#4578 has_many association proxy delete method sometimes deletes too liberally - Ruby on Rails

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#4578 ✓invalid

has_many association proxy delete method sometimes deletes too liberally

Reported by Gabe da Silveira | May 11th, 2010 @ 10:32 PM

Really nasty bug bit me where I was doing something like this:

class Record < ActiveRecord::Base
  has_many :translations
end

...

record.translations.each do |translation|
  record.translations.delete(translation) if translation.is_bad?
end

if translation is a new record (ie. no id), then all new records would be deleted from the association.

this ticket is just a placeholder for now, I'll write up a failing test case and patch when I have some time.

Comments and changes to this ticket

Neeraj Singh May 12th, 2010 @ 03:46 AM
I am not able to reproduce this case with rails3 edge.
```
class Car < ActiveRecord::Base
  has_many :brakes

  def self.lab
    Car.create(:name => 'John')
    car = Car.last
    brakes = car.brakes
    brake = brakes.create(:name => 'wow')
    puts "brake id is #{brake.id}"
    brakes.build(:name => 'cursed brake')
    brakes.each do |brake|
      puts "processing brake #{brake.name}"
      car.brakes.delete(brake) 
    end
  end
end
```
The output of Car.lab is

SQL (0.4ms) INSERT INTO "cars" ("name") VALUES ('John')
Car Load (0.3ms) SELECT "cars". FROM "cars" ORDER BY cars.id DESC LIMIT 1 SQL (0.4ms) INSERT INTO "brakes" ("car_id", "name") VALUES (8, 'wow') brake id is 13
SQL (0.5ms) INSERT INTO "brakes" ("car_id", "name") VALUES (8, 'airblad') Brake Load (0.3ms) SELECT "brakes". FROM "brakes" WHERE ("brakes".car_id = 8) processing brake wow
SQL (0.3ms) UPDATE "brakes" SET "car_id" = NULL WHERE ("brakes"."car_id" = 8 AND "brakes"."id" IN (13)) processing brake cursed brake
=> [#]

Everything looks okay to me.
Ryan Bigg May 13th, 2010 @ 11:48 PM
- Tag changed from “activerecord associations” to “activerecord associations, bugmash”
- State changed from “new” to “incomplete”
Please provide a failing test case and patch for this issue.
Neeraj Singh July 15th, 2010 @ 03:15 AM
- Importance changed from “” to “Low”
@Gabe Let's say that I have added a new record to collection using build. Now I want to delete that record. All I have to do is collection.delete(record) and then new object previously added to collection gets deleted. This behavior looks okay to me.

If your proposal is accepted then how would anyone delete any new record from collection?
You flagged this item as spam.
Gabe da Silveira July 15th, 2010 @ 03:25 AM
Actually I wasn't proposing anything, what I was experiencing was a straight-up bug. However, I eventually tracked this down to a condition in my application, so there is in fact no bug here. Please make this ticket invalid.
Neeraj Singh July 15th, 2010 @ 03:30 AM
- State changed from “incomplete” to “invalid”
Rohit Arondekar October 7th, 2010 @ 05:21 AM
- Tag changed from “activerecord associations, bugmash” to “activerecord, associations, bugmash”
[bulk edit]