Make [7169] work as expected with indented XML.

git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@7171 5ecf4fe2-1ee6-0310-87b1-e25e094e27de

activerecord/lib/active_record/xml_serialization.rb

@@ -207,8 +207,12 @@ def add_includes
             records = @record.send(association).to_a
             tag = association.to_s
             tag = tag.dasherize if dasherize?
-            builder.tag!(tag, :type => :array) do
-              records.each { |r| r.to_xml(opts.merge(:root=>r.class.to_s.underscore)) }
+            if records.empty?
+              builder.tag!(tag, :type => :array)
+            else
+              builder.tag!(tag, :type => :array) do
+                records.each { |r| r.to_xml(opts.merge(:root=>r.class.to_s.underscore)) }
+              end
             end
           when :has_one, :belongs_to
             if record = @record.send(association)

activerecord/test/xml_serialization_test.rb

@@ -165,9 +165,10 @@ def test_should_not_call_methods_on_associations_that_dont_respond
   
   def test_should_include_empty_has_many_as_empty_array
     authors(:david).posts.delete_all    
-    xml = authors(:david).to_xml :include=>:posts, :indent => 0
+    xml = authors(:david).to_xml :include=>:posts, :indent => 2
     
-    assert_match %r{<posts type="array"></posts>}, xml
+    assert_equal [], Hash.from_xml(xml)['author']['posts']
+    assert_match %r{^  <posts type="array"/>}, xml
   end
   
 end
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