Fixing race in update channel (mattermost#7269)

* Fixing race in update channel

* Switching to struct copy

model/channel.go

@@ -53,6 +53,11 @@ type ChannelPatch struct {
 	Purpose     *string `json:"purpose"`
 }
 
+func (o *Channel) DeepCopy() *Channel {
+	copy := *o
+	return &copy
+}
+
 func (o *Channel) ToJson() string {
 	b, err := json.Marshal(o)
 	if err != nil {

model/channel_test.go

@@ -27,6 +27,15 @@ func TestChannelJson(t *testing.T) {
 	}
 }
 
+func TestChannelCopy(t *testing.T) {
+	o := Channel{Id: NewId(), Name: NewId()}
+	ro := o.DeepCopy()
+
+	if o.Id != ro.Id {
+		t.Fatal("Ids do not match")
+	}
+}
+
 func TestChannelPatch(t *testing.T) {
 	p := &ChannelPatch{Name: new(string), DisplayName: new(string), Header: new(string), Purpose: new(string)}
 	*p.Name = NewId()

store/sql_channel_store.go

@@ -405,7 +405,7 @@ func (s SqlChannelStore) get(id string, master bool, allowFromCache bool) StoreC
 				if metrics != nil {
 					metrics.IncrementMemCacheHitCounter("Channel")
 				}
-				result.Data = cacheItem.(*model.Channel)
+				result.Data = (cacheItem.(*model.Channel)).DeepCopy()
 				storeChannel <- result
 				close(storeChannel)
 				return