From 4b8438b9720928b9d97eca4577ff0d7789934379 Mon Sep 17 00:00:00 2001
From: stong <498327580@qq.com>
Date: Tue, 19 Sep 2023 09:49:31 +0800
Subject: [PATCH]  Clean up resources related to the topic if there are no
 subscribers (#391)

---
 pubsub/gochannel/pubsub.go | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/pubsub/gochannel/pubsub.go b/pubsub/gochannel/pubsub.go
index 0d4fc61c7..5dd5a02fd 100644
--- a/pubsub/gochannel/pubsub.go
+++ b/pubsub/gochannel/pubsub.go
@@ -205,7 +205,14 @@ func (g *GoChannel) Subscribe(ctx context.Context, topic string) (<-chan *messag
 		s.Close()
 
 		g.subscribersLock.Lock()
-		defer g.subscribersLock.Unlock()
+		defer func() {
+			// if there are no subscribers, clean up any resources related to the topic
+			if len(g.subscribers[topic]) == 0 {
+				delete(g.subscribers, topic)
+				g.subscribersByTopicLock.Delete(topic)
+			}
+			g.subscribersLock.Unlock()
+		}()
 
 		subLock, _ := g.subscribersByTopicLock.Load(topic)
 		subLock.(*sync.Mutex).Lock()