Lazily materialize DS.Models for app code, use InternalModel inside ED otherwise

packages/ember-data/lib/main.js

@@ -19,6 +19,8 @@ import "ember-data/ext/date";
 
 import normalizeModelName from "ember-data/system/normalize-model-name";
 
+import InternalModel from "ember-data/system/model/internal-model";
+
 import {
   PromiseArray,
   PromiseObject,
@@ -85,6 +87,7 @@ DS.RootState = RootState;
 DS.attr      = attr;
 DS.Errors    = Errors;
 
+DS.InternalModel = InternalModel;
 DS.Snapshot = Snapshot;
 
 DS.Adapter      = Adapter;

packages/ember-data/lib/system/many-array.js

@@ -6,6 +6,7 @@ import { PromiseArray } from "ember-data/system/promise-proxies";
 var get = Ember.get;
 var set = Ember.set;
 var filter = Ember.ArrayPolyfills.filter;
+var map = Ember.EnumerableUtils.map;
 
 /**
   A `ManyArray` is a `MutableArray` that represents the contents of a has-many
@@ -57,19 +58,23 @@ export default Ember.Object.extend(Ember.MutableArray, Ember.Evented, {
   length: 0,
 
   objectAt: function(index) {
-    return this.currentState[index];
+    //Ember observers such as 'firstObject', 'lastObject' might do out of bounds accesses
+    if (!this.currentState[index]) {
+      return undefined;
+    }
+    return this.currentState[index].getRecord();
   },
 
   flushCanonical: function() {
     //TODO make this smarter, currently its plenty stupid
-    var toSet = filter.call(this.canonicalState, function(record) {
-      return !record.get('isDeleted');
+    var toSet = filter.call(this.canonicalState, function(internalModel) {
+      return !internalModel.isDeleted();
     });
 
     //a hack for not removing new records
     //TODO remove once we have proper diffing
-    var newRecords = this.currentState.filter(function(record) {
-      return record.get('isNew');
+    var newRecords = this.currentState.filter(function(internalModel) {
+      return internalModel.isNew();
     });
     toSet = toSet.concat(newRecords);
     var oldLength = this.length;
@@ -143,7 +148,7 @@ export default Ember.Object.extend(Ember.MutableArray, Ember.Evented, {
       this.get('relationship').removeRecords(records);
     }
     if (objects) {
-      this.get('relationship').addRecords(objects, idx);
+      this.get('relationship').addRecords(map(objects, function(obj) { return obj._internalModel; }), idx);
     }
   },
   /**

packages/ember-data/lib/system/model/attributes.js

@@ -300,25 +300,27 @@ export default function attr(type, options) {
 
   return computedPolyfill({
     get: function(key) {
-      if (hasValue(this, key)) {
-        return getValue(this, key);
+      var internalModel = this._internalModel;
+      if (hasValue(internalModel, key)) {
+        return getValue(internalModel, key);
       } else {
         return getDefaultValue(this, options, key);
       }
     },
     set: function(key, value) {
       Ember.assert("You may not set `id` as an attribute on your model. Please remove any lines that look like: `id: DS.attr('<type>')` from " + this.constructor.toString(), key !== 'id');
-      var oldValue = getValue(this, key);
+      var internalModel = this._internalModel;
+      var oldValue = getValue(internalModel, key);
 
       if (value !== oldValue) {
         // Add the new value to the changed attributes hash; it will get deleted by
         // the 'didSetProperty' handler if it is no different from the original value
-        this._attributes[key] = value;
+        internalModel._attributes[key] = value;
 
-        this.send('didSetProperty', {
+        this._internalModel.send('didSetProperty', {
           name: key,
           oldValue: oldValue,
-          originalValue: this._data[key],
+          originalValue: internalModel._data[key],
           value: value
         });
       }