CODEWITHSUNDEEP
ruby-on-railsactiverecord
pitosalas
pitosalas

Reputation: 10862

Why does this produce an infinite loop?

I am trying to assign a field in an ActiveRecord model (pos), to a value 1+ the highest value so far. The following, in either version, produces an infinite loop. I can't figure out why. Can you see it?

class Question < ActiveRecord::Base
  attr_accessible :text, :pos, :data_type, :active
  has_many :values
  belongs_to :program

  after_initialize :assign_pos

  def row_label
    text
  end

  def self.highest_pos
    self.order("pos DESC").first
  end

  def assign_pos
    puts "********* #{Question.highest_pos + 1}" # option 1
    self.pos = Question.highest_pos + 1 # option 2
  end

end

Upvotes: 0

Views: 267

Answers (2)

alestanis
alestanis

Reputation: 21863

Your assign_pos method is actually initializing self.pos, so because of the after_initialize condition, assign_pos gets called again, and initializes self.pos...

Upvotes: 2

Scott S
Scott S

Reputation: 2746

"self.order..." is actually selecting the object from the database, and calling initialize. After initialize it is calling assign_pos, which calls highest_pos, which starts everything all over again.

Upvotes: 1

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