Template is missing error could be more helpful

I've been studying the problem.

It's only present in master, the thing is the find method ActionView::PathSet raise the ActionView::MissingTemplate with the "entries/edit - {:formats=>[:html], :locales=>[:en]} - partial: false.erb" string while the ActionView::MissingTemplate initializer expect only a path for the missing file, because of that the user see the ugly message of above.

The thing is that the details[:formats] is an array and I'm not sure if it does but can have more than one format and in this case we'll have to change the mensaje format in the initializer, provisionally I changed the rasing in the find to this:

  format = details[:formats].first.to_s
  raise ActionView::MissingTemplate.new(self, "#{prefix}/#{path}.#{format}")

But, I'm not sure if it's a rock solid solution.

new patch doing the same but without the format instance variable.

I'm not sure this approach will work - I think for the message to be effective, we want to know what content type / format the user is requesting.