Undefined method `rescue_responses' for ActionController::Base:Class in Rails Edge

Greetings. I just started a new rails project basing off the edge.[1] I prefer to unpack my gems, but when I did so, I received the error below. Anybody else encounter this and have a suggestion?

$ rake gems:unpack (in [omitted]) rake aborted! undefined method `rescue_responses' for ActionController::Base:Class

(See full trace by running task with --trace)

Thanks, Ben