allowing to pass an has many relationship on create record. Fixes #1497

packages/ember-data/lib/system/relationships/has-many.js

@@ -2,6 +2,7 @@
   @module ember-data
 */
 
+import computedPolyfill from "ember-data/utils/computed-polyfill";
 import Model from "ember-data/system/model";
 import normalizeModelName from "ember-data/system/normalize-model-name";
 
@@ -120,10 +121,18 @@ function hasMany(type, options) {
     key: null
   };
 
-  return Ember.computed(function(key) {
-    var relationship = this._relationships[key];
-    return relationship.getRecords();
-  }).meta(meta).readOnly();
+  return computedPolyfill({
+    get: function(key) {
+      var relationship = this._relationships[key];
+      return relationship.getRecords();
+    },
+    set: function(key, records) {
+      var relationship = this._relationships[key];
+      relationship.clear();
+      relationship.addRecords(records);
+      return relationship.getRecords();
+    }
+  }).meta(meta);
 }
 
 Model.reopen({

packages/ember-data/tests/integration/adapter/rest-adapter-test.js

@@ -369,8 +369,7 @@ test("create - a serializer's attribute mapping takes precedence over keyForRela
 
   run(function() {
     var comment = store.createRecord('comment', { id: "a-comment-id", name: "First!" });
-    var post = store.createRecord('post', { id: "some-uuid", name: "The Parley Letter" });
-    post.get('comments').pushObject(comment);
+    var post = store.createRecord('post', { id: "some-uuid", name: "The Parley Letter", comments: [comment] });
 
     post.save().then(async(function(post) {
       deepEqual(passedHash.data, { post: { opinions: ["a-comment-id"], id: "some-uuid", name: "The Parley Letter" } });

packages/ember-data/tests/integration/relationships/has-many-test.js

@@ -892,19 +892,19 @@ test("When a record is created on the client, its async hasMany arrays should be
   });
 });
 
-test("a records SYNC HM relationship property is readOnly", function() {
+test("we can set records SYNC HM relationship", function() {
   expect(1);
   var post = run(function() {
     return env.store.createRecord('post');
   });
-
-  raises(function() {
-    post.set('comments');
-  }, 'Cannot Set: comments on: ' + Ember.inspect(post));
+  run(function() {
+    post.set('comments', env.store.pushMany('comment', [{ id: 1, body: "First" }, { id: 2, body: "Second" }]));
+  });
+  equal(get(post, 'comments.length'), 2, "we can set HM relationship");
 });
 
 
-test("a records ASYNC HM relationship property is readOnly", function() {
+test("We can set records ASYNC HM relationship", function() {
   expect(1);
   Post.reopen({
     comments: DS.hasMany('comment', { async: true })
@@ -913,10 +913,13 @@ test("a records ASYNC HM relationship property is readOnly", function() {
   var post = run(function() {
     return env.store.createRecord('post');
   });
+  run(function() {
+    post.set('comments', env.store.pushMany('comment', [{ id: 1, body: "First" }, { id: 2, body: "Second" }]));
+  });
 
-  raises(function() {
-    run(post, 'set', 'comments');
-  }, 'Cannot Set: comments on: ' + Ember.inspect(post));
+  post.get('comments').then(async(function(comments) {
+    equal(comments.get('length')  , 2, "we can set async HM relationship");
+  }));
 });
 
 test("When a record is saved, its unsaved hasMany records should be kept", function () {

packages/ember-data/tests/unit/store/create-record-test.js

@@ -1,13 +1,23 @@
-var store, container, Record;
+var store, container, Record, Storage;
 var run = Ember.run;
 
 module("unit/store/createRecord - Store creating records", {
   setup: function() {
-    store = createStore({ adapter: DS.Adapter.extend() });
 
     Record = DS.Model.extend({
       title: DS.attr('string')
     });
+
+    Storage = DS.Model.extend({
+      name: DS.attr('name'),
+      records: DS.hasMany('record')
+    });
+
+    store = createStore({
+      adapter: DS.Adapter.extend(),
+      record: Record,
+      storage: Storage
+    });
   }
 });
 
@@ -21,6 +31,18 @@ test("doesn't modify passed in properties hash", function() {
   deepEqual(attributes, { foo: 'bar' }, "The properties hash is not modified");
 });
 
+test("allow passing relationships as well as attributes", function() {
+  var records, storage;
+  run(function() {
+    records = store.pushMany(Record, [{ id: 1, title: "it's a beautiful day" }, { id: 2, title: "it's a beautiful day" }]);
+    storage = store.createRecord(Storage, { name: 'Great store', records: records });
+  });
+
+  equal(storage.get('name'), 'Great store', "The attribute is well defined");
+  equal(storage.get('records').findBy('id', '1'), Ember.A(records).findBy('id', '1'), "Defined relationships are allowed in createRecord");
+  equal(storage.get('records').findBy('id', '2'), Ember.A(records).findBy('id', '2'), "Defined relationships are allowed in createRecord");
+});
+
 module("unit/store/createRecord - Store with models by dash", {
   setup: function() {
     var env = setupStore({