Allow collection helpers with block to access current object in the collection

This gives a lot more flexibility to the user, for instance to generate
a collection of check boxes and labels, allowing to add custom classes
or data-* attributes to the label/check_box using another object
attribute.

This basically mimics options_for_select functionality that accepts a
third option for each item to generate html attributes for each option.

actionpack/lib/action_view/helpers/tags/collection_check_boxes.rb

@@ -14,9 +14,9 @@ def check_box(extra_html_options={})
         end
 
         def render
-          rendered_collection = render_collection do |value, text, default_html_options|
+          rendered_collection = render_collection do |item, value, text, default_html_options|
             default_html_options[:multiple] = true
-            builder = instantiate_builder(CheckBoxBuilder, value, text, default_html_options)
+            builder = instantiate_builder(CheckBoxBuilder, item, value, text, default_html_options)
 
             if block_given?
               yield builder

actionpack/lib/action_view/helpers/tags/collection_helpers.rb

@@ -3,13 +3,14 @@ module Helpers
     module Tags
       module CollectionHelpers
         class Builder
-          attr_reader :text, :value
+          attr_reader :object, :text, :value
 
-          def initialize(template_object, object_name, method_name,
+          def initialize(template_object, object_name, method_name, object,
                          sanitized_attribute_name, text, value, input_html_options)
             @template_object = template_object
             @object_name = object_name
             @method_name = method_name
+            @object = object
             @sanitized_attribute_name = sanitized_attribute_name
             @text = text
             @value = value
@@ -32,8 +33,8 @@ def initialize(object_name, method_name, template_object, collection, value_meth
 
         private
 
-        def instantiate_builder(builder_class, value, text, html_options)
-          builder_class.new(@template_object, @object_name, @method_name,
+        def instantiate_builder(builder_class, item, value, text, html_options)
+          builder_class.new(@template_object, @object_name, @method_name, item,
                             sanitize_attribute_name(value), text, value, html_options)
         end
 
@@ -71,7 +72,7 @@ def render_collection #:nodoc:
             text  = value_for_collection(item, @text_method)
             default_html_options = default_html_options_for_collection(item, value)
 
-            yield value, text, default_html_options
+            yield item, value, text, default_html_options
           end.join.html_safe
         end
       end

actionpack/lib/action_view/helpers/tags/collection_radio_buttons.rb

@@ -14,8 +14,8 @@ def radio_button(extra_html_options={})
         end
 
         def render
-          render_collection do |value, text, default_html_options|
-            builder = instantiate_builder(RadioButtonBuilder, value, text, default_html_options)
+          render_collection do |item, value, text, default_html_options|
+            builder = instantiate_builder(RadioButtonBuilder, item, value, text, default_html_options)
 
             if block_given?
               yield builder

actionpack/test/template/form_collections_helper_test.rb

@@ -123,6 +123,19 @@ def with_collection_check_boxes(*args, &block)
     end
   end
 
+  test 'collection radio with block helpers allows access to the current object item in the collection to access extra properties' do
+    with_collection_radio_buttons :user, :active, [true, false], :to_s, :to_s do |b|
+      b.label(:class => b.object) { b.radio_button + b.text }
+    end
+
+    assert_select 'label.true[for=user_active_true]', 'true' do
+      assert_select 'input#user_active_true[type=radio]'
+    end
+    assert_select 'label.false[for=user_active_false]', 'false' do
+      assert_select 'input#user_active_false[type=radio]'
+    end
+  end
+
   test 'collection radio buttons with fields for' do
     collection = [Category.new(1, 'Category 1'), Category.new(2, 'Category 2')]
     @output_buffer = fields_for(:post) do |p|
@@ -298,4 +311,17 @@ def with_collection_check_boxes(*args, &block)
       assert_select 'input#user_active_false[type=checkbox]'
     end
   end
+
+  test 'collection check boxes with block helpers allows access to the current object item in the collection to access extra properties' do
+    with_collection_check_boxes :user, :active, [true, false], :to_s, :to_s do |b|
+      b.label(:class => b.object) { b.check_box + b.text }
+    end
+
+    assert_select 'label.true[for=user_active_true]', 'true' do
+      assert_select 'input#user_active_true[type=checkbox]'
+    end
+    assert_select 'label.false[for=user_active_false]', 'false' do
+      assert_select 'input#user_active_false[type=checkbox]'
+    end
+  end
 end