Methods in included block

Development
#1

Hi fellow Rubyists,

I saw methods defined directly in included block when using Concern
several times.

module AModule
extend ActiveSupport::Concern

included do
# this is BAD
def a_method
end
end
end

It is a bad practice and it breaks things, all instance methods should
go to the AModule, and all class methods to a ClassMethods module.

  • It dynamically creates methods in each class, they are not shared
    through module, it is slow.
  • It cannot be accessed for extension, there is no module to include to.
  • it breaks super calls.

We should avoid using this and go for:

module AModule
extend ActiveSupport::Concern

included do
# e.g.
has_one :user
end

module ClassMethods
def a_method
end
end
end

Thanks.

I'll create issue to remove these bad definitions.

Petr