10 files changed, 124 insertions, 5 deletions
diff --git a/activerecord/CHANGELOG b/activerecord/CHANGELOG
index 50203608c2..0f6a31d679 100644
--- a/activerecord/CHANGELOG
+++ b/activerecord/CHANGELOG
@@ -1,5 +1,16 @@
 *Rails 3.2.0 (unreleased)*
 
+* Added ActiveRecord::Base.store for declaring simple single-column key/value stores [DHH]
+
+    class User < ActiveRecord::Base
+      store :settings, accessors: [ :color, :homepage ]
+    end
+    
+    u = User.new(color: 'black', homepage: '37signals.com')
+    u.color                          # Accessor stored attribute
+    u.settings[:country] = 'Denmark' # Any attribute, even if not specified with an accessor
+
+
 * MySQL: case-insensitive uniqueness validation avoids calling LOWER when
   the column already uses a case-insensitive collation. Fixes #561.
 
diff --git a/activerecord/lib/active_record.rb b/activerecord/lib/active_record.rb
index 132dc12680..3572c640eb 100644
--- a/activerecord/lib/active_record.rb
+++ b/activerecord/lib/active_record.rb
@@ -69,6 +69,7 @@ module ActiveRecord
     autoload :Schema
     autoload :SchemaDumper
     autoload :Serialization
+    autoload :Store
     autoload :SessionStore
     autoload :Timestamp
     autoload :Transactions
diff --git a/activerecord/lib/active_record/base.rb b/activerecord/lib/active_record/base.rb
index 7a9654ffd8..360e494af1 100644
--- a/activerecord/lib/active_record/base.rb
+++ b/activerecord/lib/active_record/base.rb
@@ -2145,7 +2145,7 @@ MSG
     # AutosaveAssociation needs to be included before Transactions, because we want
     # #save_with_autosave_associations to be wrapped inside a transaction.
     include AutosaveAssociation, NestedAttributes
-    include Aggregations, Transactions, Reflection, Serialization
+    include Aggregations, Transactions, Reflection, Serialization, Store
 
     NilClass.add_whiner(self) if NilClass.respond_to?(:add_whiner)
 
diff --git a/activerecord/lib/active_record/errors.rb b/activerecord/lib/active_record/errors.rb
index 96870cb338..fc80f3081e 100644
--- a/activerecord/lib/active_record/errors.rb
+++ b/activerecord/lib/active_record/errors.rb
@@ -99,6 +99,16 @@ module ActiveRecord
   #
   # Read more about optimistic locking in ActiveRecord::Locking module RDoc.
   class StaleObjectError < ActiveRecordError
+    attr_reader :record, :attempted_action
+
+    def initialize(record, attempted_action)
+      @record = record
+      @attempted_action = attempted_action
+    end
+
+    def message
+      "Attempted to #{attempted_action} a stale object: #{record.class.name}"
+    end
   end
 
   # Raised when association is being configured improperly or
diff --git a/activerecord/lib/active_record/locking/optimistic.rb b/activerecord/lib/active_record/locking/optimistic.rb
index d9ad7e4132..2df3309648 100644
--- a/activerecord/lib/active_record/locking/optimistic.rb
+++ b/activerecord/lib/active_record/locking/optimistic.rb
@@ -103,7 +103,7 @@ module ActiveRecord
             affected_rows = connection.update stmt
 
             unless affected_rows == 1
-              raise ActiveRecord::StaleObjectError, "Attempted to update a stale object: #{self.class.name}"
+              raise ActiveRecord::StaleObjectError.new(self, "update")
             end
 
             affected_rows
@@ -127,7 +127,7 @@ module ActiveRecord
             affected_rows = self.class.unscoped.where(predicate).delete_all
 
             unless affected_rows == 1
-              raise ActiveRecord::StaleObjectError, "Attempted to delete a stale object: #{self.class.name}"
+              raise ActiveRecord::StaleObjectError.new(self, "destroy")
             end
           end
 
