squash the memleak in dev mode finally (fingers crossed, here)

git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@2620 5ecf4fe2-1ee6-0310-87b1-e25e094e27de

activerecord/lib/active_record/base.rb

@@ -258,6 +258,10 @@ def self.inherited(child) #:nodoc:
     end
 
     def self.reset_subclasses
+      subclasses.each do |klass|
+        klass.instance_variables.each { |var| klass.send(:remove_instance_variable, var) }
+        klass.instance_methods(false).each { |m| klass.send :undef_method, m }
+      end
       @@subclasses.clear
     end
 

activerecord/test/base_test.rb

@@ -1024,6 +1024,25 @@ def test_interpolate_sql
     assert_nothing_raised { Category.new.send(:interpolate_sql, 'foo bar} baz') }
   end
 
+  def test_dev_mode_memory_leak
+    counts = []
+    2.times do
+      require_dependency 'fixtures/company'
+      Firm.find(:first)
+      Dependencies.clear
+      ActiveRecord::Base.reset_subclasses
+      Dependencies.remove_subclasses_for(ActiveRecord::Base)
+
+      GC.start
+
+      count = 0
+      ObjectSpace.each_object(Proc) { count += 1 }
+      counts << count
+    end
+    assert counts.last <= counts.first,
+      "expected last count (#{counts.last}) to be <= first count (#{counts.first})"
+  end
+
   private
 
     def assert_readers(model, exceptions)