Nested input disappears when upgrading to activeadmin 1.0

Question

I have a form that, when maximally simplified, looks like this.

ActiveAdmin.register Foo do
  form do |f1|
    f1.inputs 'DeepFoos' do
      f1.has_many :deep_foos do |f2|
        f2.input :name

        f2.inputs "DeeperFoos for #{f2.object.name}" do
          f2.has_many :deeper_foos do |f3|
            f3.input :color
          end
        end
      end
    end
  end
end

When I was using activeadmin 0.6.6, this rendered fine, with the double-nested resource. After updating to 1.0.0.pre5, the DeeperFoos input part of the form disappeared. There's no exception, and it's not in the html source code of the page. It's simply gone.

Weirdly, if I remove the line that says f2.input :name, the DeeperFoos input rendered again.

I tried putting a debugger in it, and the debugger is hit, but the gem is so indirect and metaprogrammed that I don't know how I could possibly gain insight from it.

I can't find anything relevant in the activeadmin upgrade docs or the formtastic upgrade docs (which, as a dependency, got upgraded from 2.2.1 to 3.1.5).

Answer 1

This is probably due to the rewrite to integrate Arbre into forms. You are welcome to open a forms issue but I've given up for now on patching together Arbre, Formtasic and ActionView: as you have discovered it's ugly as they don't always share the same output buffers. ASFAIK relatively few try to use nested has_many. Can you move the input below inputs? Remove the blank line? It may just be a case of fiddling around and taking the best compromise.