Can't destroy parent if not paranoid

[szechyjs]

If a parent model isn't paranoid it's impossible to destroy it. It calls #destroy on all the children, which doesn't actually delete them, then when it goes to delete the parent, it gets a foreign key violation from the database.

class Parent < ActiveRecord::Base
  has_many :children, dependent: :destroy
end

class Child < ActiveRecord::Base
  acts_as_paranoid

  belongs_to :parent
end

Parent.first.destroy

ActiveRecord::InvalidForeignKey: PG::ForeignKeyViolation: ERROR:  update or delete on table "parents" violates foreign key constraint "fk_rails_b38590a748" on table "children"
DETAIL:  Key (id)=(aa67c98c-d81f-5a9c-b0bc-26caa0051aea) is still referenced from table "children".

Since Parent is not paranoid I would expect calling #destroy to work and fully destroy its children.

If I add acts_as_paranoid to the parent it works just fine, however I have no need to soft delete the parent.

Originally posted by @szechyjs in #142 (comment)

[mvz]

This behavior is as intended. ActsAsParanoid aims to never allow accidental full destruction of a record. It cannot know that the destruction of Child objects is fine for you in this case.

The simplest solution for you would be to explicitly destroy the chidren with #destroy_fully before calling #destroy on the parent. This requires no change to ActsAsParanoid.

Going a bit further, I think there are three behaviors involving deletion of the Child that would be possible for a has_many/belongs_to relation (I'm leaving out the other options like nullify and restrict_with_error):

1. Fully destroy all children. This is what you're trying to achieve with dependent: :destroy.
2. Soft-delete all children. This is what actually happens with dependent: :destroy, but it's broken for your case since the foreign key is not nullified.
3. Delete the children from the database without any callbacks. This happens with dependent: :delete_all and may work for you depending on other factors.

It may be possible to add a mechanism to make case 1 work by adding some dependent: :destroy_fully option. Changing case 2 so that it works for all use cases is worth investigating but seems tricky.

[szechyjs]

I agree that case 1 would probably be the best fit here, as it would be opt-in (dependent: :destroy_fully).

[diegotc86]

Hi, I've been struggling with exactly this problem for a while. I finally solved it this way:

# Parent model
before_destroy do
    children.with_deleted.each(&:destroy_fully!)
end

You can leave the option dependent: :destroy or remove it. If you leave it, it first will make a soft delete on every child and then the before_destroy block will delete permanently the children.

Hope this is helpful for someone out there.

[mvz]

Hi @Atashia-Sameen that looks like a different problem since you're using dependent: :nullify inside Parent, instead of dependent: :destroy. Could you please open a new issue for this?