If set() includes an id, the id gets set as an attribute of the model.

[HenrikJoreteg]

The title says it all. This is also a problem because it can incorrectly trigger a 'change' event.

[jashkenas]

This is how it's supposed to behave. You're notified when a model you're observing changes id, and can even listen for "change:id" events. Having the id be treated specially and being set as a direct property of the model object is a convenience:

http://documentcloud.github.com/backbone/#Model-id

Is there a particular reason you think it should behave differently?

[HenrikJoreteg]

So, after looking into it more, that's not the problem. I have no problem with id behaving that way. When I got an unexpected change event and then saw the id listed in attributes I assumed it was a mistake. But, I just hadn't noticed before.

The real problem is that this test fails:

test("Model: change event bug", function () {
  var changed = 0;
  var attrs = {id: 1, label: 'c'};
  var obj = new Backbone.Model(attrs);
  obj.bind('change', function() { changed += 1; });
  obj.set(attrs);
  equals(changed, 0);
});

Nothing should have changed — yet, I got a change event. Also, if inside the change callback you call changedAttributes() you get false.

This sure seems like a bug, no?

[jashkenas]

It sure is -- thanks for reporting this. Here's the patch with a fix:

53ae5b5