Nested sign up form does not display the error messages for the nested object

Question

Organization and User have a many-to-many relationship through Relationship. There's a joined signup form. The sign up form works in that valid information is saved while if there's invalid information it rolls back everything.

The problem is that the form does not display the error messages for the nested User object. Errors for Organization are displayed, the form correctly re-renders if there are errors for User, but the errors for User are not displayed.

Why are the errors when submitting invalid information for users not displayed? Any help is appreciated.

---

The signup form/view:

<%= form_for @organization, url: next_url do |f| %>
  <%= render partial: 'shared/error_messages', locals: { object: f.object, nested_models: f.object.users } %>
  ... fields for organization...
  <%= f.fields_for :users do |p| %>
    ...fields for users...
  <% end %>
  <%= f.submit "Register" %>
<% end %>

The shared error messages partial:

<% if object.errors.any? %>
  <div id="error_explanation">
    <div class="alert alert-danger">
      The form contains <%= pluralize(object.errors.count, "error") %>.
    </div>
    <ul>
      <% object.errors.full_messages.each do |msg| %>
        <li><%= msg %></li>
      <% end %>
    </ul>
  </div>
<% end %>

<% if defined?(nested_models) && nested_models.any? %>
  <div id="error_explanation">
    <ul>
      <% nested_models.each do |nested_model| %>
        <% if nested_model.errors.any? %>
          <ul>
            <% nested_model.errors.full_messages.each do |msg| %>
              <li><%= msg %></li>
            <% end %>
          </ul>
        <% end %>
      <% end %>
    </ul>
  </div>
<% end %>

The controller method:

def new
  @organization = Organization.new
  @user = @organization.users.build
end

def create
  @organization = Organization.new(new_params.except(:users_attributes))
  @organization.transaction do
      if @organization.valid?
        @organization.save
        begin
          @user = @organization.users.create!(users_attributes)
          @relationship = @organization.relationships.where(user: @user).first
          @relationship.update_attributes!(member: true, moderator: true)
        rescue
          raise ActiveRecord::Rollback
        end
      end
  end
  if @organization.persisted?
      if @organization.relationships.where('member = ? ', true).any?
        @organization.users.where('member = ? ', true).each do |single_user|
          single_user.send_activation_email
        end
      end
      flash[:success] = "A confirmation email is sent."
      redirect_to root_url
  else
    @user = @organization.users.build(users_attributes) if @organization.users.blank?
    render :new
  end
end

The Organization model:

has_many :relationships, dependent: :destroy
has_many :users, through: :relationships, inverse_of: :organizations

accepts_nested_attributes_for :users, :reject_if => :all_blank, :allow_destroy => true
validates_associated :users

The Relationship model:

belongs_to :organization
belongs_to :user

The User model:

has_many :relationships, dependent: :destroy 
has_many :organizations, through: :relationships, inverse_of: :users

Update: If I add an additional line to def create as below, it seems to work, i.e., then it does display the error messages. However, then it for some reason doesn't save when valid information is submitted. Any ideas how to deal with that?

def create
  @organization = Organization.new(new_params.except(:users_attributes))
  @user = @organization.users.new(users_attributes)
  @organization.transaction do
    ...

Answer 1

In case someone might be looking for a solution to render form errors in a form, try:

f.object.errors["account.address"].present?`

The address is the nested attribute here.

Answer 2

I had a similar problem. everything seemed to work fine, but I was not getting any errors The solution i found is to build the comment in article#show instead of the view:

@article = Article.find(params[:id])
@comment = @article.comments.build(params[:comment])

and in your articles#show don't use @article.comments.build but @comment:

<%= form_for([@article, @comment]) do |f| %>
   <%= render 'shared/error_messages', :object => f.object %>
   <p><%= f.submit %></p>
<% end %>

make sure you build the comment in your comment#create as well (you really have no choice though :P)

I think you need to pass f.object instead of @comment.

Answer 3

This is classic use case for form objects. It is convenient from many perpectives (testing, maintainance ...). For example:

class Forms::Registration
  extend ActiveModel::Naming
  include ActiveModel::Conversion
  include ActiveModel::Validations

  def persisted?
    false
  end

  def initialize(attributes = {})
    %w(name other_attributes).each do |attribute|
      send("#{attribute}=", attributes[attribute])
    end
  end

  validates :name, presence: true

  validate do
    [user, organization].each do |object|
      unless object.valid?
        object.errors.each do |key, values|
          errors[key] = values
        end
      end
    end
  end

  def user
    @user ||= User.new
  end

  def organization
    @organization ||= Organization.new
  end

  def save
    return false unless valid?
    if create_objects
      # after saving business logic
    else
      false
    end
  end

  private
  def create_objects
    ActiveRecord::Base.transaction do
      user.save!
      organization.save!
    end
  rescue
    false
  end
end

the controller:

class RegistrationsController < ApplicationController
  def new
    @registration = Forms::Registration.new
  end

  def create
    @registration = Forms::Registration.new params[:registration]
    if @registration.save
      redirect_to root_path
    else
      render action: :new
    end
  end
end

and the view in HAML:

= form_for @registration, url: registrations_path, as: :registration do |f|
  = f.error_messages
  = f.label :name
  = f.text_field :name

  = f.submit

It is worth to read more about form objects.

Answer 4

Maybe try this:

  <%= render partial: 'shared/error_messages',
       locals: { object: f.object, nested_models: [ @user ] } %>

I guess the call to @organization.users.blank? doesn't work in the way you expected it to do, as the user is not correctly created, because #create! threw an exeption. Rails probably does a check on the database, to see if there are any users now, and thinks there is still nothing in there. So your @organization.users.build(users_attributes) gets called, but this doesn't trigger validation.

In general I would also recommend you the use of a form object (like in the other answer), when creating complex forms, as this clarifies things like that and makes the view more clean.

Answer 5

Nested attributes bit me SOOO hard every time I decided it's a good time to use them, and I see you know a bit of what I'm talking about.

Here's a suggestion of a different approach, use a form object instead of nested attributes: http://blog.codeclimate.com/blog/2012/10/17/7-ways-to-decompose-fat-activerecord-models/ see under section 3. Extract Form Objects

You can extract your existing validations on the User model into a module and import that, to expand on the solution from the blog:

https://gist.github.com/bbozo/50f8638787d6eb63aff4

With this approach you can make your controller code super-simple and make simple and fast unit tests of the not-so-simple logic that you implemented inside and save yourself from writing integration tests to test out all different possible scenarios.

Also, you might find out that a bunch of the validations in the user model are actually only within the concern of the signup form and that those validations will come and bite in later complex forms, especially if you're importing data from a legacy application where validations weren't so strict, or when you one day add additional validators and make half of your user records invalid for update.