update_attribute should not update readonly attributes

[#5106 state:resolved]

Signed-off-by: José Valim <jose.valim@gmail.com>

activerecord/lib/active_record/persistence.rb

@@ -105,6 +105,8 @@ def becomes(klass)
     # Updates a single attribute and saves the record without going through the normal validation procedure
     # or callbacks. This is especially useful for boolean flags on existing records.
     def update_attribute(name, value)
+      raise ActiveRecordError, "#{name.to_s} is marked as readonly" if self.class.readonly_attributes.include? name.to_s
+
       changes = record_update_timestamps || {}
 
       if name

activerecord/test/cases/persistence_test.rb

@@ -17,13 +17,14 @@
 require 'models/minimalistic'
 require 'models/warehouse_thing'
 require 'models/parrot'
+require 'models/minivan'
 require 'models/loose_person'
 require 'rexml/document'
 require 'active_support/core_ext/exception'
 
 class PersistencesTest < ActiveRecord::TestCase
 
-  fixtures :topics, :companies, :developers, :projects, :computers, :accounts, :minimalistics, 'warehouse-things', :authors, :categorizations, :categories, :posts
+  fixtures :topics, :companies, :developers, :projects, :computers, :accounts, :minimalistics, 'warehouse-things', :authors, :categorizations, :categories, :posts, :minivans
 
   def test_create
     topic = Topic.new
@@ -220,6 +221,11 @@ def test_update_attribute
     assert !Topic.find(1).approved?
   end
 
+  def test_update_attribute_for_readonly_attribute
+    minivan = Minivan.find('m1')
+    assert_raises(ActiveRecord::ActiveRecordError) { minivan.update_attribute(:color, 'black') }
+  end
+
   def test_update_attribute_with_one_changed_and_one_updated
     t = Topic.order('id').limit(1).first
     title, author_name = t.title, t.author_name

activerecord/test/fixtures/minivans.yml

@@ -2,3 +2,4 @@ cool_first:
   minivan_id: m1
   name: my_minivan
   speedometer_id: s1
+  color: blue

activerecord/test/models/minivan.rb

@@ -3,4 +3,7 @@ class Minivan < ActiveRecord::Base
 
   belongs_to :speedometer
   has_one :dashboard, :through => :speedometer
-end
+
+  attr_readonly :color
+
+end

activerecord/test/schema/schema.rb

@@ -300,6 +300,7 @@ def create_table(*args, &block)
     t.string :minivan_id
     t.string :name
     t.string :speedometer_id
+    t.string :color
   end
 
   create_table :minimalistics, :force => true do |t|