-	return nil
+	return err
 }
 
 // addChannel checks whether we are already tracking a channel's peer, creates a

discovery/gossiper.go

@@ -753,7 +753,12 @@ func (d *AuthenticatedGossiper) stop() {
 	log.Debug("Authenticated Gossiper is stopping")
 	defer log.Debug("Authenticated Gossiper stopped")
 
-	d.blockEpochs.Cancel()
+	// `blockEpochs` is only initialized in the start routine so we make
+	// sure we don't panic here in the case where the `Stop` method is
+	// called when the `Start` method does not complete.
+	if d.blockEpochs != nil {
+		d.blockEpochs.Cancel()
+	}
 
 	d.syncMgr.Stop()
 

htlcswitch/interceptable_switch.go

@@ -242,7 +242,11 @@ func (s *InterceptableSwitch) Stop() error {
 	close(s.quit)
 	s.wg.Wait()
 
-	s.blockEpochStream.Cancel()
+	// We need to check whether the start routine run and initialized the
+	// `blockEpochStream`.
+	if s.blockEpochStream != nil {
+		s.blockEpochStream.Cancel()
+	}
 
 	log.Debug("InterceptableSwitch shutdown complete")
 

htlcswitch/link.go

@@ -562,14 +562,18 @@ func (l *channelLink) Stop() {
 	}
 
 	// Ensure the channel for the timer is drained.
-	if !l.updateFeeTimer.Stop() {
-		select {
-		case <-l.updateFeeTimer.C:
-		default:
+	if l.updateFeeTimer != nil {
+		if !l.updateFeeTimer.Stop() {
+			select {
+			case <-l.updateFeeTimer.C:
+			default:
+			}
 		}
 	}
 
-	l.hodlQueue.Stop()
+	if l.hodlQueue != nil {
+		l.hodlQueue.Stop()
+	}
 
 	close(l.quit)
 	l.wg.Wait()

invoices/invoiceregistry.go

@@ -261,15 +261,21 @@ func (i *InvoiceRegistry) Stop() error {
 	log.Info("InvoiceRegistry shutting down...")
 	defer log.Debug("InvoiceRegistry shutdown complete")
 
-	i.expiryWatcher.Stop()
+	var err error
+	if i.expiryWatcher == nil {
+		err = fmt.Errorf("InvoiceRegistry expiryWatcher is not " +
+			"initialized")
+	} else {
+		i.expiryWatcher.Stop()
+	}
 
 	close(i.quit)
 
 	i.wg.Wait()
 
 	log.Debug("InvoiceRegistry shutdown complete")
 
-	return nil
+	return err
 }
 
 // invoiceEvent represents a new event that has modified on invoice on disk.

lnwallet/chainfee/estimator.go

@@ -884,7 +884,9 @@ func (w *WebAPIEstimator) Stop() error {
 		return nil
 	}
 
-	w.updateFeeTicker.Stop()
+	if w.updateFeeTicker != nil {
+		w.updateFeeTicker.Stop()
+	}
 
 	close(w.quit)
 	w.wg.Wait()

server.go

@@ -2105,6 +2105,9 @@ func (s *server) Start() error {
 			}
 		}
 
+		// chanSubSwapper must be started after the `channelNotifier`
+		// because it depends on channel events as a synchronization
+		// point.
 		cleanup = cleanup.add(s.chanSubSwapper.Stop)
 		if err := s.chanSubSwapper.Start(); err != nil {
 			startErr = err

tor/controller.go

@@ -186,6 +186,10 @@ func (c *Controller) Stop() error {
 	// Reset service ID.
 	c.activeServiceID = ""
 
+	if c.conn == nil {
+		return fmt.Errorf("no connection available to the tor server")
+	}
+
 	return c.conn.Close()
 }