diff --git a/activerecord/lib/active_record/store.rb b/activerecord/lib/active_record/store.rb
new file mode 100644
index 0000000000..d5910df891
--- /dev/null
+++ b/activerecord/lib/active_record/store.rb
@@ -0,0 +1,49 @@
+module ActiveRecord
+  # Store gives you a thin wrapper around serialize for the purpose of storing hashes in a single column.
+  # It's like a simple key/value store backed into your record when you don't care about being able to
+  # query that store outside the context of a single record.
+  #
+  # You can then declare accessors to this store that are then accessible just like any other attribute
+  # of the model. This is very helpful for easily exposing store keys to a form or elsewhere that's
+  # already built around just accessing attributes on the model.
+  #
+  # Make sure that you declare the database column used for the serialized store as a text, so there's
+  # plenty of room.
+  #
+  # Examples:
+  #
+  #   class User < ActiveRecord::Base
+  #     store :settings, accessors: [ :color, :homepage ]
+  #   end
+  #   
+  #   u = User.new(color: 'black', homepage: '37signals.com')
+  #   u.color                          # Accessor stored attribute
+  #   u.settings[:country] = 'Denmark' # Any attribute, even if not specified with an accessor
+  #
+  #   # Add additional accessors to an existing store through store_accessor
+  #   class SuperUser < User
+  #     store_accessor :settings, :privileges, :servants
+  #   end
+  module Store
+    extend ActiveSupport::Concern
+  
+    module ClassMethods
+      def store(store_attribute, options = {})
+        serialize store_attribute, Hash
+        store_accessor(store_attribute, options[:accessors]) if options.has_key? :accessors
+      end
+
+      def store_accessor(store_attribute, *keys)
+        Array(keys).flatten.each do |key|
+          define_method("#{key}=") do |value|
+            send(store_attribute)[key] = value
+          end
+    
+          define_method(key) do
+            send(store_attribute)[key]
+          end
+        end
+      end
+    end
+  end
+end
+\ No newline at end of file
diff --git a/activerecord/test/cases/locking_test.rb b/activerecord/test/cases/locking_test.rb
index 61baa55027..e9bd7f07b6 100644
--- a/activerecord/test/cases/locking_test.rb
+++ b/activerecord/test/cases/locking_test.rb
@@ -125,6 +125,24 @@ class OptimisticLockingTest < ActiveRecord::TestCase
     assert_raise(ActiveRecord::StaleObjectError) { p2.save! }
   end
 
+  def test_lock_exception_record
+    p1 = Person.new(:first_name => 'mira')
+    assert_equal 0, p1.lock_version
+
+    p1.first_name = 'mira2'
+    p1.save!
+    p2 = Person.find(p1.id)
+    assert_equal 0, p1.lock_version
+    assert_equal 0, p2.lock_version
+
+    p1.first_name = 'mira3'
+    p1.save!
+
+    p2.first_name = 'sue'
+    error = assert_raise(ActiveRecord::StaleObjectError) { p2.save! }
+    assert_equal(error.record.object_id, p2.object_id)
+  end
+
   def test_lock_new_with_nil
     p1 = Person.new(:first_name => 'anika')
     p1.save!
@@ -141,7 +159,6 @@ class OptimisticLockingTest < ActiveRecord::TestCase
     assert_equal 1, p1.lock_version
   end
 
-
   def test_lock_column_name_existing
     t1 = LegacyThing.find(1)
     t2 = LegacyThing.find(1)
diff --git a/activerecord/test/cases/store_test.rb b/activerecord/test/cases/store_test.rb
new file mode 100644
index 0000000000..fb77220875
--- /dev/null
+++ b/activerecord/test/cases/store_test.rb
@@ -0,0 +1,29 @@
+require 'cases/helper'
+require 'models/admin'
+require 'models/admin/user'
+
+class StoreTest < ActiveRecord::TestCase
+  setup do
+    @john = Admin::User.create(:name => 'John Doe', :color => 'black')
+  end
+
+  test "reading store attributes through accessors" do
+    assert_equal 'black', @john.color
+    assert_nil @john.homepage
+  end
+
+  test "writing store attributes through accessors" do
+    @john.color = 'red'
+    @john.homepage = '37signals.com'
+
+    assert_equal 'red', @john.color
+    assert_equal '37signals.com', @john.homepage
+  end
+
+  test "accessing attributes not exposed by accessors" do
+    @john.settings[:icecream] = 'graeters'
+    @john.save
+
+    assert 'graeters', @john.reload.settings[:icecream]
+  end
+end
diff --git a/activerecord/test/models/admin/user.rb b/activerecord/test/models/admin/user.rb
index 74bb21551e..c12c88e195 100644
--- a/activerecord/test/models/admin/user.rb
+++ b/activerecord/test/models/admin/user.rb
@@ -1,3 +1,4 @@
 class Admin::User < ActiveRecord::Base
   belongs_to :account
-end
-\ No newline at end of file
+  store :settings, :accessors => [ :color, :homepage ]
+end
diff --git a/activerecord/test/schema/schema.rb b/activerecord/test/schema/schema.rb
index 9d5ad16a3c..bb08f5c181 100644
--- a/activerecord/test/schema/schema.rb
+++ b/activerecord/test/schema/schema.rb
@@ -37,6 +37,7 @@ ActiveRecord::Schema.define do
 
   create_table :admin_users, :force => true do |t|
     t.string :name
+    t.text :settings
     t.references :account
   end