Take account for the fact the Closed function can be called more than…

… once.

pkg/fswatcher/fswatcher.go

@@ -34,6 +34,7 @@ type FSWatcher struct {
 	onChange           func()
 	mu                 sync.RWMutex
 	stop               chan struct{}
+	isClosed           bool
 	wg                 sync.WaitGroup
 }
 
@@ -70,6 +71,7 @@ func New(filepaths []string, onChange func(), logger *zap.Logger) (*FSWatcher, e
 		fileHashContentMap: make(map[string]string),
 		onChange:           onChange,
 		stop:               make(chan struct{}),
+		isClosed:           false,
 	}
 
 	if err = w.setupWatchedPaths(filepaths); err != nil {
@@ -146,8 +148,11 @@ func (w *FSWatcher) watch() {
 
 // Close closes the watcher and stops the background go routine of FSWatcher.
 func (w *FSWatcher) Close() error {
-	close(w.stop)
-	w.wg.Wait()
+	if !w.isClosed {
+		close(w.stop)
+		w.wg.Wait()
+	}
+	w.isClosed = true
 	return w.watcher.Close()
 }