Counterintuitive behavior in ActiveRecord I was implementing dirty checking for an application, and I found something that is a little counterintuitive. Let me start with a quick quiz: bob=User.find(1) alice=User.find(2) trip=Trip.new trip.driver=bob

I was implementing dirty checking for an application, and I found something that is a little counterintuitive. Let me start with a quick quiz:

bob=User.find(1)
alice=User.find(2)
trip=Trip.new

trip.driver=bob
old_driver=trip.driver
trip.driver=alice

In this example, who is old_driver? If you guessed Alice, you're right.

Inside associations.rb, the mutator is defined as:
           define_method("#{reflection.name}=") do |new_value|
             association = instance_variable_get("@#{reflection.name}")
             if association.nil?
               association = association_proxy_class.new(self, reflection)
             end

             association.replace(new_value)

By re-using the proxy, we get this odd assignment behavior. Is there any reason not to create a new proxy on assignment?

Simply eliminating the if condition fixes my case, and all tests still pass.

I can create a ticket with tests and a patch if I'm not missing something here.

Mike
http://www.elevatedrails.com