errors.rb

should be valid
You have a nil object when you didn't expect it!
The error occurred while evaluating nil.support?
/Users/chrisadams/RailsApps/nag2/app/models/support.rb:10 :in `unique_parents?'
/Library/Ruby/Gems/1.8/gems/activesupport-2.3.2/lib/active_support/callbacks.rb:178 :in `send'
/Library/Ruby/Gems/1.8/gems/activesupport-2.3.2/lib/active_support/callbacks.rb:178 :in `evaluate_method'
/Library/Ruby/Gems/1.8/gems/activesupport-2.3.2/lib/active_support/callbacks.rb:166 :in `call'
/Library/Ruby/Gems/1.8/gems/activesupport-2.3.2/lib/active_support/callbacks.rb:90 :in `run'
/Library/Ruby/Gems/1.8/gems/activesupport-2.3.2/lib/active_support/callbacks.rb:90 :in `each'
/Library/Ruby/Gems/1.8/gems/activesupport-2.3.2/lib/active_support/callbacks.rb:90 :in `send'
/Library/Ruby/Gems/1.8/gems/activesupport-2.3.2/lib/active_support/callbacks.rb:90 :in `run'
/Library/Ruby/Gems/1.8/gems/activesupport-2.3.2/lib/active_support/callbacks.rb:276 :in `run_callbacks'
/Library/Ruby/Gems/1.8/gems/activerecord-2.3.2/lib/active_record/validations.rb:1033 :in `valid_without_callbacks?'
/Library/Ruby/Gems/1.8/gems/activerecord-2.3.2/lib/active_record/callbacks.rb:315 :in `valid?'
/Users/chrisadams/RailsApps/nag2/spec/models/support_spec.rb:7 
/tmp/textmate-command-7000.rb:3 
8  def unique_parents?
9    # if the support item with the same supportable and same user already exists, stop the creation
10    if self.user.support?(self)
11      errors.add(:user, "is already supporting this thought")
12    end

factories.rb

# User factories
Factory.define :user do |f|
  f.user_name             'nag-o-meter'
  f.first_name            'John'
  f.last_name             'Doe'
  f.dob                   Date.new(1982, 5, 11)
  f.sequence(:email)      {|n| "person#{n}@example.com" }
  f.password              'this_one_goes_to_eleven'
  f.password_confirmation { |u| u.password }
  f.accept_tos            '1'
  f.active                '1'
end

Factory.define :invalid_user, :parent => :user do |f|
  f.user_name             ''
end

# Thought factories
Factory.define :thought do |f|
  f.user_id       1
  f.association   :user
  f.thought_type  "idea"
  f.title         "The world is flat"
  f.description   "see friedman"
end

Factory.define :invalid_thought, :parent => :thought do |f|
  f.title            ''
end

# Support factories
Factory.define :support do |f|
  f.user_id        1
  f.association    :user
  f.supportable_id 2
  f.association    :supportable
end

Factory.define :invalid_support, :parent => :support do |f|
  f.user_id       ""
end

gistfile3.rb

require File.expand_path(File.dirname(__FILE__) + '/../spec_helper')

describe Support do

  it "should be valid" do
    @support = Support.new Factory.attributes_for(:support)
    @support.should be_valid
  end

end


describe Support, "Saying you'll do it on a thought" do
  
  it "shouldn't create a new support if one with the same parent user and parent thought already exists" do
    
    @user = Factory.create(:user)
    @thought = Factory.create(:thought)
    @support = Support.new Factory.attributes_for(:support) 
    @support.should be_valid
    @second_support = Support.new Factory.attributes_for(:support)
    @second_support.should_not be_valid

  end
  
end

gistfile4.rb

class Support < ActiveRecord::Base

  belongs_to :supportable, :polymorphic => true
  belongs_to :user

  validate_on_create :unique_parents?
  
  def unique_parents?
    # if the support item with the same supportable and same user already exists, stop the creation
    if self.user.support?(self)
      errors.add(:user, "is already supporting this thought")
    end

  end
end

gistfile5.rb

class User < ActiveRecord::Base

  authenticates_many :user_sessions
  acts_as_authentic do |c|
    c.validates_length_of_password_field_options = {:on => :update, :minimum => 4, :if => :has_no_credentials?}
    c.validates_length_of_password_confirmation_field_options = {:on => :update, :minimum => 4, :if => :has_no_credentials?}

    c.transition_from_crypto_providers = OldNagTransitionProvider
  end

  has_many :thoughts
  has_many :feedbacks
  has_many :actions
  has_many :suggestions
  has_many :comments

  has_many :intents, :conditions => { :completed => false }
  has_many :completed_intents, :conditions => { :completed => true }, :class_name => "Intent"
  has_many :intented_actions, :through => :intents, :source => :action
  has_many :completed_actions, :through => :completed_intents, :source => :action

  has_many :stories

  has_many :supports
  has_many :supported_actions, :through => :supports, :source => :supportable, :source_type => "Action"
  has_many :supported_feedbacks, :through => :supports, :source => :supportable, :source_type => "Feedback"
  has_many :supported_thoughts, :through => :supports, :source => :supportable, :source_type => "Thought"

