Define a convention for descendants and subclasses.

The former should be symmetric with ancestors and include all children. However, it should not include self since ancestors + descendants should not have duplicated. The latter is symmetric to superclass in the sense it only includes direct children.

By adopting a convention, we expect to have less conflict with other frameworks, as Datamapper. For this moment, to ensure ActiveModel::Validations can be used with Datamapper, we should always call ActiveSupport::DescendantsTracker.descendants(self) internally instead of self.descendants avoiding conflicts.

1 files changed, 5 insertions, 3 deletions

diff --git a/activesupport/test/descendants_tracker_test.rb b/activesupport/test/descendants_tracker_test.rb
index ff24e310de..79fb893592 100644
--- a/activesupport/test/descendants_tracker_test.rb
+++ b/activesupport/test/descendants_tracker_test.rb
@@ -37,7 +37,9 @@ class DescendantsTrackerTest < Test::Unit::TestCase
   def test_clear_with_autoloaded_parent_children_and_granchildren
     mark_as_autoloaded(*ALL) do
       ActiveSupport::DescendantsTracker.clear
-      assert ActiveSupport::DescendantsTracker.descendants.slice(*ALL).empty?
+      ALL.each do |k|
+        assert ActiveSupport::DescendantsTracker.descendants(k).empty?
+      end
     end
   end
 
@@ -64,12 +66,12 @@ class DescendantsTrackerTest < Test::Unit::TestCase
     old_autoloaded = ActiveSupport::Dependencies.autoloaded_constants.dup
     ActiveSupport::Dependencies.autoloaded_constants = klasses.map(&:name)
 
-    old_descendants = ActiveSupport::DescendantsTracker.descendants.dup
+    old_descendants = ActiveSupport::DescendantsTracker.class_eval("@@direct_descendants").dup
     old_descendants.each { |k, v| old_descendants[k] = v.dup }
 
     yield
   ensure
     ActiveSupport::Dependencies.autoloaded_constants = old_autoloaded
-    ActiveSupport::DescendantsTracker.descendants.replace(old_descendants)
+    ActiveSupport::DescendantsTracker.class_eval("@@direct_descendants").replace(old_descendants)
   end
 end
\ No newline at end of file