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Use of marked_for_destruction? in validation callback breaks autosave association behavior

#5041

I have a debate model, which should have at least 2 sides.
Here's some code:

has_many :sides, :dependent => :destroy
accepts_nested_attributes_for :sides, :allow_destroy => true
validate :has_enough_sides
# ...
def has_enough_sides
    unmarked_sides = sides.reject { |side| side.marked_for_destruction? }
    errors[:sides] << "A debate must have at least 2 sides." if unmarked_sides.size < 2
end

When I comment out "validate :has_enough_sides", changes are made to the nested sides when the debate model is updated with a nested form, as a normal nested form should. When I don't use the "marked_for_destruction?" function it also works fine.

However, when I include that validation, with the use of "marked_for_destruction?", all changes made to the nested models are ignored and no SQL is actually run, and the debate still saves and validates.

Oddly enough, if a side is invalid, the form is rendered again with the attributes of the original sides as if no changes were made.

I've looked through the source code and I'm pretty sure the problem is in here, but I cannot trace it: http://github.com/rails/rails/blob/76f024ac8db82490a99c71d0d8951d67...

Reported by Aaron Lifton · July 4th, 2010 @ 04:42 AM

Activity

Neeraj Singh
- Importance changed from to Low
ticket #4642 Unsaved changes to nested attribute collections are lost when using collection should have solved this problem.

July 7th, 2010 @ 07:38 PM

Neeraj Singh

I am not able to reproduce your case with rails edge. Here is my setup.

ActiveRecord::Schema.define(:version => 20100707175023) do

  create_table "questions", :force => true do |t|
    t.text    "name"
    t.integer "survey_id"
  end

  create_table "surveys", :force => true do |t|
    t.string "name"
  end

end
class Question < ActiveRecord::Base
  belongs_to :survey
end
class Survey < ActiveRecord::Base

  has_many :questions, :dependent => :destroy

  accepts_nested_attributes_for :questions, :allow_destroy => true

  validate :has_enough_questions

  def self.lab
    Survey.delete_all
    Question.delete_all
    survey = Survey.new(:name => 'cool_survey')
    q1 = survey.questions.build(:name => 'q1')
    q2 = survey.questions.build(:name => 'q2')
    survey.save!
    
    survey = Survey.first
    survey.update_attributes({:name => 'super_cool_survery', :questions_attributes => { '0' => {:id => q1.id.to_s, :name => 'q11'},
    '1' => {:id => q2.id.to_s, :name => 'q22'}}})
    puts survey.questions(true).inspect
  end

  private

  def has_enough_questions
    unmarked_questions = questions.reject { |q| q.marked_for_destruction? }
    errors[:questions] << "A survery must have at least 2 questions." if unmarked_questions.size < 2
  end

end

Just run Survey.lab and you will see the updated result. You can also see the sql statements for the update.

July 7th, 2010 @ 09:54 PM

Aaron Lifton
Great, thanks a lot for helping and trying to reproduce the error.

July 8th, 2010 @ 11:06 PM
Neeraj Singh
@Aaron Is your problem gone or are you still able to reproduce this on rails edge?

July 8th, 2010 @ 11:09 PM
Aaron Lifton
Well I was on Rails 3.0.0.beta4, I'll install rails edge and let you know.

July 11th, 2010 @ 05:20 PM

Subba

Assigned user set to Neeraj Singh

Neeraj,
i tried the above case it seems working for me also.
as you pointed out 4642 fixed this.



class Car < ActiveRecord::Base
  has_many :brakes
  accepts_nested_attributes_for :brakes, :allow_destroy => true
  validate :has_enough_brakes

  def has_enough_brakes
    unmarked_sides = brakes.reject { |side| side.marked_for_destruction? }
    if unmarked_sides.size < 2
      errors[:sides] << "A debate must have at least 2 sides."
    end
  end

  def self.lab
    car   = Car.new(:name => 'Toyota')
    car.brakes.build(:name => "middle")
    car.brakes.build(:name => "disc")
    car.save
    left  = car.brakes.create(:name => "left")
    car.update_attributes({
      :name => 'Toyota',
      :brakes_attributes => {
        "0" => {
          "name" => "right"
        },
        "1" =>{
          "id" => left.id.to_s,
          "_destroy" => "1"
        }
      }
    })
  end

end

July 16th, 2010 @ 09:29 PM

Neeraj Singh
- State changed from new to resolved
marking this ticket as resolved. If it is still an issue please report it and it can be reopened.

July 16th, 2010 @ 09:33 PM