Adam Milligan's blog
A while back I made the point that the HasOneThroughAssociation class in Rails shouldn't be a subclass of HasManyThroughAssociation. I also submitted a Rails patch in which I changed the superclass of HasOneThroughAssociation from HasManyThroughAssociation to HasOneAssociation and moved the shared Through functionality into a module. Despite support from the teeming millions, Rails core team member Pratik rejected the patch for being "just a refactoring."