Allow data attributes to be set as a first-level option for form_for,…

… so you can write `form_for @record, data: { behavior: 'autosave' }` instead of `form_for @record, html: { data: { behavior: 'autosave' } }` *DHH*

actionpack/CHANGELOG.md

@@ -1,5 +1,7 @@
 ## Rails 4.0.0 (unreleased) ##
 
+*   Allow data attributes to be set as a first-level option for form_for, so you can write `form_for @record, data: { behavior: 'autosave' }` instead of `form_for @record, html: { data: { behavior: 'autosave' } }` *DHH*
+
 *   Deprecate `button_to_function` and `link_to_function` helpers.
 
     We recommend the use of Unobtrusive JavaScript instead. For example:

actionpack/lib/action_view/helpers/form_helper.rb

@@ -323,6 +323,24 @@ module FormHelper
       #     ...
       #   </form>
       #
+      # === Setting HTML options
+      #
+      # You can set data attributes directly by passing in a data hash, but all other HTML options must be wrapped in
+      # the HTML key. Example:
+      #
+      #   <%= form_for(@post, data: { behavior: "autosave" }, html: { name: "go" }) do |f| %>
+      #     ...
+      #   <% end %>
+      #
+      # The HTML generated for this would be:
+      #
+      #   <form action='http://www.example.com' method='post' data-behavior='autosave' name='go'>
+      #     <div style='margin:0;padding:0;display:inline'>
+      #       <input name='_method' type='hidden' value='put' />
+      #     </div>
+      #     ...
+      #   </form>
+      #
       # === Removing hidden model id's
       #
       # The form_for method automatically includes the model id as a hidden field in the form.
@@ -409,6 +427,7 @@ def form_for(record, options = {}, &proc)
           apply_form_for_options!(record, object, options)
         end
 
+        options[:html][:data]   = options.delete(:data)   if options.has_key?(:data)
         options[:html][:remote] = options.delete(:remote) if options.has_key?(:remote)
         options[:html][:method] = options.delete(:method) if options.has_key?(:method)
         options[:html][:authenticity_token] = options.delete(:authenticity_token)

actionpack/test/template/form_helper_test.rb

@@ -2637,6 +2637,12 @@ def test_form_for_with_default_method_as_patch
     assert_dom_equal expected, output_buffer
   end
 
+  def test_form_for_with_data_attributes
+    form_for(@post, data: { behavior: "stuff" }, remote: true) {}
+    assert_match %r|data-behavior="stuff"|, output_buffer
+    assert_match %r|data-remote="true"|, output_buffer
+  end
+
   def test_fields_for_returns_block_result
     output = fields_for(Post.new) { |f| "fields" }
     assert_equal "fields", output