  # the nag_tag sizes are used in the comments section
  # the comment size is used for when a user comments on their own actions/thoughts/feedback
  # the profile size is used when a user creates an action/thought/feedback item

  def self.curved_corner(px)
    "\\( +clone  -threshold -1 -draw 'fill black polygon 0,0 0,#{px} #{px},0 fill white circle #{px},#{px} #{px},0' \\( +clone -flip \\) -compose Multiply -composite \\( +clone -flop \\) -compose Multiply -composite \\) +matte -compose CopyOpacity -composite"
  end

  has_attached_file :avatar, 
    :whiny_thumbnails => true,
    :styles => {
      :nag_tag => { :format => :png, :geometry => "50x50#", :convert_options => curved_corner(5) },
      :comment  => { :format => :png, :geometry => "70x70#", :convert_options => curved_corner(10)},
      :profile => { :format => :png, :geometry => "100x100#", :convert_options => curved_corner(15)},
    },
    :url => "/system/:attachment/:id/:style/:basename.:extension",
    :path => ":rails_root/public/system/:attachment/:id/:style/:basename.:extension",
    :default_url => "/images/icons/missing_:style.png"

  attr_accessor :town, :postcode, :country
  attr_accessor :accept_tos

  # attr accessors are needed for the virtual attributes too
  attr_accessor :email_name, :email_domain 
  before_validation :populate_email 

  # activation support methods
  def active?
    active
  end

  def activate!
    update_attribute :active, true
  end

  def deliver_activation_instructions!
    reset_perishable_token!
    Notifications.deliver_activation_instructions(self)
  end

  def deliver_activation_confirmation!
    reset_perishable_token!
    Notifications.deliver_activation_confirmation(self)
  end

  def has_no_credentials?
    self.crypted_password.blank? && self.openid_identifier.blank?
  end

  def deliver_password_reset_instructions!  
    reset_perishable_token!
    Notifications.deliver_forgot_password(self)  
  end

  # needed for comatose admin to work
  attr_protected :admin, :active
  validates_presence_of :user_name, :message => "Don't forget your nag name!" 
  validates_presence_of :first_name, :message => "You need to add your first name."
  validates_presence_of :last_name, :message => "You need to add your last name."
  validates_presence_of :dob, :message => "Your date of birth is missing."
  validates_presence_of :email, :message => "Your email address is missing."
  validates_presence_of :password, :password_confirmation, :on => :create
  validates_acceptance_of :accept_tos, :message => "You'll need to accept the terms of service before you can start nagging"


  # Setter
  def populate_email
    unless @email_name.blank? and @email_domain.blank?
      write_attribute :email, [@email_name, '@', @email_domain].join('')
    end
  end 

  def activity(filter="", limit=70)
    ActivityCollator.for(self, filter, limit)
  end

  def does_or_did?(action)
    intented_actions.include?(action) or completed_actions.include?(action)
  end

  def support?(thing)
    supported_actions.include?(thing) or supported_feedbacks.include?(thing) or supported_thoughts.include?(thing)
  end

  def intent_for_action(action)
    intents.find_by_action_id action.id
  end


  # helpers for user migration from old nag
  def first_time_from_old_nag?
    from_old_nag? and not introduced_to_new_nag?
  end

  def introduce_to_new_nag
    update_attribute :introduced_to_new_nag, true
  end

  # hotness calcuations
  named_scope :hottest, :order => "hotness desc", :limit => 10

  def self.update_hotness
    find_each(&:update_hotness)
  end

  def update_hotness
    brand_new_hotness = [actions, thoughts, feedbacks].map { |c| c.sum(:hotness) }.sum
    update_attribute :hotness, brand_new_hotness
  end

end

thought.rb

class Thought < ActiveRecord::Base

  belongs_to :user

  has_many :comments, :as => :commentable
  has_many :pictures, :as => :imagable

  has_many :supports, :as => :supportable
  has_many :supporters, :through => :supports, :source => :user

  has_many :actions

  validates_presence_of :user_id, :title, :description, :thought_type