js/libs/ember-data.js
function(data) {
    set(this, 'isError', false);

    if (data) {
      this._data = data;
    } else {
      Ember.mixin(this._data, this._inFlightAttributes);
    }

    this._inFlightAttributes = {};

    this.send('didCommit');
    this.updateRecordArraysLater();

    if (!data) { return; }

    this.suspendRelationshipObservers(function() {
      this.notifyPropertyChange('data');
    });
  }
function(data) {
    set(this, 'isError', false);

    if (data) {
      this._data = data;
    } else {
      Ember.mixin(this._data, this._inFlightAttributes);
    }

    this._inFlightAttributes = {};

    this.send('didCommit');
    this.updateRecordArraysLater();

    if (!data) { return; }

    this.suspendRelationshipObservers(function() {
      this.notifyPropertyChange('data');
    });
  }
If the adapter did not return a hash in response to a commit,
merge the changed attributes and relationships into the existing
saved data.

@method adapterDidCommit