Remove deprecated code concerning non-attributes and *_will_change!

activerecord/lib/active_record/attribute_methods/dirty.rb

@@ -209,17 +209,7 @@ module ActiveRecord
 
         def attribute_will_change!(attr_name)
           super
-          if self.class.has_attribute?(attr_name)
-            mutations_from_database.force_change(attr_name)
-          else
-            ActiveSupport::Deprecation.warn(<<-EOW.squish)
-              #{attr_name} is not an attribute known to Active Record.
-              This behavior is deprecated and will be removed in the next
-              version of Rails. If you'd like #{attr_name} to be managed
-              by Active Record, add `attribute :#{attr_name}` to your class.
-            EOW
-            mutations_from_database.deprecated_force_change(attr_name)
-          end
+          mutations_from_database.force_change(attr_name)
         end
 
         def _update_record(*)

activerecord/lib/active_record/attribute_mutation_tracker.rb

@@ -5,7 +5,6 @@ module ActiveRecord
     def initialize(attributes)
       @attributes = attributes
       @forced_changes = Set.new
-      @deprecated_forced_changes = Set.new
     end
 
     def changed_values
@@ -33,7 +32,7 @@ module ActiveRecord
     end
 
     def any_changes?
-      attr_names.any? { |attr| changed?(attr) } || deprecated_forced_changes.any?
+      attr_names.any? { |attr| changed?(attr) }
     end
 
     def changed?(attr_name, from: OPTION_NOT_GIVEN, to: OPTION_NOT_GIVEN)
@@ -62,15 +61,11 @@ module ActiveRecord
       forced_changes << attr_name.to_s
     end
 
-    def deprecated_force_change(attr_name)
-      deprecated_forced_changes << attr_name.to_s
-    end
-
     # TODO Change this to private once we've dropped Ruby 2.2 support.
     # Workaround for Ruby 2.2 "private attribute?" warning.
     protected
 
-      attr_reader :attributes, :forced_changes, :deprecated_forced_changes
+      attr_reader :attributes, :forced_changes
 
     private
 

activerecord/test/cases/dirty_test.rb

@@ -299,11 +299,9 @@ class DirtyTest < ActiveRecord::TestCase
   end
 
   def test_virtual_attribute_will_change
-    assert_deprecated do
-      parrot = Parrot.create!(name: "Ruby")
-      parrot.send(:attribute_will_change!, :cancel_save_from_callback)
-      assert parrot.has_changes_to_save?
-    end
+    parrot = Parrot.create!(name: "Ruby")
+    parrot.send(:attribute_will_change!, :cancel_save_from_callback)
+    assert parrot.has_changes_to_save?
   end
 
   def test_association_assignment_changes_foreign_key

activerecord/test/models/parrot.rb

@@ -8,7 +8,7 @@ class Parrot < ActiveRecord::Base
 
   validates_presence_of :name
 
-  attr_accessor :cancel_save_from_callback
+  attribute :cancel_save_from_callback
   before_save :cancel_save_callback_method, if: :cancel_save_from_callback
   def cancel_save_callback_method
     throw(:abort)