I'm having difficulty saving two fields in a nested form. The parent field saves fine, but the nested field is throwing the "WARNING: Can't mass-assign protected attributes" error.

I've placed things in the Item model with attr_accessible, but it's not solving the issue.

List_controller

def create
  @list = List.new(params[:list])
  @list[:user_id] = current_user.id
  if @list.save
    flash[:notice] = "Successfully created list."
    redirect_to @list
  else
    render :action => 'new'
  end
end

List model

class List < ActiveRecord::Base
  has_many :items, :dependent => :destroy
  accepts_nested_attributes_for :items, :reject_if => lambda { |a| a[:name].blank? },     :allow_destroy => true
end

Item model

class Item < ActiveRecord::Base
  belongs_to :list
end

Form

<%= form_for(@list) do |list_form| %>

  <p>
    <%= list_form.label :title %><br />
    <%= list_form.text_field :title %>
  </p>

  <p>
 开发者_Go百科 <%= render :partial => 'item_fields',
         :locals => {:form => list_form} %>
  </p>

  <%= list_form.submit %>
<% end %>

Form partial

<%= form.fields_for :item do |item_form| %>
    <%= item_form.label :name, 'item' %>
    <%= item_form.text_field :name %>
<% end %>

Server error log

Started POST "/lists" for 127.0.0.1 at Sun Mar 27 02:54:18 -0400 2011
  Processing by ListsController#create as HTML
  Parameters: {"commit"=>"Create List", "list"=>{"title"=>"figaro", "item"=>{"na
me"=>"foobar"}}, "authenticity_token"=>"afu5xPgvJenu6XKXcsyilR8RconLP/OZ3NxsICE3RVk=
", "utf8"=>"Γ£ô"}
  ←[1m←[35mUser Load (1.0ms)←[0m  SELECT "users".* FROM "users" WHERE "users"."i
d" = 2 LIMIT 1


WARNING: Can't mass-assign protected attributes: item


  ←[1m←[36mAREL (2.0ms)←[0m  ←[1mINSERT INTO "lists" ("user_id", "updated_at", "
title", "created_at") VALUES (2, '2011-03-27 06:54:18.893302', 'figaro', '2011-0
3-27 06:54:18.893302')←[0m
Redirected to http://localhost:3000/lists/77
Completed 302 Found in 117ms

You're using fields_for :item but your List model has_many :items.

Try this:

<%= form.fields_for :items do |item_form| %>

If this doesn't help try to add attr_accessible :items_attributes to you List model. From the docs:

[..] If you are using attr_protected or attr_accessible, then you will need to add the attribute writer to the allowed list.

Add attr_accessible :items to your List class.