Question

I’ve been getting the UnkownAttributeError for no particular reason, my models seem to be setup correctly…

School.rb

class School < ActiveRecord::Base
  attr_protected :id, :created_at, :updated_at

  #relationships
  has_many :users

  accepts_nested_attributes_for :users
end

My School model used to have the following, but it produced a MassAssignmentSecurity error for the user fields:

attr_accessible :country, :name, :state_or_province, :users_attributes

User.rb

class User < ActiveRecord::Base

  attr_accessible :email, :password, :password_confirmation, :remember_me, :username, :instructor_id, :first_name, :last_name, :school_id

  #relationships
  belongs_to :school

end

new.html.haml

= simple_form_for @school do |f|
  .well
    = f.input :name, :as => :hidden
    = f.input :country, :as => :hidden
    = f.input :state_or_province, :as => :hidden
  .well
    = f.simple_fields_for @school.users.build do |user_form|
      = user_form.input :first_name, :required => true
      = user_form.input :last_name, :required => true
      = user_form.input :username, :required => true
      ...
  = f.button :submit, "Next"

Note: @school is being populated in my new action from session information gathered on the previous page, I’m making a multi-step form. The school data is perfectly valid, if I was to remove the user form it would have no trouble saving the school.

The specific error message I’m getting in my create action:

ActiveRecord::UnknownAttributeError in SchoolsController#create

unknown attribute: user

And the sent params looks a little like this:

{“school”=>{“name”=>”Elmwood Elementary”, “country”=>”38”,
“state_or_province”=>”448”, “user”=>{“first_name”=>”joe”,
“last_name”=>”asdas”, “username”=>”asasdads”,
“email”=>”[e-mail]”, “password”=>”[FILTERED]”,
“password_confirmation”=>”[FILTERED]”}}, “commit”=>”Next”}

Is this maybe a bug with either Devise or simple_form? I’m using Rails 3.2.3

Answer 1

Ok, so apparently I needed to provide the symbol :users – the name of the relationship as my first argument for it to work.