From 850045d6a69756aafe383c7bf1067f449c9c84e3 Mon Sep 17 00:00:00 2001
From: Sergey Shcherbina <trytoheal@gmail.com>
Date: Thu, 29 Sep 2016 15:12:35 +0500
Subject: [PATCH] Use appendIfNotExists instead of append. Fixed bug when
 connection loss to server leads to exponential grow of channels and patterns
 array in PubSub in every reconnect

---
 pubsub.go | 21 +++++++++++++++++++--
 1 file changed, 19 insertions(+), 2 deletions(-)

diff --git a/pubsub.go b/pubsub.go
index 1d1fc93..de8d35c 100644
--- a/pubsub.go
+++ b/pubsub.go
@@ -43,7 +43,7 @@ func (c *PubSub) subscribe(redisCmd string, channels ...string) error {
 func (c *PubSub) Subscribe(channels ...string) error {
 	err := c.subscribe("SUBSCRIBE", channels...)
 	if err == nil {
-		c.channels = append(c.channels, channels...)
+		c.channels = appendIfNotExists(c.channels, channels...)
 		c.nsub += len(channels)
 	}
 	return err
@@ -53,7 +53,7 @@ func (c *PubSub) Subscribe(channels ...string) error {
 func (c *PubSub) PSubscribe(patterns ...string) error {
 	err := c.subscribe("PSUBSCRIBE", patterns...)
 	if err == nil {
-		c.patterns = append(c.patterns, patterns...)
+		c.patterns = appendIfNotExists(c.patterns, patterns...)
 		c.nsub += len(patterns)
 	}
 	return err
@@ -74,6 +74,23 @@ func remove(ss []string, es ...string) []string {
 	return ss
 }
 
+func appendIfNotExists(ss []string, es ...string) []string { 
+	for _, e := range es {
+		found := false
+		for _, s := range ss {
+			if s == e {
+				found = true
+				break
+			}
+		}	
+		
+		if !found {
+			ss = append(ss, e)
+		}
+	}
+	return ss
+}
+
 // Unsubscribes the client from the given channels, or from all of
 // them if none is given.
 func (c *PubSub) Unsubscribe(channels ...string) error {