Partial not receiving all variables from :locals

In my controller I have:

- @item开发者_运维问答s.each do |item|
  = render :partial => 'item', :locals => { :item => item, :draggable => true }

And in the item partial I have:

%span{:id => "item_#{item.id}", :class => 'item'}
  = item.name
  - if defined?(draggable)
    = draggable_element "item_#{item.id}", :revert => true

This is not working, however, because defined?(draggable) returns false. The draggable_element is never rendered.

I know that item is passed through :locals because the rest of the partial renders. If I change the partial to read:

- if defined?(item)
  = draggable_element "item_#{item.id}", :revert => true

Then the draggable_element is rendered.

Any idea why :draggable is not getting passed to the partial?

Use local_assigns[:draggable] instead of defined?(draggable).

From the Rails API "Testing using defined? var will not work. This is an implementation restriction."

I've solved this problem in the past by throwing this into the top of the partial.

 <% draggable ||= nil %>

That allows me to do

 <% if draggable %>

So long as I don't try to make the distinction between draggable being nil and never being passed.