Merge pull request #10113 from Agis-/default_scopes_predicate

Deprecate ActiveRecord#Base.default_scopes?

Closes #10107

6 files changed, 35 insertions, 6 deletions

diff --git a/activerecord/CHANGELOG.md b/activerecord/CHANGELOG.md
index 0ab01d6183..5891de9841 100644
--- a/activerecord/CHANGELOG.md
+++ b/activerecord/CHANGELOG.md
@@ -1,5 +1,10 @@
 ## Rails 4.0.0 (unreleased) ##
 
+*   `#default_scopes?` is deprecated. Instead, do something like
+    `Post.default_scopes.empty?`.
+
+    *Agis Anastasopoulos*
+
 *   Default values for PostgreSQL bigint types now get parsed and dumped to the
     schema correctly.
 
diff --git a/activerecord/lib/active_record/scoping/default.rb b/activerecord/lib/active_record/scoping/default.rb
index cde4f29d08..8a90528ce8 100644
--- a/activerecord/lib/active_record/scoping/default.rb
+++ b/activerecord/lib/active_record/scoping/default.rb
@@ -5,8 +5,17 @@ module ActiveRecord
 
       included do
         # Stores the default scope for the class.
-        class_attribute :default_scopes, instance_writer: false
+        class_attribute :default_scopes, instance_writer: false, instance_predicate: false
+
         self.default_scopes = []
+
+        def self.default_scopes?
+          ActiveSupport::Deprecation.warn(
+            "#default_scopes? is deprecated. Do something like #default_scopes.empty? instead."
+          )
+
+          !!self.default_scopes
+        end
       end
 
       module ClassMethods
diff --git a/activesupport/CHANGELOG.md b/activesupport/CHANGELOG.md
index 3e2967f57d..fcb6b09e77 100644
--- a/activesupport/CHANGELOG.md
+++ b/activesupport/CHANGELOG.md
@@ -1,5 +1,11 @@
 ## Rails 4.0.0 (unreleased) ##
 
+*   `Class#class_attribute` accepts an `instance_predicate` option which
+    defaults to `true`. If set to `false` the predicate method will not
+    be defined.
+
+    *Agis Anastasopoulos*
+
 *   `fast_xs` support has been removed.  Use 'String#encode(xml: :attr)`.
 
 *   `ActiveSupport::Notifications::Instrumenter#instrument` should yield
diff --git a/activesupport/lib/active_support/core_ext/class/attribute.rb b/activesupport/lib/active_support/core_ext/class/attribute.rb
index e51ab9ddbc..6d49b7b6e1 100644
--- a/activesupport/lib/active_support/core_ext/class/attribute.rb
+++ b/activesupport/lib/active_support/core_ext/class/attribute.rb
@@ -44,7 +44,8 @@ class Class
   #   Base.setting               # => []
   #   Subclass.setting           # => [:foo]
   #
-  # For convenience, a query method is defined as well:
+  # For convenience, an instance predicate method is defined as well.
+  # To skip it, pass <tt>instance_predicate: false</tt>.
   #
   #   Subclass.setting?       # => false
   #
@@ -72,10 +73,11 @@ class Class
     # double assignment is used to avoid "assigned but unused variable" warning
     instance_reader = instance_reader = options.fetch(:instance_accessor, true) && options.fetch(:instance_reader, true)
     instance_writer = options.fetch(:instance_accessor, true) && options.fetch(:instance_writer, true)
+    instance_predicate = options.fetch(:instance_predicate, true)
 
     attrs.each do |name|
       define_singleton_method(name) { nil }
-      define_singleton_method("#{name}?") { !!public_send(name) }
+      define_singleton_method("#{name}?") { !!public_send(name) } if instance_predicate
 
       ivar = "@#{name}"
 
@@ -109,7 +111,7 @@ class Class
             self.class.public_send name
           end
         end
-        define_method("#{name}?") { !!public_send(name) }
+        define_method("#{name}?") { !!public_send(name) } if instance_predicate
       end
 
       attr_writer name if instance_writer
diff --git a/activesupport/test/core_ext/class/attribute_test.rb b/activesupport/test/core_ext/class/attribute_test.rb
index 1c3ba8a7a0..e7a1334db3 100644
--- a/activesupport/test/core_ext/class/attribute_test.rb
+++ b/activesupport/test/core_ext/class/attribute_test.rb
@@ -27,7 +27,7 @@ class ClassAttributeTest < ActiveSupport::TestCase
     assert_equal 1, Class.new(@sub).setting
   end
 
-  test 'query method' do
+  test 'predicate method' do
     assert_equal false, @klass.setting?
     @klass.setting = 1
     assert_equal true, @klass.setting?
@@ -48,7 +48,7 @@ class ClassAttributeTest < ActiveSupport::TestCase
     assert_equal 1, object.setting
   end
 
-  test 'instance query' do
+  test 'instance predicate' do
     object = @klass.new
     assert_equal false, object.setting?
     object.setting = 1
@@ -73,6 +73,11 @@ class ClassAttributeTest < ActiveSupport::TestCase
     assert_raise(NoMethodError) { object.setting = 'boom' }
   end
 
+  test 'disabling instance predicate' do
+    object = Class.new { class_attribute :setting, instance_predicate: false }.new
+    assert_raise(NoMethodError) { object.setting? }
+  end
+
   test 'works well with singleton classes' do
     object = @klass.new
     object.singleton_class.setting = 'foo'
diff --git a/guides/source/active_support_core_extensions.md b/guides/source/active_support_core_extensions.md
index 43529e3e96..101a4f5b42 100644
--- a/guides/source/active_support_core_extensions.md
+++ b/guides/source/active_support_core_extensions.md
@@ -1039,6 +1039,8 @@ For convenience `class_attribute` also defines an instance predicate which is th
 
 When `:instance_reader` is `false`, the instance predicate returns a `NoMethodError` just like the reader method.
 
+If you do not want the instance predicate,  pass `instance_predicate: false` and it will not be defined.
+
 NOTE: Defined in `active_support/core_ext/class/attribute.rb`
 
 #### `cattr_reader`, `cattr_writer`, and `cattr_accessor`