Rails: Undefined method 'to_sym'

Question

I'm getting the following error in my deployed Rails 2.3.5 application:

NoMethodError (undefined method `to_sym' for nil:NilClass):

My local testing install of the application, which uses Sqlite, doesn't get the error, but my deployed app running Mysql does. The only other difference between the two is I'm running Ruby 1.8.7 on my local machine and 1.8.6 on my deployment server.

I've included the code from User.rb and the error log below. I set this up following the Declarative Authorization and Embedded Authorization Railscasts.

---

EDIT: Here's the code for the application_controller, where I set current_user using before_filter:

class ApplicationController < ActionController::Base
  helper :all
  helper_method :current_user_session, :current_user 
  before_filter :set_current_user

  protected 

  def set_current_user
    Authorization.current_user = current_user
  end

  def current_user_session  
    return @current_user_session if defined?(@current_user_session)  
    @current_user_session = UserSession.find  
  end  

  def current_user  
    @current_user = current_user_session && current_user_session.record  
  end
end

--

User.rb:

class User < ActiveRecord::Base
  acts_as_authentic 

  has_many :products
  has_many :transactions

  ROLES = %w[admin dmstaff staff faculty]

  def role_symbols
    [role.to_sym]
  end  

end

The error log:

NoMethodError (undefined method `to_sym' for nil:NilClass):
  app/models/user.rb:10:in `role_symbols'
  /usr/lib/ruby/gems/1.8/gems/declarative_authorization 0.4/lib/declarative_authorization/authorization.rb:242:in `roles_for'
  /usr/lib/ruby/gems/1.8/gems/declarative_authorization-0.4/lib/declarative_authorization/authorization.rb:296:in  `user_roles_privleges_from_options'
  /usr/lib/ruby/gems/1.8/gems/declarative_authorization-0.4/lib/declarative_authorization/authorization.rb:161:in `permit!'
  /usr/lib/ruby/gems/1.8/gems/declarative_authorization-0.4/lib/declarative_authorization/in_controller.rb:580:in `permit!'
  /usr/lib/ruby/gems/1.8/gems/declarative_authorization-0.4/lib/declarative_authorization/in_controller.rb:109:in `filter_access_filter'
  /usr/lib/ruby/gems/1.8/gems/declarative_authorization-0.4/lib/declarative_authorization/in_controller.rb:109:in `each'
  /usr/lib/ruby/gems/1.8/gems/declarative_authorization-0.4/lib/declarative_authorization/in_controller.rb:109:in `all?'
  /usr/lib/ruby/gems/1.8/gems/declarative_authorization-0.4/lib/declarative_authorization/in_controller.rb:109:in `filter_access_filter'
  passenger (2.2.5) lib/phusion_passenger/rack/request_handler.rb:95:in `process_request'
  passenger (2.2.5) lib/phusion_passenger/abstract_request_handler.rb:207:in `main_loop'
  passenger (2.2.5) lib/phusion_passenger/railz/application_spawner.rb:378:in `start_request_handler'
  passenger (2.2.5) lib/phusion_passenger/railz/application_spawner.rb:336:in `handle_spawn_application'
  passenger (2.2.5) lib/phusion_passenger/utils.rb:183:in `safe_fork'
  passenger (2.2.5) lib/phusion_passenger/railz/application_spawner.rb:334:in `handle_spawn_application'
  passenger (2.2.5) lib/phusion_passenger/abstract_server.rb:352:in `__send__'
  passenger (2.2.5) lib/phusion_passenger/abstract_server.rb:352:in `main_loop'
  passenger (2.2.5) lib/phusion_passenger/abstract_server.rb:196:in `start_synchronously'
  passenger (2.2.5) lib/phusion_passenger/abstract_server.rb:163:in `start'
  passenger (2.2.5) lib/phusion_passenger/railz/application_spawner.rb:213:in `start'
  passenger (2.2.5) lib/phusion_passenger/spawn_manager.rb:262:in `spawn_rails_application'
  passenger (2.2.5) lib/phusion_passenger/abstract_server_collection.rb:126:in `lookup_or_add'
  passenger (2.2.5) lib/phusion_passenger/spawn_manager.rb:256:in `spawn_rails_application'
  passenger (2.2.5) lib/phusion_passenger/abstract_server_collection.rb:80:in `synchronize'
  passenger (2.2.5) lib/phusion_passenger/abstract_server_collection.rb:79:in `synchronize'
  passenger (2.2.5) lib/phusion_passenger/spawn_manager.rb:255:in `spawn_rails_application'
  passenger (2.2.5) lib/phusion_passenger/spawn_manager.rb:154:in `spawn_application'
  passenger (2.2.5) lib/phusion_passenger/spawn_manager.rb:287:in `handle_spawn_application'
  passenger (2.2.5) lib/phusion_passenger/abstract_server.rb:352:in `__send__'
  passenger (2.2.5) lib/phusion_passenger/abstract_server.rb:352:in `main_loop'
  passenger (2.2.5) lib/phusion_passenger/abstract_server.rb:196:in `start_synchronously'

Rendering /var/data/app/current/public/500.html (500 Internal Server Error)

Answer 1

  def role_symbols
    [role.to_sym]
  end

-> role is Nil. Do you define role somewhere?

Answer 2

At some point, your code is expecting an object of type User, but is getting nil instead. Are you doing anything like this?

@user = User.find_by_login("Mary")
@user.role_symbols

Where, "Mary" is a nonexistent user login? Post any places where you are calling the role_symbols method and we can help more.

Edit: Looking at the method #roles_for here, without digging too deeply into that plugin, I'd say that #current_user is not set at this point of your code execution.