Allow form_for and fields_for to work with indexed form inputs. [Jeremy Kemper, Matt Lyon]

git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@4613 5ecf4fe2-1ee6-0310-87b1-e25e094e27de

actionpack/CHANGELOG

 *SVN*
 
+* Allow form_for and fields_for to work with indexed form inputs.  [Jeremy Kemper, Matt Lyon]
+
+  <% form_for 'post[]', @post do |f| -%>
+  <% end -%>
+
 * Remove leak in development mode by replacing define_method with module_eval. [Nicholas Seckar]
 
 * Provide support for decimal columns to form helpers. Closes #5672. [dave@pragprog.com]

actionpack/lib/action_view/helpers/form_helper.rb

@@ -238,7 +238,11 @@ def initialize(object_name, method_name, template_object, local_binding = nil, o
         @template_object, @local_binding = template_object, local_binding
         @object = object
         if @object_name.sub!(/\[\]$/,"")
-          @auto_index = @template_object.instance_variable_get("@#{Regexp.last_match.pre_match}").id_before_type_cast
+          if object ||= @template_object.instance_variable_get("@#{Regexp.last_match.pre_match}") and object.respond_to?(:id_before_type_cast)
+            @auto_index = object.id_before_type_cast
+          else
+            raise ArgumentError, "object[] naming but object param and @object var don't exist or don't respond to id_before_type_cast: #{object.inspect}"
+          end
         end
       end
 

actionpack/test/template/form_helper_test.rb

@@ -279,6 +279,24 @@ def test_form_for_without_object
 
     assert_dom_equal expected, _erbout
   end
+  
+  def test_form_for_with_index
+    _erbout = ''
+    
+    form_for("post[]", @post) do |f|
+      _erbout.concat f.text_field(:title)
+      _erbout.concat f.text_area(:body)
+      _erbout.concat f.check_box(:secret)
+    end
+    
+    expected = 
+      "<form action='http://www.example.com' method='post'>" +
+      "<input name='post[123][title]' size='30' type='text' id='post_title' value='Hello World' />" +
+      "<textarea name='post[123][body]' id='post_body' rows='20' cols='40'>Back to the hill and over it again!</textarea>" +
+      "<input name='post[123][secret]' checked='checked' type='checkbox' id='post_secret' value='1' />" +
+      "<input name='post[123][secret]' type='hidden' value='0' />" +
+      "</form>"
+  end
 
   def test_fields_for
     _erbout = ''