Fixed memory leak with Object#remove_subclasses_of, which inflicted a…

… Rails application running in development mode with a ~20KB leak per request #1289 [c.r.mcgrath@gmail.com]

git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@1569 5ecf4fe2-1ee6-0310-87b1-e25e094e27de

activesupport/CHANGELOG

@@ -1,5 +1,7 @@
 *SVN*
 
+* Fixed memory leak with Object#remove_subclasses_of, which inflicted a Rails application running in development mode with a ~20KB leak per request #1289 [c.r.mcgrath@gmail.com]
+
 * Made 1.year == 365.25.days to account for leap years.  This allows you to do User.find(:all, :conditions => ['birthday > ?', 50.years.ago]) without losing a lot of days.  #1488 [tuxie@dekadance.se]
 
 * Added an exception if calling id on nil to WhinyNil #584 [kevin-temp@writesoon.com]

activesupport/lib/active_support/core_ext/object_and_class.rb

@@ -1,6 +1,13 @@
 class Object #:nodoc:
   def remove_subclasses_of(superclass)
-    subclasses_of(superclass).each { |subclass| Object.send(:remove_const, subclass) rescue nil }
+    subclasses_of(superclass).each do |subclass|
+      ObjectSpace.each_object(Class) do |k|
+        if k.to_s == subclass
+          k.instance_variables.each { |v| k.send(:remove_instance_variable, v) }
+        end  
+      end   
+      Object.send(:remove_const, subclass) rescue nil
+    end 
   end
 
   def subclasses_of(superclass)

activesupport/test/core_ext/object_and_class_ext_test.rb

@@ -5,6 +5,13 @@ class ClassA; end
 class ClassB < ClassA; end
 class ClassC < ClassB; end
 class ClassD < ClassA; end
+class RemoveSubsTestClass; end
+class RemoveSubsBaseClass
+  def self.add_ivar
+    @ivar = RemoveSubsTestClass.new
+  end
+end
+class RemoveSubsSubClass < RemoveSubsBaseClass; end
 
 class ClassExtTest < Test::Unit::TestCase
   def test_methods
@@ -30,4 +37,15 @@ def test_suppress_supresses
     suppress(LoadError, ArgumentError) { raise LoadError }
     suppress(LoadError, ArgumentError) { raise ArgumentError }
   end
+
+  def test_remove_subclasses_of_unsets_ivars
+    r = RemoveSubsSubClass.new
+    RemoveSubsSubClass.add_ivar
+    RemoveSubsBaseClass.remove_subclasses
+
+    GC.start
+    ObjectSpace.each_object do |o|
+      flunk("ObjectSpace still contains RemoveSubsTestClass") if o.class == RemoveSubsTestClass
+    end
+  end
 end