Active scopes apply to child classes, though not parents/siblings

While the commit message (and changelog example) in
5e0b555b talked about sibling classes,
the added test had a child ignore its parent's scoping, which seems less
reasonable.

activerecord/lib/active_record/scoping.rb

@@ -11,11 +11,11 @@ module Scoping
 
     module ClassMethods
       def current_scope #:nodoc:
-        ScopeRegistry.value_for(:current_scope, self.to_s)
+        ScopeRegistry.value_for(:current_scope, self)
       end
 
       def current_scope=(scope) #:nodoc:
-        ScopeRegistry.set_value_for(:current_scope, self.to_s, scope)
+        ScopeRegistry.set_value_for(:current_scope, self, scope)
       end
 
       # Collects attributes from scopes that should be applied when creating
@@ -53,18 +53,18 @@ def initialize_internals_callback # :nodoc:
     # following code:
     #
     #   registry = ActiveRecord::Scoping::ScopeRegistry
-    #   registry.set_value_for(:current_scope, "Board", some_new_scope)
+    #   registry.set_value_for(:current_scope, Board, some_new_scope)
     #
     # Now when you run:
     #
-    #   registry.value_for(:current_scope, "Board")
+    #   registry.value_for(:current_scope, Board)
     #
     # You will obtain whatever was defined in +some_new_scope+. The #value_for
     # and #set_value_for methods are delegated to the current ScopeRegistry
     # object, so the above example code can also be called as:
     #
     #   ActiveRecord::Scoping::ScopeRegistry.set_value_for(:current_scope,
-    #       "Board", some_new_scope)
+    #       Board, some_new_scope)
     class ScopeRegistry # :nodoc:
       extend ActiveSupport::PerThreadRegistry
 
@@ -74,16 +74,22 @@ def initialize
         @registry = Hash.new { |hash, key| hash[key] = {} }
       end
 
-      # Obtains the value for a given +scope_name+ and +variable_name+.
-      def value_for(scope_type, variable_name)
+      # Obtains the value for a given +scope_type+ and +model+.
+      def value_for(scope_type, model)
         raise_invalid_scope_type!(scope_type)
-        @registry[scope_type][variable_name]
+        klass = model
+        base = model.base_class
+        while klass <= base
+          value = @registry[scope_type][klass.name]
+          return value if value
+          klass = klass.superclass
+        end
       end
 
-      # Sets the +value+ for a given +scope_type+ and +variable_name+.
-      def set_value_for(scope_type, variable_name, value)
+      # Sets the +value+ for a given +scope_type+ and +model+.
+      def set_value_for(scope_type, model, value)
         raise_invalid_scope_type!(scope_type)
-        @registry[scope_type][variable_name] = value
+        @registry[scope_type][model.name] = value
       end
 
       private

activerecord/test/cases/base_test.rb

@@ -1275,9 +1275,10 @@ def test_current_scope_is_reset
     UnloadablePost.send(:current_scope=, UnloadablePost.all)
 
     UnloadablePost.unloadable
-    assert_not_nil ActiveRecord::Scoping::ScopeRegistry.value_for(:current_scope, "UnloadablePost")
+    klass = UnloadablePost
+    assert_not_nil ActiveRecord::Scoping::ScopeRegistry.value_for(:current_scope, klass)
     ActiveSupport::Dependencies.remove_unloadable_constants!
-    assert_nil ActiveRecord::Scoping::ScopeRegistry.value_for(:current_scope, "UnloadablePost")
+    assert_nil ActiveRecord::Scoping::ScopeRegistry.value_for(:current_scope, klass)
   ensure
     Object.class_eval{ remove_const :UnloadablePost } if defined?(UnloadablePost)
   end

activerecord/test/cases/scoping/relation_scoping_test.rb

@@ -209,9 +209,23 @@ def test_delete_all_default_scope_filters_on_joins
     assert_not_equal [], Developer.all
   end
 
-  def test_current_scope_does_not_pollute_other_subclasses
-    Post.none.scoping do
-      assert StiPost.all.any?
+  def test_current_scope_does_not_pollute_sibling_subclasses
+    Comment.none.scoping do
+      assert_not SpecialComment.all.any?
+      assert_not VerySpecialComment.all.any?
+      assert_not SubSpecialComment.all.any?
+    end
+
+    SpecialComment.none.scoping do
+      assert Comment.all.any?
+      assert VerySpecialComment.all.any?
+      assert_not SubSpecialComment.all.any?
+    end
+
+    SubSpecialComment.none.scoping do
+      assert Comment.all.any?
+      assert VerySpecialComment.all.any?
+      assert SpecialComment.all.any?
     end
   end
 end