Deprecate Spree::Deprecation in favor of Spree.deprecator

Use autoload to print a deprecation only if the constant is loaded.

.rubocop.yml

@@ -337,7 +337,7 @@ Lint/SuppressedException:
 
 Lint/MissingSuper:
   Exclude:
-    - 'core/lib/spree/deprecation.rb' # this is a known class that doesn't require super
+    - 'core/lib/spree/deprecated_instance_variable_proxy.rb' # this is a known class that doesn't require super
     - 'core/lib/spree/preferences/configuration.rb' # this class has no superclass defining `self.inherited`
 
 Rails/FindEach:

core/lib/spree/core.rb

@@ -9,6 +9,8 @@
 require "active_storage/engine"
 require "sprockets/railtie"
 
+require 'active_support/deprecation'
+require 'spree/deprecated_instance_variable_proxy'
 require 'acts_as_list'
 require 'awesome_nested_set'
 require 'cancan'
@@ -19,13 +21,17 @@
 require 'ransack'
 require 'state_machines-activerecord'
 
-require 'spree/deprecation'
-
 # This is required because ActiveModel::Validations#invalid? conflicts with the
 # invalid state of a Payment. In the future this should be removed.
 StateMachines::Machine.ignore_method_conflicts = true
 
 module Spree
+  def self.deprecator
+    @deprecator ||= ActiveSupport::Deprecation.new('5.0', 'Solidus')
+  end
+
+  autoload :Deprecation, 'spree/deprecation'
+
   mattr_accessor :user_class, default: 'Spree::LegacyUser'
 
   def self.user_class

core/lib/spree/deprecated_instance_variable_proxy.rb

@@ -0,0 +1,57 @@
+# frozen_string_literal: true
+
+require 'active_support/deprecation'
+
+module Spree
+  # This DeprecatedInstanceVariableProxy transforms instance variable to
+  # deprecated instance variable.
+  #
+  # It differs from ActiveSupport::DeprecatedInstanceVariableProxy since
+  # it allows to define a custom message.
+  #
+  #   class Example
+  #     def initialize(deprecator)
+  #       @request = Spree::DeprecatedInstanceVariableProxy.new(self, :request, :@request, deprecator, "Please, do not use this thing.")
+  #       @_request = :a_request
+  #     end
+  #
+  #     def request
+  #       @_request
+  #     end
+  #
+  #     def old_request
+  #       @request
+  #     end
+  #   end
+  #
+  # When someone execute any method on @request variable this will trigger
+  # +warn+ method on +deprecator_instance+ and will fetch <tt>@_request</tt>
+  # variable via +request+ method and execute the same method on non-proxy
+  # instance variable.
+  #
+  # Default deprecator is <tt>Spree.deprecator</tt>.
+  class DeprecatedInstanceVariableProxy < ActiveSupport::Deprecation::DeprecationProxy
+    def initialize(instance, method_or_var, var = "@#{method}", deprecator = Spree.deprecator, message = nil)
+      @instance = instance
+      @method_or_var = method_or_var
+      @var = var
+      @deprecator = deprecator
+      @message = message
+    end
+
+    private
+
+    def target
+      return @instance.instance_variable_get(@method_or_var) if @instance.instance_variable_defined?(@method_or_var)
+
+      @instance.__send__(@method_or_var)
+    end
+
+    def warn(callstack, called, args)
+      message = @message || "#{@var} is deprecated! Call #{@method_or_var}.#{called} instead of #{@var}.#{called}."
+      message = [message, "Args: #{args.inspect}"].join(" ") unless args.empty?
+
+      @deprecator.warn(message, callstack)
+    end
+  end
+end

core/lib/spree/deprecation.rb

@@ -1,63 +1,9 @@
 # frozen_string_literal: true
 
-require 'active_support/deprecation'
+require 'spree/core'
 
 module Spree
-  def self.deprecator
-    @deprecator ||= ActiveSupport::Deprecation.new('5.0', 'Solidus')
-  end
-
   Deprecation = Spree.deprecator
 
-  # This DeprecatedInstanceVariableProxy transforms instance variable to
-  # deprecated instance variable.
-  #
-  # It differs from ActiveSupport::DeprecatedInstanceVariableProxy since
-  # it allows to define a custom message.
-  #
-  #   class Example
-  #     def initialize(deprecator)
-  #       @request = Spree::DeprecatedInstanceVariableProxy.new(self, :request, :@request, deprecator, "Please, do not use this thing.")
-  #       @_request = :a_request
-  #     end
-  #
-  #     def request
-  #       @_request
-  #     end
-  #
-  #     def old_request
-  #       @request
-  #     end
-  #   end
-  #
-  # When someone execute any method on @request variable this will trigger
-  # +warn+ method on +deprecator_instance+ and will fetch <tt>@_request</tt>
-  # variable via +request+ method and execute the same method on non-proxy
-  # instance variable.
-  #
-  # Default deprecator is <tt>Spree.deprecator</tt>.
-  class DeprecatedInstanceVariableProxy < ActiveSupport::Deprecation::DeprecationProxy
-    def initialize(instance, method_or_var, var = "@#{method}", deprecator = Spree.deprecator, message = nil)
-      @instance = instance
-      @method_or_var = method_or_var
-      @var = var
-      @deprecator = deprecator
-      @message = message
-    end
-
-    private
-
-    def target
-      return @instance.instance_variable_get(@method_or_var) if @instance.instance_variable_defined?(@method_or_var)
-
-      @instance.__send__(@method_or_var)
-    end
-
-    def warn(callstack, called, args)
-      message = @message || "#{@var} is deprecated! Call #{@method_or_var}.#{called} instead of #{@var}.#{called}."
-      message = [message, "Args: #{args.inspect}"].join(" ") unless args.empty?
-
-      @deprecator.warn(message, callstack)
-    end
-  end
+  Spree.deprecator.warn "Spree::Deprecation is deprecated. Please use Spree.deprecator instead.", caller(2)
 end

core/lib/spree/preferences/preferable_class_methods.rb

@@ -1,6 +1,5 @@
 # frozen_string_literal: true
 
-require 'spree/deprecation'
 require 'spree/encryptor'
 
 module Spree::Preferences