4 files changed, 29 insertions, 9 deletions
diff --git a/activerecord/CHANGELOG b/activerecord/CHANGELOG
index 0147c8fd4d..e9c6884c7d 100644
--- a/activerecord/CHANGELOG
+++ b/activerecord/CHANGELOG
@@ -1,5 +1,7 @@
 *SVN*
 
+* Base#to_xml supports the nil="true" attribute like Hash#to_xml.  #8268 [Catfish]
+
 * Change plings to the more conventional quotes in the documentation. Closes #10104 [danger]
 
 * Fix HasManyThrough Association so it uses :conditions on the HasMany Association.  Closes #9729 [danger]
diff --git a/activerecord/lib/active_record/serializers/xml_serializer.rb b/activerecord/lib/active_record/serializers/xml_serializer.rb
index 28e9b3ddc6..693060f06e 100644
--- a/activerecord/lib/active_record/serializers/xml_serializer.rb
+++ b/activerecord/lib/active_record/serializers/xml_serializer.rb
@@ -271,6 +271,10 @@ module ActiveRecord #:nodoc:
           decorations[:type] = type
         end
 
+        if value.nil?
+          decorations[:nil] = true
+        end
+
         decorations
       end
 
diff --git a/activerecord/test/base_test.rb b/activerecord/test/base_test.rb
index e17b2a1b57..ee34d201b8 100755
--- a/activerecord/test/base_test.rb
+++ b/activerecord/test/base_test.rb
@@ -1555,7 +1555,7 @@ class BasicsTest < Test::Unit::TestCase
     assert xml.include?(%(<written-on type="datetime">#{written_on_in_current_timezone}</written-on>))
     assert xml.include?(%(<content type="yaml">--- Have a nice day\n</content>))
     assert xml.include?(%(<author-email-address>david@loudthinking.com</author-email-address>))
-    assert xml.match(%(<parent-id type="integer"></parent-id>))
+    assert xml.include?(%(<parent-id nil="true" type="integer"></parent-id>))
     if current_adapter?(:SybaseAdapter, :SQLServerAdapter, :OracleAdapter)
       assert xml.include?(%(<last-read type="datetime">#{last_read_in_current_timezone}</last-read>))
     else
diff --git a/activerecord/test/xml_serialization_test.rb b/activerecord/test/xml_serialization_test.rb
index a5da55cd8d..011f27ad14 100644
--- a/activerecord/test/xml_serialization_test.rb
+++ b/activerecord/test/xml_serialization_test.rb
@@ -78,29 +78,43 @@ class NilXmlSerializationTest < Test::Unit::TestCase
   end
 
   def test_should_serialize_string
-    assert_match %r{<name></name>},     @xml
+    assert_match %r{<name nil="true"></name>},     @xml
   end
   
   def test_should_serialize_integer
-    assert_match %r{<age type="integer"></age>}, @xml
+    assert %r{<age (.*)></age>}.match(@xml)
+    attributes = $1
+    assert_match %r{nil="true"}, attributes
+    assert_match %r{type="integer"}, attributes
   end
   
   def test_should_serialize_binary
-    assert_match %r{></avatar>},                     @xml
-    assert_match %r{<avatar(.*)(type="binary")},     @xml
-    assert_match %r{<avatar(.*)(encoding="base64")}, @xml
+    assert %r{<avatar (.*)></avatar>}.match(@xml)
+    attributes = $1
+    assert_match %r{type="binary"}, attributes
+    assert_match %r{encoding="base64"}, attributes
+    assert_match %r{nil="true"}, attributes
   end
   
   def test_should_serialize_datetime
-    assert_match %r{<created-at type=\"datetime\"></created-at>}, @xml
+    assert %r{<created-at (.*)></created-at>}.match(@xml)
+    attributes = $1
+    assert_match %r{nil="true"}, attributes
+    assert_match %r{type="datetime"}, attributes
   end
   
   def test_should_serialize_boolean
-    assert_match %r{<awesome type=\"boolean\"></awesome>}, @xml
+    assert %r{<awesome (.*)></awesome>}.match(@xml)
+    attributes = $1
+    assert_match %r{type="boolean"}, attributes
+    assert_match %r{nil="true"}, attributes
   end
   
   def test_should_serialize_yaml
-    assert_match %r{<preferences type=\"yaml\"></preferences>}, @xml
+    assert %r{<preferences(.*)></preferences>}.match(@xml)
+    attributes = $1
+    assert_match %r{type="yaml"}, attributes
+    assert_match %r{nil="true"}, attributes
   end
 end