Since after 87d1aba3c `dependent: :destroy` callbacks on has_one
assocations run *after* destroy, it is possible that a nullification is
attempted on an already destroyed target:
class Car < ActiveRecord::Base
has_one :engine, dependent: :nullify
end
class Engine < ActiveRecord::Base
belongs_to :car, dependent: :destroy
end
> car = Car.create!
> engine = Engine.create!(car: car)
> engine.destroy! # => ActiveRecord::ActiveRecordError: cannot update a
> destroyed record
In the above case, `engine.destroy!` deletes `engine` and *then* triggers the
deletion of `car`, which in turn triggers a nullification of `engine.car_id`.
However, `engine` is already destroyed at that point.
Fixes#21223.
As per the docs, `mark_for_destruction` should do nothing if `autosave`
is not set to true. We normally persist associations on a record no
matter what if the record is a new record, but we were always skipping
records which were `marked_for_destruction?`.
Fixes#20882
This code is so fucked. Things that cause this bug not to replicate:
- Defining the validation before the association (we end up calling
`uniq!` on the errors in the autosave validation)
- Adding `accepts_nested_attributes_for` (I have no clue why. The only
thing it does that should affect this is adds `autosave: true` to the
inverse reflection, and doing that manually doesn't fix this).
This solution is a hack, and I'm almost certain there's a better way to
go about it, but this shouldn't cause a huge hit on validation times,
and is the simplest way to get it done.
Fixes#20874.
These callbacks will already have been defined when the association was
built. The check against `reflection.autosave` happens at call time, not
at define time, so simply modifying the reflection is sufficient.
Fixes#18704
Before this commit, returning `false` in an ActiveRecord `before_` callback
such as `before_create` would halt the callback chain.
After this commit, the behavior is deprecated: will still work until
the next release of Rails but will also display a deprecation warning.
The preferred way to halt a callback chain is to explicitly `throw(:abort)`.
