Merge pull request #147 from getamis/bug/istanbul-crash-in-integration-test

consensus/istanbul: clear state in handler goroutine and stop core synchronuously

Author: alanchchen

consensus/istanbul/core/core.go

@@ -39,6 +39,7 @@ func New(backend istanbul.Backend, config *istanbul.Config) Engine {
 		config:             config,
 		address:            backend.Address(),
 		state:              StateAcceptRequest,
+		handlerWg:          new(sync.WaitGroup),
 		logger:             log.New("address", backend.Address()),
 		backend:            backend,
 		backlogs:           make(map[istanbul.Validator]*prque.Prque),
@@ -75,7 +76,8 @@ type core struct {
 	backlogs   map[istanbul.Validator]*prque.Prque
 	backlogsMu *sync.Mutex
 
-	current *roundState
+	current   *roundState
+	handlerWg *sync.WaitGroup
 
 	roundChangeSet   *roundChangeSet
 	roundChangeTimer *time.Timer

consensus/istanbul/core/handler.go

@@ -38,7 +38,9 @@ func (c *core) Start() error {
 func (c *core) Stop() error {
 	c.stopTimer()
 	c.unsubscribeEvents()
-	c.current = nil
+
+	// Make sure the handler goroutine exits
+	c.handlerWg.Wait()
 	return nil
 }
 
@@ -69,6 +71,14 @@ func (c *core) unsubscribeEvents() {
 }
 
 func (c *core) handleEvents() {
+	// Clear state
+	defer func() {
+		c.current = nil
+		c.handlerWg.Done()
+	}()
+
+	c.handlerWg.Add(1)
+
 	for {
 		select {
 		case event, ok := <-c.events.Chan():