rails 3.2 with jbuilder swallowing errors, instead rendering missing partial - ruby-on-rails

Question

I'm using Rails 3.2.21 with JBuilder.
I have an example where I'm using an a JBuilder partial inside of a js.erb file to pre populate some fields:
var orderData = <%= raw render :partial => 'orders/orders', formats: [:json], handlers: [:jbuilder], locals: {orders: #orders} %>;
I have a weird problem where if an error is thrown in the jbuilder template, it renders a missing template error. so
If _orders.json.jbuilder looks like this
json.array! orders do |order|
json.someProperty order.a_missing_property
end
I get this:
ActionView::Template::Error (Missing partial orders/orders with {:locale=>[:en], :formats=>[:js, :html], :handlers=>[:erb, :builder, :coffee, :haml, :jbuilder, :riif]}
But if there is no error, this renders properly.
Any idea how my error is getting swallowed?
Update
I've created a demo app here: https://github.com/earnold/error-demo
If you load home/index you get a missing template error. If you comment out the bad line in the template, you render the template normally. What I am trying to do is make sure that errors aren't swallowed, but instead are shown on the page.

Answer 1

I was able to get an answer on Github here: https://github.com/rails/jbuilder/issues/40
Short version: this can be remedied by monkey patching Rails. Put this in an initializer and you're good to go.
if Rails.env.development? || Rails.env.staging?
module ActionView
class Template
protected
def handle_render_error(view, e) #:nodoc:
if e.is_a?(Template::Error)
e.sub_template_of(self)
raise e
else
assigns = view.respond_to?(:assigns) ? view.assigns : {}
template = self
unless template.source
# If an error occurs while the Jbuilder template is being rendered in
# in a nested context, you have a mismatch between the template format
# and the view context. Therefore, this block of code would raise
# a false exception (ActionView::MissingTemplate) and swallow the original
# error. This monkey patch tricks rails into thinking it was a json request
# so that refreshing the source hits the right partial
if template.formats == [:json]
view.lookup_context.formats = [:json]
end
template = refresh(view)
template.encode!
end
raise Template::Error.new(template, assigns, e)
end
end
end
end
end