ActiveResource::create with an existing id: Rails 3.0 vs Rails 3.1 and above

I’m upgrading my application from Rails 3.0 to Rails 3.2 (yeah, I know,
what happened to 3.1?), and I’m experiencing a difference in the REST
call
when calling ActiveResource::create where the id is already defined. In
3.0, the app is sending a PUT. In 3.1 and above, is sending a POST.
The
PUT seemed to make sense to me since the id already exists.

Is there any documentation of this change? Am I experiencing something
strange?

Thanks in advance, Chuck

Well, when in doubt, check the source code. In 3.0, create checks new?
which looks to see if id.nil? In 3.1 and above, it also checks new?, but
now, new? checks to see if the object has been persisted (which is
different from checking to see if id is defined).