4 files changed, 40 insertions, 12 deletions
diff --git a/activesupport/CHANGELOG b/activesupport/CHANGELOG
index b72d2fd5ed..0afb5f62b1 100644
--- a/activesupport/CHANGELOG
+++ b/activesupport/CHANGELOG
@@ -1,6 +1,6 @@
 *SVN*
 
-* Remove fix against memory leaks in development mode as it killed development performance on large applications (2-3s stall on Basecamp). Octopod is working on a better fix.
+* Added more efficient implementation of the development mode reset of classes #1638 [Chris McGrath]
 
 
 *1.1.0*
diff --git a/activesupport/lib/active_support/core_ext/object_and_class.rb b/activesupport/lib/active_support/core_ext/object_and_class.rb
index bd67b3d1fa..4ad13265d7 100644
--- a/activesupport/lib/active_support/core_ext/object_and_class.rb
+++ b/activesupport/lib/active_support/core_ext/object_and_class.rb
@@ -1,9 +1,9 @@
 class Object #:nodoc:
-  def remove_subclasses_of(superclass)
-    subclasses_of(superclass).each do |subclass|
-      # remove_instance_variables_of(klass)
-      Object.send(:remove_const, subclass) rescue nil
-    end 
+  def remove_subclasses_of(*superclasses)
+    subclasses_of(*superclasses).each do |subclass|
+      subclass.instance_variables.each { |v| subclass.send(:remove_instance_variable, v) }
+      Object.send(:remove_const, subclass.to_s) rescue nil
+    end
   end
   
   def remove_instance_variables_of(klass)
@@ -14,11 +14,11 @@ class Object #:nodoc:
     end   
   end
 
-  def subclasses_of(superclass)
+  def subclasses_of(*superclasses)
     subclasses = []
     ObjectSpace.each_object(Class) do |k|
-      next if !k.ancestors.include?(superclass) || superclass == k || k.to_s.include?("::") || subclasses.include?(k.to_s)
-      subclasses << k.to_s
+      next if (k.ancestors & superclasses).empty? || superclasses.include?(k) || k.to_s.include?("::") || subclasses.include?(k)
+      subclasses << k
     end
     subclasses
   end
@@ -50,6 +50,6 @@ class Class #:nodoc:
   end
 
   def subclasses
-    Object.subclasses_of(self)
+    Object.subclasses_of(self).map { |o| o.to_s }
   end
 end
diff --git a/activesupport/lib/active_support/dependencies.rb b/activesupport/lib/active_support/dependencies.rb
index bb46087582..c37e868b83 100644
--- a/activesupport/lib/active_support/dependencies.rb
+++ b/activesupport/lib/active_support/dependencies.rb
@@ -39,7 +39,7 @@ module Dependencies #:nodoc:
   end
   
   def remove_subclasses_for(*classes)
-    classes.each { |klass| klass.remove_subclasses }
+    Object.remove_subclasses_of(*classes)
   end
   
   # LoadingModules implement namespace-safe dynamic loading.
diff --git a/activesupport/test/core_ext/object_and_class_ext_test.rb b/activesupport/test/core_ext/object_and_class_ext_test.rb
index cf75159575..29b2f2fc8b 100644
--- a/activesupport/test/core_ext/object_and_class_ext_test.rb
+++ b/activesupport/test/core_ext/object_and_class_ext_test.rb
@@ -12,6 +12,20 @@ class RemoveSubsBaseClass
   end
 end
 class RemoveSubsSubClass < RemoveSubsBaseClass; end
+class RemoveSubsTestClass2; end
+class RemoveSubsBaseClass2
+  def self.add_ivar
+    @ivar = RemoveSubsTestClass2.new
+  end
+end
+class RemoveSubsSubClass2 < RemoveSubsBaseClass2; end
+class RemoveSubsTestClass3; end
+class RemoveSubsBaseClass3
+  def self.add_ivar
+    @ivar = RemoveSubsTestClass3.new
+  end
+end
+class RemoveSubsSubClass3 < RemoveSubsBaseClass3; end
 
 class ClassExtTest < Test::Unit::TestCase
   def test_methods
@@ -48,4 +62,18 @@ class ObjectTests < Test::Unit::TestCase
       flunk("ObjectSpace still contains RemoveSubsTestClass") if o.class == RemoveSubsTestClass
     end
   end
-end
-\ No newline at end of file
+
+  def test_remove_subclasses_of_multiple_classes_unsets_ivars
+    r2 = RemoveSubsSubClass2.new
+    RemoveSubsSubClass2.add_ivar
+    r3 = RemoveSubsSubClass3.new
+    RemoveSubsSubClass3.add_ivar
+    
+    Object.remove_subclasses_of(RemoveSubsBaseClass2, RemoveSubsBaseClass3)
+
+    GC.start
+    ObjectSpace.each_object do |o|
+      flunk("ObjectSpace still contains RemoveSubsTestClass") if o.class == RemoveSubsTestClass
+    end
+  end
+end