fields_for sending array instead of Hash (Rails 3)

Question

I'm using fields_for in my form like so

<%= form_for @user %>
  ...
  <%= f.fields_for :photos do |f2| %>
    <%= f2.radio_button :public, 'true' %>
  <% end %>
  ...
<% end %>

Here are the radio buttons it generates:

<input id="user_photos_attributes_0_public_true" name="user[photos_attributes][0][public]" type="radio" value="true" /> 
<input id="user_photos_attributes_0_id" name="user[photos_attributes][0][id]" type="hidden" value="1" /> 

<input id="user_photos_attributes_1_public_true" name="user[photos_attributes][1][public]" type="radio" value="true" /> 
<input id="user_photos_attributes_1_id" name="user[photos_attributes][1][id]" type="hidden" value="4" /> 

<input id="user_photos_attributes_2_public_true" name="user[photos_attributes][2][public]" type="radio" value="true" /> 
<input id="user_photos_attributes_2_id" name="user[photos_attributes][2][id]" type="hidden" value="5" />
...

I have this in user.rb

  has_many :photos
  accepts_nested_attributes_for :photos

When form is submitted I get this error:

Error during failsafe response: ActionView::Template::Error
TypeError (expected Hash (got Array) for param `photos_attributes'):

Does anyone know why this is happening?

Btw, I'm using Rails 3.0.0.rc2

Answer 1

How are you saving your model?

If you inspect the params hash, you will get something like:

{ :user => {:photo_attributes => [{:id => 1, :public => true}, {:id => 4, :public => false}] }, :your_other_params => ... }}

So a User.new(params[:user]).save should work. Unless you are passing each hash of attributes instead of the array. See this article if you need a more in-depth detail.

What is in your params hash? That'd help you to trace the problem.

BTW, if you want a "true/false" behavior (I assume that because of the is_public property), rather than "present/non-present", a checkbox should be used. Radio buttons are for mutually exclusive options.