Disabling Rails sessions and airbrake gem
undefined method `data' for nil:NilClass
This is because airbrake read the
session.data property to send them to the server.
Since you disabled sessions, your controller’s session returns nil.
I submitted a fix to airbrake, if you can’t wait you can source your aibrake gem from my github repository
Edit : My branch has been merged in master, you can now rely on master.