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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

Inherits From

Constants

DEFAULT_BEHAVIORS

Default warning behaviors per Rails.env.

{
raise: ->(message, callstack, deprecator) do
e = DeprecationException.new(message)
e.set_backtrace(callstack.map(&:to_s))
raise e
end,

stderr: ->(message, callstack, deprecator) do
$stderr.puts(message)
$stderr.puts callstack.join("\n  ") if deprecator.debug
end,

log: ->(message, callstack, deprecator) do
logger =
if defined?(Rails.logger) && Rails.logger
Rails.logger
else
require "active_support/logger"
ActiveSupport::Logger.new($stderr)
end
logger.warn message
logger.debug callstack.join("\n  ") if deprecator.debug
end,

notify: ->(message, callstack, deprecator) do
ActiveSupport::Notifications.instrument(
"deprecation.#{deprecator.gem_name.underscore.tr("/", "_")}",
message: message,
callstack: callstack,
gem_name: deprecator.gem_name,
deprecation_horizon: deprecator.deprecation_horizon,
)
end,

silence: ->(message, callstack, deprecator) { },

report: ->(message, callstack, deprecator) do
error = DeprecationException.new(message)
error.set_backtrace(callstack.map(&:to_s))
ActiveSupport.error_reporter.report(error)
end
}

Attributes

[RW] deprecation_horizon

The version number in which the deprecated behavior will be removed, by default.

Public class methods

new(deprecation_horizon = "8.2", gem_name = "Rails")

It accepts two parameters on initialization. The first is a version of library and the second is a library name.

ActiveSupport::Deprecation.new('2.0', 'MyLibrary')
Source code GitHub 
# File activesupport/lib/active_support/deprecation.rb, line 71
def initialize(deprecation_horizon = "8.2", 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

Namespace

Definition files