Performance: faster Object.subclasses_of

1 files changed, 9 insertions, 8 deletions

diff --git a/activesupport/lib/active_support/core_ext/object/extending.rb b/activesupport/lib/active_support/core_ext/object/extending.rb
index 43a2be916e..082e98a297 100644
--- a/activesupport/lib/active_support/core_ext/object/extending.rb
+++ b/activesupport/lib/active_support/core_ext/object/extending.rb
@@ -3,17 +3,18 @@ class Object
     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 = []
 
-    # 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.
-    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
+    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