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

ActiveSupport::Deprecation.new('2.0', 'MyLibrary')

# File activesupport/lib/active_support/deprecation.rb, line 71
def initialize(deprecation_horizon = "8.1", gem_name = "Rails")
  self.gem_name = gem_name
  self.deprecation_horizon = deprecation_horizon
  # By default, warnings are not silenced and debugging is off.
  self.silenced = false
  self.debug = false
  @silence_counter = Concurrent::ThreadLocalVar.new(0)
  @explicitly_allowed_warnings = Concurrent::ThreadLocalVar.new(nil)
end