karmada-search: Fix lock race affects watch RestChan not close, causi…

…ng client watch api to hang

Signed-off-by: xigang <wangxiang2014@gmail.com>

pkg/search/proxy/store/util.go

@@ -172,16 +172,16 @@ type decoratedWatcher struct {
 }
 
 type watchMux struct {
-	lock    sync.RWMutex
-	sources []decoratedWatcher
-	result  chan watch.Event
-	done    chan struct{}
+	lock           sync.RWMutex
+	sources        []decoratedWatcher
+	result         chan watch.Event
+	done           chan struct{}
 }
 
 func newWatchMux() *watchMux {
 	return &watchMux{
-		result: make(chan watch.Event),
-		done:   make(chan struct{}),
+		result:         make(chan watch.Event, 100),
+		done:           make(chan struct{}),
 	}
 }
 
@@ -227,6 +227,7 @@ func (w *watchMux) Stop() {
 func (w *watchMux) startWatchSource(source watch.Interface, decorator func(watch.Event)) {
 	defer source.Stop()
 	defer w.Stop()
+
 	for {
 		var copyEvent watch.Event
 		select {
@@ -250,13 +251,10 @@ func (w *watchMux) startWatchSource(source watch.Interface, decorator func(watch
 		}
 
 		func() {
-			w.lock.RLock()
-			defer w.lock.RUnlock()
 			select {
 			case <-w.done:
 				return
-			default:
-				w.result <- copyEvent
+			case w.result <- copyEvent:
 			}
 		}()
 	}