Question

I’m currently reading Rails 3 In Action. The book creates an app where one can create Projects and for each Project on can create Tickets. It creates 3 models:

Project:

    class Project < ActiveRecord::Base
      attr_accessible :name
      validates :name, presence: true
      has_many :tickets, :dependent => :destroy
    end

Ticket:

    class Ticket < ActiveRecord::Base
      belongs_to :project
      belongs_to :user
      attr_accessible :description, :title
      validates :title, presence: true
      validates :description, presence: true, :length => { :minimum => 10 }
    end

and User:

    class User < ActiveRecord::Base
      devise :database_authenticatable, :registerable, :confirmable,
             :recoverable, :rememberable, :trackable, :validatable
      attr_accessible :email, :password, :password_confirmation, :remember_me
    end

Now when I add the following line to the create action inside the tickets_controller:

    @ticket = @project.tickets.build(params[:ticket].merge!(:user => current_user))

I get this error Can't mass-assign protected attributes: user. Now I don’t really understand what merge! is doing and why :user is being passed in or why I’m getting the error. I know that normally I would have to include the mass-assignment attribute to the attr_accessible: method. But this time the attribute is a class so I don’t know how to handle this.

help,
mike

Answer 1

@ticket = @project.tickets.build(params[:ticket])
@ticket.user = current_user

Unless there’s a reason why you need this on a single line? In which case maybe

@ticket = @project.tickets.build(params[:ticket].merge!(:user_id => current_user.id))