[BUGFIX beta] Fix createRecord creating two records

addon/-private/system/model/internal-model.js

@@ -334,7 +334,7 @@ export default class InternalModel {
     return this.currentState.dirtyType;
   }
 
-  getRecord(properties) {
+  getRecord() {
     if (!this._record && !this._isDematerializing) {
       heimdall.increment(materializeRecord);
       let token = heimdall.start('InternalModel.getRecord');
@@ -350,10 +350,6 @@ export default class InternalModel {
         adapterError: this.error
       };
 
-      if (typeof properties === 'object' && properties !== null) {
-        emberAssign(createOptions, properties);
-      }
-
       if (setOwner) {
         // ensure that `getOwner(this)` works inside a model instance
         setOwner(createOptions, getOwner(this.store));

addon/-private/system/store.js

@@ -358,7 +358,8 @@ Store = Service.extend({
 
     let internalModel = this._buildInternalModel(normalizedModelName, properties.id);
     internalModel.loadedData();
-    let record = internalModel.getRecord(properties);
+    let record = internalModel.getRecord();
+    record.setProperties(properties);
 
     // TODO @runspired this should also be coalesced into some form of internalModel.setState()
     internalModel.eachRelationship((key, descriptor) => {

tests/integration/relationships/one-to-many-test.js

@@ -1452,3 +1452,35 @@ test("Rollbacking attributes of a created record works correctly when the belong
   assert.equal(user.get('accounts.length'), 0, "User does not have the account anymore");
   assert.equal(account.get('user'), null, 'Account does not have the user anymore');
 });
+
+test("createRecord updates inverse record array which has observers", function(assert) {
+
+  env.adapter.findAll = () => {
+    return {
+      data: [{
+        id: '2',
+        type: 'user',
+        attributes: {
+          name: 'Stanley'
+        }
+      }]
+    }
+  };
+
+  return store.findAll('user').then(users => {
+    assert.equal(users.get('length'), 1, 'Exactly 1 user');
+
+    let user = users.get('firstObject');
+    assert.equal(user.get('messages.length'), 0, 'Record array is initially empty');
+
+    // set up an observer
+    user.addObserver('[email protected]', () => {});
+    user.get('messages.firstObject');
+
+    let message = run(() => store.createRecord('message', { user, title: 'EmberFest was great' }));
+    assert.equal(user.get('messages.length'), 1, 'The message is added to the record array');
+
+    let messageFromArray = user.get('messages.firstObject');
+    assert.equal(message, messageFromArray, 'Only one message should be created');
+  });
+});