Extract descendents a bit so it can take advantage of Rubinius' __sub…

…classes__.

activesupport/lib/active_support/core_ext/class/removal.rb

@@ -2,7 +2,11 @@
 require 'active_support/core_ext/module/introspection'
 
 class Class #:nodoc:
-
+
+  def reachable?
+    eval("defined?(::#{self}) && ::#{self}.equal?(self)")
+  end
+
   # Unassociates the class with its subclasses and removes the subclasses
   # themselves.
   #

activesupport/lib/active_support/core_ext/object/extending.rb

@@ -1,46 +1,53 @@
-class Object
-  def remove_subclasses_of(*superclasses) #:nodoc:
-    Class.remove_class(*subclasses_of(*superclasses))
-  end
-
-  begin
-    ObjectSpace.each_object(Class.new) {}
-
-    # Exclude this class unless it's a subclass of our supers and is defined.
-    # We check defined? in case we find a removed class that has yet to be
-    # garbage collected. This also fails for anonymous classes -- please
-    # submit a patch if you have a workaround.
-    def subclasses_of(*superclasses) #:nodoc:
+class Class
+  # Rubinius
+  if defined?(Class.__subclasses__)
+    def descendents
       subclasses = []
-
-      superclasses.each do |sup|
-        ObjectSpace.each_object(class << sup; self; end) do |k|
-          if k != sup && (k.name.blank? || eval("defined?(::#{k}) && ::#{k}.object_id == k.object_id"))
-            subclasses << k
-          end
-        end
-      end
-
+      __subclasses__.each {|k| subclasses << k; subclasses.concat k.descendents }
       subclasses
     end
-  rescue RuntimeError
-    # JRuby and any implementations which cannot handle the objectspace traversal
-    # above fall back to this implementation
-    def subclasses_of(*superclasses) #:nodoc:
-      subclasses = []
+  else
+    # MRI
+    begin
+      ObjectSpace.each_object(Class.new) {}
 
-      superclasses.each do |sup|
+      def descendents
+        subclasses = []
+        ObjectSpace.each_object(class << self; self; end) do |k|
+          subclasses << k unless k == self
+        end
+        subclasses
+      end
+    # JRuby
+    rescue StandardError
+      def descendents
+        subclasses = []
         ObjectSpace.each_object(Class) do |k|
-          if superclasses.any? { |superclass| k < superclass } &&
-            (k.name.blank? || eval("defined?(::#{k}) && ::#{k}.object_id == k.object_id"))
-            subclasses << k
-          end
+          subclasses << k if k < self
         end
         subclasses.uniq!
+        subclasses
       end
-      subclasses
     end
   end
+end
+
+class Object
+  def remove_subclasses_of(*superclasses) #:nodoc:
+    Class.remove_class(*subclasses_of(*superclasses))
+  end
+
+  # Exclude this class unless it's a subclass of our supers and is defined.
+  # We check defined? in case we find a removed class that has yet to be
+  # garbage collected. This also fails for anonymous classes -- please
+  # submit a patch if you have a workaround.
+  def subclasses_of(*superclasses) #:nodoc:
+    subclasses = []
+    superclasses.each do |klass|
+      subclasses.concat klass.descendents.select {|k| k.name.blank? || k.reachable?}
+    end
+    subclasses
+  end
 
   def extended_by #:nodoc:
     ancestors = class << self; ancestors end