Question

I am having trouble calling the methods generated by by my associations in my validations.

My code is pretty simple:

class Match < ActiveRecord::Base
  # Associations
  belongs_to :tournament

  has_many :match_player_relations
  has_many :waiting_players, through: :match_player_relations
  has_many :replays

  # Validations
  validates :tournament_id, presence: true
  validates :winner_id, inclusion: { in: waiting_players.map { |wp| wp.id } }
end

I have verified in my tests that there is a waiting_players method, and it works correctly. However, when I try to call it in my validations I get the following error:

/Users/max/.rvm/gems/ruby-1.9.3-p0/gems/activerecord-3.1.3/lib/active_record/base.rb:1088:in `method_missing': undefined local variable or method `waiting_players' for #<Class:0x007fc3b498c9c8> (NameError)
    from /Users/max/workplace/CloudLeagues/app/models/match.rb:11:in `<class:Match>'

Is there a way to solve this? Or do I need to remove the validation?

Answer 1

Pretty sure you need to pass a lambda to in to access the current record:

validates :winner_id, inclusion: { 
  in: lambda {|match| match.waiting_players.map { |wp| wp.id }}
}