DeprecatedConstantProxy transforms a constant into a deprecated one. It takes the full names of an old (deprecated) constant and of a new constant (both in string form) and a deprecator. The deprecated constant now returns the value of the new one.

PLANETS = %w(mercury venus earth mars jupiter saturn uranus neptune pluto)

# (In a later update, the original implementation of `PLANETS` has been removed.)

PLANETS_POST_2006 = %w(mercury venus earth mars jupiter saturn uranus neptune)
PLANETS = ActiveSupport::Deprecation::DeprecatedConstantProxy.new("PLANETS", "PLANETS_POST_2006", ActiveSupport::Deprecation.new)

PLANETS.map { |planet| planet.capitalize }
# => DEPRECATION WARNING: PLANETS is deprecated! Use PLANETS_POST_2006 instead.
     (Backtrace information…)
     ["Mercury", "Venus", "Earth", "Mars", "Jupiter", "Saturn", "Uranus", "Neptune"]

Methods

Class Public methods

new(*args, **options, &block)

πŸ“ Source code 
# File activesupport/lib/active_support/deprecation/proxy_wrappers.rb, line 123
      def self.new(*args, **options, &block)
        object = args.first

        return object unless object
        super
      end
πŸ”Ž See on GitHub

new(old_const, new_const, deprecator = nil, message: "#{old_const} is deprecated! Use #{new_const} instead.")

πŸ“ Source code 
# File activesupport/lib/active_support/deprecation/proxy_wrappers.rb, line 130
      def initialize(old_const, new_const, deprecator = nil, message: "#{old_const} is deprecated! Use #{new_const} instead.")
        Kernel.require "active_support/inflector/methods"

        @old_const = old_const
        @new_const = new_const
        ActiveSupport.deprecator.warn("DeprecatedConstantProxy without a deprecator is deprecated") unless deprecator
        @deprecator = deprecator || ActiveSupport::Deprecation._instance
        @message = message
      end
πŸ”Ž See on GitHub

Instance Public methods

append_features(base)

πŸ“ Source code 
# File activesupport/lib/active_support/deprecation/proxy_wrappers.rb, line 161
      def append_features(base)
        @deprecator.warn(@message, caller_locations)
        base.include(target)
      end
πŸ”Ž See on GitHub

class()

Returns the class of the new constant.

PLANETS_POST_2006 = %w(mercury venus earth mars jupiter saturn uranus neptune)
PLANETS = ActiveSupport::Deprecation::DeprecatedConstantProxy.new('PLANETS', 'PLANETS_POST_2006')
PLANETS.class # => Array
πŸ“ Source code 
# File activesupport/lib/active_support/deprecation/proxy_wrappers.rb, line 157
      def class
        target.class
      end
πŸ”Ž See on GitHub

extended(base)

πŸ“ Source code 
# File activesupport/lib/active_support/deprecation/proxy_wrappers.rb, line 171
      def extended(base)
        @deprecator.warn(@message, caller_locations)
        base.extend(target)
      end
πŸ”Ž See on GitHub

inspect()

Don’t give a deprecation warning on inspect since test/unit and error logs rely on it for diagnostics.

πŸ“ Source code 
# File activesupport/lib/active_support/deprecation/proxy_wrappers.rb, line 144
      def inspect
        target.inspect
      end
πŸ”Ž See on GitHub

prepend_features(base)

πŸ“ Source code 
# File activesupport/lib/active_support/deprecation/proxy_wrappers.rb, line 166
      def prepend_features(base)
        @deprecator.warn(@message, caller_locations)
        base.prepend(target)
      end
πŸ”Ž See on GitHub