class ActiveSupport::Deprecation

Active Support Deprecation

Deprecation specifies the API used by Rails to deprecate methods, instance variables, objects, and constants. It’s also available for gems or applications.

For a gem, use Deprecation.new to create a Deprecation object and store it in your module or class (in order for users to be able to configure it).

module MyLibrary
  def self.deprecator
    @deprecator ||= ActiveSupport::Deprecation.new("2.0", "MyLibrary")
  end
end

For a Railtie or Engine, you may also want to add it to the application’s deprecators, so that the application’s configuration can be applied to it.

module MyLibrary
  class Railtie < Rails::Railtie
    initializer "my_library.deprecator" do |app|
      app.deprecators[:my_library] = MyLibrary.deprecator
    end
  end
end

With the above initializer, configuration settings like the following will affect MyLibrary.deprecator:

# in config/environments/test.rb
config.active_support.deprecation = :raise