gist.rb

module DebugPartialRenderer
  def render(context, options, block)
    msg = "rendering '#{options[:partial]}' with locals '#{(options[:locals] || {}).keys}'"
    "<!-- start #{msg}-->\n#{super(context, options, block)}\n<!-- end #{msg}-->\n".html_safe
  end
end


if Rails.env.development?
  ActionView::PartialRenderer.prepend(DebugPartialRenderer)
end