rails/rails — pull request #7080 by jfirebaugh (2012-07-17 21:04:16+00:00)
Title: AR::Integration must be included after AM::Conversion

Integration's definition of #to_param must override Conversion's. Otherwise,
there is a regression from 3.1 in the behavior of a non-persisted AR::Base
instance which nevertheless has an id.

On master, a similar change is needed -- or we can remove AR::Integration#to_param
and accept the behavioral change, or we can remove AR::Integration#to_param and
change AM::Conversion#to_param to have the AR::Integration behavior.