From 4a907b0a18a02ef45cc597730caaf83e7edd4618 Mon Sep 17 00:00:00 2001
From: Raymond Feng <raymond@strongloop.com>
Date: Thu, 8 May 2014 15:46:39 -0700
Subject: [PATCH] Remove the undefined property to avoid mongodb upsert
 overwrite

---
 lib/dao.js | 20 ++++++++++++++------
 1 file changed, 14 insertions(+), 6 deletions(-)

diff --git a/lib/dao.js b/lib/dao.js
index 267d609e..4cf85929 100644
--- a/lib/dao.js
+++ b/lib/dao.js
@@ -214,25 +214,33 @@ function stillConnecting(dataSource, obj, args) {
  * @param {Function} callback The callback function (optional).
  */
 DataAccessObject.upsert = DataAccessObject.updateOrCreate = function upsert(data, callback) {
-  if (stillConnecting(this.getDataSource(), this, arguments)) return;
+  if (stillConnecting(this.getDataSource(), this, arguments)) {
+    return;
+  }
 
   var Model = this;
-  if (!getIdValue(this, data)) return this.create(data, callback);
+  if (!getIdValue(this, data)) {
+    return this.create(data, callback);
+  }
   if (this.getDataSource().connector.updateOrCreate) {
     var inst = new Model(data);
-    this.getDataSource().connector.updateOrCreate(Model.modelName, inst.toObject(true), function (err, data) {
+    var update = inst.toObject(true);
+    update = removeUndefined(update);
+    this.getDataSource().connector.updateOrCreate(Model.modelName, update, function (err, data) {
       var obj;
-      if (data) {
+      if (data && !(data instanceof Model)) {
         inst._initProperties(data);
         obj = inst;
       } else {
-        obj = null;
+        obj = data;
       }
       callback(err, obj);
     });
   } else {
     this.findById(getIdValue(this, data), function (err, inst) {
-      if (err) return callback(err);
+      if (err) {
+        return callback(err);
+      }
       if (inst) {
         inst.updateAttributes(data, callback);
       } else {