PLT-3736 Fixed duplicated create_direct api calls not returning the existing channel (#4745)

* Fixed duplicated create_direct api calls not returning the existing channel

* Added unit tests for duplicated create_direct api calls

store/sql_channel_store.go

@@ -210,7 +210,7 @@ func (s SqlChannelStore) saveChannelT(transaction *gorp.Transaction, channel *mo
 	if err := transaction.Insert(channel); err != nil {
 		if IsUniqueConstraintError(err.Error(), []string{"Name", "channels_name_teamid_key"}) {
 			dupChannel := model.Channel{}
-			s.GetMaster().SelectOne(&dupChannel, "SELECT * FROM Channels WHERE TeamId = :TeamId AND Name = :Name AND DeleteAt > 0", map[string]interface{}{"TeamId": channel.TeamId, "Name": channel.Name})
+			s.GetMaster().SelectOne(&dupChannel, "SELECT * FROM Channels WHERE TeamId = :TeamId AND Name = :Name", map[string]interface{}{"TeamId": channel.TeamId, "Name": channel.Name})
 			if dupChannel.DeleteAt > 0 {
 				result.Err = model.NewLocAppError("SqlChannelStore.Save", "store.sql_channel.save_channel.previously.app_error", nil, "id="+channel.Id+", "+err.Error())
 			} else {

store/sql_channel_store_test.go

@@ -88,6 +88,23 @@ func TestChannelStoreSaveDirectChannel(t *testing.T) {
 		t.Fatal("shouldn't be able to update from save")
 	}
 
+	// Attempt to save a direct channel that already exists
+	o1a := model.Channel{
+		TeamId:      o1.TeamId,
+		DisplayName: o1.DisplayName,
+		Name:        o1.Name,
+		Type:        o1.Type,
+	}
+
+	if result := <-store.Channel().SaveDirectChannel(&o1a, &m1, &m2); result.Err == nil {
+		t.Fatal("should've failed to save a duplicate direct channel")
+	} else if result.Err.Id != CHANNEL_EXISTS_ERROR {
+		t.Fatal("should've returned CHANNEL_EXISTS_ERROR")
+	} else if returned := result.Data.(*model.Channel); returned.Id != o1.Id {
+		t.Fatal("should've returned original channel when saving a duplicate direct channel")
+	}
+
+	// Attempt to save a non-direct channel
 	o1.Id = ""
 	o1.Name = "a" + model.NewId() + "b"
 	o1.Type = model.CHANNEL_OPEN