make ActiveRecord::Base.subclasses a public method

Signed-off-by: wycats <wycats@gmail.com>

activerecord/lib/active_record/base.rb

@@ -1285,11 +1285,15 @@ module ActiveRecord #:nodoc:
           with_scope(method_scoping, :overwrite, &block)
         end
 
-        def subclasses #:nodoc:
+        # ActiveRecord::Base utilizes the inherited hook to know about new subclasses.
+        # You can access the list of currently loaded ActiveRecord::Base subclasses using this accessor.
+        def subclasses
           @@subclasses[self] ||= []
           @@subclasses[self] + extra = @@subclasses[self].inject([]) {|list, subclass| list + subclass.subclasses }
         end
 
+        public :subclasses
+
         # Sets the default options for the model. The format of the
         # <tt>options</tt> argument is the same as in find.
         #

activerecord/test/cases/base_test.rb

@@ -2053,6 +2053,10 @@ class BasicsTest < ActiveRecord::TestCase
     assert !SubStiPost.descends_from_active_record?
   end
 
+  def test_base_subclasses_is_public_method
+    assert ActiveRecord::Base.public_methods.include?("subclasses")
+  end
+
   def test_find_on_abstract_base_class_doesnt_use_type_condition
     old_class = LooseDescendant
     Object.send :remove_const, :LooseDescendant