Merge pull request rails#52720 from rails/revert-52717-class-attribute-redefine-once

Revert "class_attribute: reduce reliance on define_method"

Author: byroot

activerecord/test/cases/test_case.rb

@@ -141,6 +141,9 @@ def with_has_many_inversing(model = ActiveRecord::Base)
       yield
     ensure
       model.has_many_inversing = old
+      if model != ActiveRecord::Base && !old
+        model.singleton_class.remove_method(:has_many_inversing) # reset the class_attribute
+      end
     end
 
     def with_automatic_scope_inversing(*reflections)

activesupport/lib/active_support.rb

@@ -62,7 +62,6 @@ module ActiveSupport
     autoload :Cache
     autoload :Callbacks
     autoload :Configurable
-    autoload :ClassAttribute
     autoload :Deprecation
     autoload :Delegation
     autoload :Digest

activesupport/lib/active_support/callbacks.rb

@@ -66,7 +66,7 @@ module Callbacks
 
     included do
       extend ActiveSupport::DescendantsTracker
-      class_attribute :__callbacks, instance_writer: false, instance_predicate: false, default: {}
+      class_attribute :__callbacks, instance_writer: false, default: {}
     end
 
     CALLBACK_FILTER_TYPES = [:before, :after, :around].freeze

activesupport/lib/active_support/class_attribute.rb

@@ -91,16 +91,24 @@ def class_attribute(*attrs, instance_accessor: true,
         raise TypeError, "#{name.inspect} is not a symbol nor a string"
       end
 
-      name = name.to_sym
-      ::ActiveSupport::ClassAttribute.redefine(self, name, default)
+      class_methods << <<~RUBY # In case the method exists and is not public
+        silence_redefinition_of_method def #{name}
+        end
+      RUBY
 
-      unless singleton_class?
-        methods << <<~RUBY if instance_reader
-          silence_redefinition_of_method def #{name}
-            defined?(@#{name}) ? @#{name} : self.class.#{name}
-          end
-        RUBY
-      end
+      methods << <<~RUBY if instance_reader
+        silence_redefinition_of_method def #{name}
+          defined?(@#{name}) ? @#{name} : self.class.#{name}
+        end
+      RUBY
+
+      class_methods << <<~RUBY
+        silence_redefinition_of_method def #{name}=(value)
+          redefine_method(:#{name}) { value } if singleton_class?
+          redefine_singleton_method(:#{name}) { value }
+          value
+        end
+      RUBY
 
       methods << <<~RUBY if instance_writer
         silence_redefinition_of_method(:#{name}=)
@@ -117,5 +125,7 @@ def class_attribute(*attrs, instance_accessor: true,
 
     location = caller_locations(1, 1).first
     class_eval(["class << self", *class_methods, "end", *methods].join(";").tr("\n", ";"), location.path, location.lineno)
+
+    attrs.each { |name| public_send("#{name}=", default) }
   end
 end

activesupport/lib/active_support/core_ext/class/attribute.rb

@@ -30,14 +30,11 @@ def setup
   test "overridable" do
     @sub.setting = 1
     assert_nil @klass.setting
-    assert_equal 1, @sub.setting
 
     @klass.setting = 2
-    assert_equal 2, @klass.setting
     assert_equal 1, @sub.setting
 
     assert_equal 1, Class.new(@sub).setting
-    assert_equal 2, Class.new(@klass).setting
   end
 
   test "predicate method" do
@@ -100,34 +97,8 @@ def setup
 
   test "works well with singleton classes" do
     object = @klass.new
-
     object.singleton_class.setting = "foo"
     assert_equal "foo", object.setting
-    assert_nil @klass.setting
-
-    object.singleton_class.setting = "bar"
-    assert_equal "bar", object.setting
-    assert_nil @klass.setting
-
-    @klass.setting = "plop"
-    assert_equal "bar", object.setting
-    assert_equal "plop", @klass.setting
-  end
-
-  test "when defined in a class's singleton" do
-    @klass = Class.new do
-      class << self
-        class_attribute :__callbacks, default: 1
-      end
-    end
-
-    assert_equal 1, @klass.__callbacks
-    assert_equal 1, @klass.singleton_class.__callbacks
-
-    # I honestly think this is a bug, but that's how it used to behave
-    @klass.__callbacks = 4
-    assert_equal 1, @klass.__callbacks
-    assert_equal 1, @klass.singleton_class.__callbacks
   end
 
   test "works well with module singleton classes" do