MassAssignmentProtection: consider 'id' insensetive in StrictSanitizer

In order to use StrictSanitizer in test mode
Consider :id as not sensetive attribute that can be filtered from
mass assignement without exception.

activemodel/lib/active_model/mass_assignment_security/sanitizer.rb

@@ -44,8 +44,13 @@ module ActiveModel
 
     class StrictSanitizer < Sanitizer
       def process_removed_attributes(attrs)
+        return if (attrs - insensitive_attributes).empty?
         raise ActiveModel::MassAssignmentSecurity::Error, "Can't mass-assign protected attributes: #{attrs.join(', ')}"
       end
+
+      def insensitive_attributes
+        ['id']
+      end
     end
 
     class Error < StandardError

activemodel/test/cases/mass_assignment_security/sanitizer_test.rb

@@ -7,7 +7,7 @@ class SanitizerTest < ActiveModel::TestCase
 
   class Authorizer < ActiveModel::MassAssignmentSecurity::PermissionSet
     def deny?(key)
-      key.in?(['admin'])
+      ['admin', 'id'].include?(key)
     end
   end
 
@@ -40,4 +40,12 @@ class SanitizerTest < ActiveModel::TestCase
     end
   end
 
+  test "mass assignment insensitive attributes" do
+    original_attributes = {'id' => 1, 'first_name' => 'allowed'}
+
+    assert_nothing_raised do
+      @strict_sanitizer.sanitize(original_attributes, @authorizer)
+    end
+  end
+
 end

railties/lib/rails/generators/rails/app/templates/config/environments/test.rb.tt

@@ -34,6 +34,11 @@
   # like if you have constraints or database-specific column types
   # config.active_record.schema_format = :sql
 
+  <%- unless options.skip_active_record? -%>
+  # Raise exception on mass assignment protection for ActiveRecord models
+  config.active_record.mass_assignment_sanitizer = :strict
+  <%- end -%>
+
   # Print deprecation notices to the stderr
   config.active_support.deprecation = :stderr
 end