fix: listener deletion (#73)

pkg/collectconfig/executor/logstream/logstream_g.go

@@ -147,10 +147,16 @@ func (f *GLogStream) RemoveListener(listener Listener, cursor int64) {
 
 	listeners := make([]Listener, 0, len(f.Listeners))
 	for _, l := range f.Listeners {
+		// The implementations of Listener must not be empty structs.
+		// They will result in same object address when their instances are converted to Listener interface,
+		// which leads to the following 'l!=listener' always returns false
 		if l != listener {
 			listeners = append(listeners, l)
 		}
 	}
+	if x := len(f.Listeners) - len(listeners); x > 1 {
+		logger.Errorz("remove multi listeners", zap.String("key", f.Key), zap.Int("old", len(f.Listeners)), zap.Int("new", len(listeners)))
+	}
 	f.Listeners = listeners
 
 	for i := cursor; i < f.Cursor; i++ {

pkg/collectconfig/executor/pipeline.go

@@ -35,7 +35,9 @@ const (
 )
 
 type (
-	listenerImpl struct{}
+	listenerImpl struct {
+		_ int
+	}
 
 	// LogPipeline is responsible for detecting log inputs(see inputsManager) , scheduling pulling logs task, and put logs to consumer.
 	LogPipeline struct {
@@ -162,7 +164,6 @@ func (iw *inputWrapper) read() (*logstream.ReadResponse, int64, error) {
 
 func (l *listenerImpl) Changed(ls logstream.LogStream, lcursor int64) {
 }
-
 func (p *LogPipeline) Key() string {
 	return p.st.CT.Key
 }