Allow ARStore::Session to indicate that it should not be reloaded in dev mode

git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@2627 5ecf4fe2-1ee6-0310-87b1-e25e094e27de

actionpack/lib/action_controller/session/active_record_store.rb

@@ -46,6 +46,11 @@ class CGI
 
         class << self
 
+          # Don't try to reload ARStore::Session in dev mode.
+          def reloadable? #:nodoc:
+            false
+          end
+          
           def data_column_size_limit
             connection.columns(table_name).find {|column| column.name == 'data'}.limit
           end

activerecord/lib/active_record/base.rb

@@ -256,13 +256,27 @@ module ActiveRecord #:nodoc:
       @@subclasses[self] << child
       super
     end
+    
+    # Allow all subclasses of AR::Base to be reloaded in dev mode, unless they
+    # explicitly decline the honor. USE WITH CAUTION. Only AR subclasses kept
+    # in the framework should use the flag, so #reset_subclasses and so forth
+    # leave it alone.
+    def self.reloadable? #:nodoc:
+      true
+    end
 
     def self.reset_subclasses
+      nonreloadables = []
       subclasses.each do |klass|
+        unless klass.reloadable?
+          nonreloadables << klass
+          next
+        end
         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
+      @@subclasses = {}
+      nonreloadables.each { |klass| (@@subclasses[klass.superclass] ||= []) << klass }
     end
 
     @@subclasses = {}