Don't remember cluster node for the PubSub

cluster.go

@@ -1522,40 +1522,46 @@ func (c *ClusterClient) txPipelineReadQueued(
 	return nil
 }
 
-func (c *ClusterClient) pubSub(channels []string) *PubSub {
+func (c *ClusterClient) pubSub() *PubSub {
 	var node *clusterNode
 	pubsub := &PubSub{
 		opt: c.opt.clientOptions(),
 
 		newConn: func(channels []string) (*pool.Conn, error) {
-			if node == nil {
-				var slot int
-				if len(channels) > 0 {
-					slot = hashtag.Slot(channels[0])
-				} else {
-					slot = -1
-				}
-
-				masterNode, err := c.slotMasterNode(slot)
-				if err != nil {
-					return nil, err
-				}
-				node = masterNode
+			if node != nil {
+				panic("node != nil")
 			}
-			return node.Client.newConn()
+
+			slot := hashtag.Slot(channels[0])
+
+			var err error
+			node, err = c.slotMasterNode(slot)
+			if err != nil {
+				return nil, err
+			}
+
+			cn, err := node.Client.newConn()
+			if err != nil {
+				return nil, err
+			}
+
+			return cn, nil
 		},
 		closeConn: func(cn *pool.Conn) error {
-			return node.Client.connPool.CloseConn(cn)
+			err := node.Client.connPool.CloseConn(cn)
+			node = nil
+			return err
 		},
 	}
 	pubsub.init()
+
 	return pubsub
 }
 
 // Subscribe subscribes the client to the specified channels.
 // Channels can be omitted to create empty subscription.
 func (c *ClusterClient) Subscribe(channels ...string) *PubSub {
-	pubsub := c.pubSub(channels)
+	pubsub := c.pubSub()
 	if len(channels) > 0 {
 		_ = pubsub.Subscribe(channels...)
 	}
@@ -1565,7 +1571,7 @@ func (c *ClusterClient) Subscribe(channels ...string) *PubSub {
 // PSubscribe subscribes the client to the given patterns.
 // Patterns can be omitted to create empty subscription.
 func (c *ClusterClient) PSubscribe(channels ...string) *PubSub {
-	pubsub := c.pubSub(channels)
+	pubsub := c.pubSub()
 	if len(channels) > 0 {
 		_ = pubsub.PSubscribe(channels...)
 	}