Common behavior with adding formats to lookup_context for TemplateRenderer and PartialRenderer

3 files changed, 11 insertions, 2 deletions

diff --git a/actionpack/lib/action_view/renderer/abstract_renderer.rb b/actionpack/lib/action_view/renderer/abstract_renderer.rb
index 0b5d3785d4..b79b89e142 100644
--- a/actionpack/lib/action_view/renderer/abstract_renderer.rb
+++ b/actionpack/lib/action_view/renderer/abstract_renderer.rb
@@ -37,5 +37,11 @@ module ActionView
     def instrument(name, options={})
       ActiveSupport::Notifications.instrument("render_#{name}.action_view", options){ yield }
     end
+
+    def prepend_formats(formats)
+      formats = Array(formats)
+      return if formats.empty? || @lookup_context.html_fallback_for_js
+      @lookup_context.formats = formats | @lookup_context.formats
+    end
   end
 end
diff --git a/actionpack/lib/action_view/renderer/partial_renderer.rb b/actionpack/lib/action_view/renderer/partial_renderer.rb
index 71fa05ab3e..f3300e470b 100644
--- a/actionpack/lib/action_view/renderer/partial_renderer.rb
+++ b/actionpack/lib/action_view/renderer/partial_renderer.rb
@@ -281,6 +281,8 @@ module ActionView
       @block   = block
       @details = extract_details(options)
 
+      prepend_formats(options[:formats])
+
       if String === partial
         @object     = options[:object]
         @path       = partial
diff --git a/actionpack/lib/action_view/renderer/template_renderer.rb b/actionpack/lib/action_view/renderer/template_renderer.rb
index a27d5dd1b1..d15e75637a 100644
--- a/actionpack/lib/action_view/renderer/template_renderer.rb
+++ b/actionpack/lib/action_view/renderer/template_renderer.rb
@@ -10,9 +10,10 @@ module ActionView
       template = determine_template(options)
       context  = @lookup_context
 
+      prepend_formats(template.formats)
+
       unless context.rendered_format
-        context.formats = template.formats unless template.formats.empty?
-        context.rendered_format = context.formats.first
+        context.rendered_format = template.formats.first || formats.last
       end
 
       render_template(template, options[:layout], options[:locals])