Persistence#delete should not be affected by scoping

`self.class.delete` is delegated to `all` and `all` is affected by
scoping. It should use `unscoped` to not be affected by that.

activerecord/lib/active_record/persistence.rb

@@ -175,7 +175,7 @@ module ActiveRecord
     # callbacks or any <tt>:dependent</tt> association
     # options, use <tt>#destroy</tt>.
     def delete
-      self.class.delete(id) if persisted?
+      _relation_for_itself.delete_all if persisted?
       @destroyed = true
       freeze
     end
@@ -555,6 +555,10 @@ module ActiveRecord
     end
 
     def relation_for_destroy
+      _relation_for_itself
+    end
+
+    def _relation_for_itself
       self.class.unscoped.where(self.class.primary_key => id)
     end
 

activerecord/test/cases/persistence_test.rb

@@ -437,6 +437,13 @@ class PersistenceTest < ActiveRecord::TestCase
     assert_not_nil Topic.find(2)
   end
 
+  def test_delete_isnt_affected_by_scoping
+    topic = Topic.find(1)
+    assert_difference("Topic.count", -1) do
+      Topic.where("1=0").scoping { topic.delete }
+    end
+  end
+
   def test_destroy
     topic = Topic.find(1)
     assert_equal topic, topic.destroy, "topic.destroy did not return self"