From 0f0919460c015dfe05eb52900aeae3dddc4aeb62 Mon Sep 17 00:00:00 2001
From: Tom Lea <contrib@tomlea.co.uk>
Date: Mon, 11 Aug 2008 14:12:53 +0100
Subject: [PATCH] Made attribute_changed? realize when attributes are changed back

---
 activerecord/lib/active_record/dirty.rb |    5 +++-
 activerecord/test/cases/dirty_test.rb   |   36 +++++++++++++++++++++++++++++++
 2 files changed, 40 insertions(+), 1 deletions(-)

diff --git a/activerecord/lib/active_record/dirty.rb b/activerecord/lib/active_record/dirty.rb
index 4ce0356..f2ec258 100644
--- a/activerecord/lib/active_record/dirty.rb
+++ b/activerecord/lib/active_record/dirty.rb
@@ -123,7 +123,10 @@ module ActiveRecord
         attr = attr.to_s
 
         # The attribute already has an unsaved change.
-        unless changed_attributes.include?(attr)
+        if changed_attributes.include?(attr)
+          old = changed_attributes[attr]
+          changed_attributes.delete(attr) unless field_changed?(attr, old, value)
+        else
           old = clone_attribute_value(:read_attribute, attr)
           changed_attributes[attr] = old if field_changed?(attr, old, value)
         end
diff --git a/activerecord/test/cases/dirty_test.rb b/activerecord/test/cases/dirty_test.rb
index e5e0220..44a65d1 100644
--- a/activerecord/test/cases/dirty_test.rb
+++ b/activerecord/test/cases/dirty_test.rb
@@ -190,6 +190,42 @@ class DirtyTest < ActiveRecord::TestCase
     pirate.reload
     assert !pirate.changed?
   end
+  
+  def test_reverted_changes_are_not_dirty
+    phrase = "shiver me timbers"
+    pirate = Pirate.create!(:catchphrase => phrase)
+    pirate.catchphrase = "*hic*"
+    assert pirate.changed?
+    pirate.catchphrase = phrase
+    assert !pirate.changed?    
+  end
+
+  def test_reverted_changes_are_not_dirty_after_multiple_changes
+    phrase = "shiver me timbers"
+    pirate = Pirate.create!(:catchphrase => phrase)
+    10.times do |i|
+      pirate.catchphrase = "*hic*" * i
+      assert pirate.changed?
+    end
+    assert pirate.changed?
+    pirate.catchphrase = phrase
+    assert !pirate.changed?    
+  end
+
+
+  def test_reverted_changes_are_not_dirty_going_from_nil_to_value_and_back
+    pirate = Pirate.create!(:catchphrase => "Yar!")
+    
+    pirate.parrot_id = 1
+    assert pirate.changed?
+    assert pirate.parrot_id_changed?
+    assert !pirate.catchphrase_changed?
+    
+    pirate.parrot_id = nil
+    assert !pirate.changed?    
+    assert !pirate.parrot_id_changed?
+    assert !pirate.catchphrase_changed?
+  end
 
   private
     def with_partial_updates(klass, on = true)
-- 
1.5.2.4