Adam Milligan's blog
How many times has this happened to you? You get a cool design for your website, and you spend a bunch of time lining up all of your images and roundy-corner widgets and input boxes just... so..., and everything looks great. But, then you submit a form without typing in your favorite ice cream (a required field, of course), and suddenly your layout is splattered about like an extra large scoop of rocky road in the hands of a two year old. It's enough to make you want to stab your eyes out with a hedge trimmer.
Rails has had the has_one :through association for a while now, and you probably use it on occasion. But, has it ever given you the heebie-jeebies a little bit? Maybe something happens now and then that doesn't seem quite right? Well, the reason for this is that HasOneThroughAssociation, the class that ActiveRecord uses (shockingly) to implement has_one :through associations, is a subclass of HasManyThroughAssociation.
Whhaaaaaaaaaat?
Yes, oddly enough, a has_one :through association is a collection that is special-cased to always return just one element. Seems kind of dirty, doesn't it?
A while back I wrote about private methods in ActiveRecord objects, and how Rails 2.2 makes them behave as they should. ActiveRecord associations will no longer respond to private methods defined on their targets; however, my colleague Joseph pointed out that they also no longer respond to methods defined via #method_missing on their targets. Which sucks horse poop through a straw, to some extent.