fix: already subscribe to topic (#231)

liuxinfeng96 · web-flow · commit f346c39113ba · 2023-09-20T10:38:49.000+08:00
diff --git a/conn/channel.go b/conn/channel.go
@@ -752,7 +752,7 @@ func (hc *channelSession) subscribeTopic(topic string, handler func([]byte, *[]b
 	if handler == nil {
 		return errors.New("handler is nil")
 	}
-	if _, ok := hc.topicHandlers[topic]; ok {
+	if oldHandler, ok := hc.topicHandlers[topic]; ok && oldHandler != nil {
 		return errors.New("already subscribed to topic " + topic)
 	}
 	hc.topicMu.Lock()

Original file line number	Diff line number	Diff line change
`@@ -752,7 +752,7 @@ func (hc channelSession) subscribeTopic(topic string, handler func([]byte, []b`
`752`	`752`	`if handler == nil {`
`753`	`753`	`return errors.New("handler is nil")`
`754`	`754`	`}`
`755`		`- if _, ok := hc.topicHandlers[topic]; ok {`
	`755`	`+ if oldHandler, ok := hc.topicHandlers[topic]; ok && oldHandler != nil {`
`756`	`756`	`return errors.New("already subscribed to topic " + topic)`
`757`	`757`	`}`
`758`	`758`	`hc.topicMu.Lock()`