Rails 2.2 Change: Private Methods on Association Proxies are Private

There's a small change in Active Record behavior that's going to bite some existing applications under Rails 2.2: private methods on an association proxy are actually private. To illustrate, this code would work in Rails 2.1:

user.rb:

[sourcecode language='ruby']
class User < ActiveRecord::Base
has_one :account
end
[/sourcecode]

account.rb:

[sourcecode language='ruby']
class Account < ActiveRecord::Base
belongs_to :user
private
def secret_code
"ABCDE"
end
end
[/sourcecode]

Controller code:

[sourcecode language='ruby']
@u = User.first
@code = u.account.secret_code
[/sourcecode]

With Rails 2.1, you'll actually get the secret code in @code, even though it comes from a private method of the account object. Rails 2.2 is stricter about this: that same code will fail with a NoMethodError. If you want to access a private method across an association proxy now, you'll need to use @code = u.account.send("secret_code").

Directly accessing private methods on an Active Record instance itself was already blocked in Rails 2.1, but Rails 2.2 updates that failure to give back a NoMethodError as well.