to_xml with :include should skip_instruct on the included records [ra…

…ils#4506 state:resolved]

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

activerecord/lib/active_record/serializers/xml_serializer.rb

@@ -197,7 +197,7 @@ def add_includes
     # TODO This can likely be cleaned up to simple use ActiveSupport::XmlMini.to_tag as well.
     def add_associations(association, records, opts)
       association_name = association.to_s.singularize
-      merged_options   = options.merge(opts).merge!(:root => association_name)
+      merged_options   = options.merge(opts).merge!(:root => association_name, :skip_instruct => true)
 
       if records.is_a?(Enumerable)
         tag  = ActiveSupport::XmlMini.rename_key(association.to_s, options)

activerecord/test/cases/serialization_test.rb

@@ -44,4 +44,11 @@ def test_serialize_should_allow_attribute_except_filtering
       assert_equal @contact_attributes[:awesome], contact.awesome, "For #{format}"
     end
   end
+
+  def test_serialize_should_xml_skip_instruct_for_included_records
+    @contact.alternative = Contact.new(:name => 'Copa Cabana')
+    @serialized = @contact.to_xml(:include => [ :alternative ])
+    assert_equal @serialized.index('<?xml '), 0
+    assert_nil @serialized.index('<?xml ', 1)
+  end
 end

activerecord/test/models/contact.rb

@@ -13,4 +13,6 @@ def self.column(name, sql_type = nil, options = {})
   column :preferences, :string
 
   serialize :preferences
-end
+
+  belongs_to :alternative, :class_name => 'Contact'
+end