Don't alter the Hash passed to attributes=, closes #3385

git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@3417 5ecf4fe2-1ee6-0310-87b1-e25e094e27de

activerecord/lib/active_record/base.rb

@@ -1334,8 +1334,9 @@ module ActiveRecord #:nodoc:
       # from this form of mass-assignment by using the +attr_protected+ macro. Or you can alternatively
       # specify which attributes *can* be accessed in with the +attr_accessible+ macro. Then all the
       # attributes not included in that won't be allowed to be mass-assigned.
-      def attributes=(attributes)
-        return if attributes.nil?
+      def attributes=(attrs)
+        return if attrs.nil?
+        attributes= attrs.dup
         attributes.stringify_keys!
 
         multi_parameter_attributes = []

activerecord/test/base_test.rb

@@ -133,8 +133,19 @@ class BasicsTest < Test::Unit::TestCase
     topic = Topic.new
     topic.title = "New Topic"
     topic.save
-    topicReloaded = Topic.find(topic.id)
-    assert_equal("New Topic", topicReloaded.title)
+    topic_reloaded = Topic.find(topic.id)
+    assert_equal("New Topic", topic_reloaded.title)
+  end
+    
+  def test_hashes_not_mangled
+    new_topic = { :title => "New Topic" }
+    new_topic_values = { :title => "AnotherTopic" }
+
+    topic = Topic.new(new_topic)
+    assert_equal new_topic[:title], topic.title
+
+    topic.attributes= new_topic_values
+    assert_equal new_topic_value[:title], topic.title
   end
   
   def test_create_many