Support configuration on ActiveRecord::Model.

The problem: We need to be able to specify configuration in a way that
can be inherited to models that include ActiveRecord::Model. So it is
no longer sufficient to put 'top level' config on ActiveRecord::Base,
but we do want configuration specified on ActiveRecord::Base and
descendants to continue to work.

So we need something like class_attribute that can be defined on a
module but that is inherited when ActiveRecord::Model is included.

The solution: added ActiveModel::Configuration module which provides a
config_attribute macro. It's a bit specific hence I am not putting this
in Active Support or making it a 'public API' at present.

1 files changed, 12 insertions, 10 deletions

diff --git a/activemodel/lib/active_model/mass_assignment_security.rb b/activemodel/lib/active_model/mass_assignment_security.rb
index c895968f77..9b12d9d281 100644
--- a/activemodel/lib/active_model/mass_assignment_security.rb
+++ b/activemodel/lib/active_model/mass_assignment_security.rb
@@ -10,11 +10,13 @@ module ActiveModel
     extend ActiveSupport::Concern
 
     included do
-      class_attribute :_accessible_attributes
-      class_attribute :_protected_attributes
-      class_attribute :_active_authorizer
+      extend ActiveModel::Configuration
 
-      class_attribute :_mass_assignment_sanitizer
+      config_attribute :_accessible_attributes
+      config_attribute :_protected_attributes
+      config_attribute :_active_authorizer
+
+      config_attribute :_mass_assignment_sanitizer
       self.mass_assignment_sanitizer = :logger
     end
 
@@ -56,7 +58,7 @@ module ActiveModel
     # You can specify your own sanitizer object eg. MySanitizer.new.
     # See <tt>ActiveModel::MassAssignmentSecurity::LoggerSanitizer</tt> for example implementation.
     #
-    # 
+    #
     module ClassMethods
       # Attributes named in this macro are protected from mass-assignment
       # whenever attributes are sanitized before assignment. A role for the
@@ -70,13 +72,13 @@ module ActiveModel
       #
       #   class Customer
       #     include ActiveModel::MassAssignmentSecurity
-      #   
+      #
       #     attr_accessor :name, :email, :logins_count
-      #   
+      #
       #     attr_protected :logins_count
       #     # Suppose that admin can not change email for customer
-      #     attr_protected :logins_count, :email, :as => :admin 
-      #   
+      #     attr_protected :logins_count, :email, :as => :admin
+      #
       #     def assign_attributes(values, options = {})
       #       sanitize_for_mass_assignment(values, options[:as]).each do |k, v|
       #         send("#{k}=", v)
@@ -99,7 +101,7 @@ module ActiveModel
       #   customer.name          # => "David"
       #   customer.email # => nil
       #   customer.logins_count    # => nil
-      #   
+      #
       #   customer.email = "c@d.com"
       #   customer.email # => "c@d.com"
       #