According to this, instance callback instance were deprecated, starting in Rails 2.3.8. An instance callback method is like this:
class Item < ActiveRecord::Base
def before_create
# whatever
end
end
By ActiveRecord 3.1.3 (used in Padrino 0.10.5), instance callback method support is gone. The supported way to do the above is:
class Item < ActiveRecord::Base
before_create :set_defaults
def set_defaults
# whatever
end
end
ActiveRecord (AR) had two or more incompatible ways to specify callbacks: instance methods (1st example) and callback queues (2nd example). If you have inherited AR classes (e.g. AdminUser is a child class of User, which is an AR) the instance method of the parent class is overridden and never called from child class instances. With callback queues, all callbacks are called. Current practice is described in ActiveRecord::Callbacks
In the Rails version of AmethystRSS.net, I'm using Rails 2.3.14 with instance callback methods, but not seeing any deprecation warnings. Not sure why.