fix: wal may panics when context canceled (#40265)

issue: #40264

- wal may panics when context canceled
- scanner may data race when closing

Signed-off-by: chyezh <chyezh@outlook.com>

internal/streamingnode/server/wal/adaptor/scanner_adaptor.go

@@ -98,7 +98,9 @@ func (s *scannerAdaptorImpl) execute() {
 	s.logger.Info("scanner start background task")
 
 	msgChan := make(chan message.ImmutableMessage)
+
 	ch := make(chan struct{})
+	defer func() { <-ch }()
 	// TODO: optimize the extra goroutine here after msgstream is removed.
 	go func() {
 		defer close(ch)
@@ -116,9 +118,6 @@ func (s *scannerAdaptorImpl) execute() {
 		return
 	}
 	s.logger.Warn("the consuming event loop of scanner is closed with unexpected error", zap.Error(err))
-
-	// waiting for the produce event loop to close.
-	<-ch
 }
 
 // produceEventLoop produces the message from the wal and write ahead buffer.

internal/streamingnode/server/wal/interceptors/timetick/timetick_interceptor.go

@@ -41,10 +41,14 @@ func (impl *timeTickAppendInterceptor) Ready() <-chan struct{} {
 
 // Do implements AppendInterceptor.
 func (impl *timeTickAppendInterceptor) DoAppend(ctx context.Context, msg message.MutableMessage, append interceptors.Append) (msgID message.MessageID, err error) {
+	cm, err := impl.operator.MVCCManager(ctx)
+	if err != nil {
+		return nil, err
+	}
+
 	defer func() {
 		if err == nil {
 			// the cursor manager should beready since the timetick interceptor is ready.
-			cm, _ := impl.operator.MVCCManager(ctx)
 			cm.UpdateMVCC(msg)
 		}
 	}()