# dependent-auto-rails

This gem provides a new `dependent` option for ActiveRecord associations, `:auto`. Using this option will automatically select between `:destroy` and `:delete` / `:delete_all` during runtime based on whether or not the associated model has any destroy callbacks defined. This is useful since `dependent: :destroy` always initialises the associated records in order to execute their destroy callbacks regardless of whether or not there are any defined. This can be expensive if there are many records to destroy.

It is also useful since a model's associations are rarely updated, but it's business logic can change frequently. This means that if destroy callbacks are added or removed on the associated model, the `dependent` option on the parent model's association may need to be updated to reflect this. Using `dependent: :auto` will automatically select the appropriate `dependent` option based on the current state of the model.

**NOTE**: The `:auto` option **ONLY** decides between `:destroy` and `:delete` / `:delete_all`. It does not support any other `dependent` options such as:
- `:nullify`
- `:destroy_async`
- `:restrict_with_error`
- `:restrict_with_exception`

**NOTE**: If for some reason the `:auto` option is unable to decide between `:destroy` and `:delete` / `:delete_all`, it will default to `:destroy`.

## Installation

Install the gem and add it to the application's Gemfile by executing:

    $ bundle add dependent-auto-rails

If bundler is not being used to manage dependencies, install the gem by executing:

    $ gem installdependent-auto-rails

## Usage

To use this gem, all you need to do is add `dependent: :auto` to your model associations where you would usually use one of:
 - `dependent: :destroy` (`belongs_to`, `has_one`, `has_many`)
 - `dependent: :delete` (`belongs_to`, `has_one`)
 - `dependent: :delete_all` (`has_many`).

```ruby
class Post < ApplicationRecord
  belongs_to :author, dependent: :auto

  has_one :pinned_comment, dependent: :auto

  has_many :comments, dependent: :auto
end

```

## Development

After checking out the repo, run `bin/setup` to install dependencies. Then, run `rake test` to run the tests. You can also run `bin/console` for an interactive prompt that will allow you to experiment.

To install this gem onto your local machine, run `bundle exec rake install`. To release a new version, update the version number in `version.rb`, and then run `bundle exec rake release`, which will create a git tag for the version, push git commits and the created tag, and push the `.gem` file to [rubygems.org](https://rubygems.org).

## Contributing

Bug reports and pull requests are welcome on GitHub at https://github.com/joshuay03/dependent-auto-rails. This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the [code of conduct](https://github.com/[USERNAME]/dependent-auto-rails/blob/main/CODE_OF_CONDUCT.md).

## License

The gem is available as open source under the terms of the [MIT License](https://opensource.org/licenses/MIT).

## Code of Conduct

Everyone interacting in the Dependent::Auto::Rails project's codebases, issue trackers, chat rooms and mailing lists is expected to follow the [code of conduct](https://github.com/[USERNAME]/dependent-auto-rails/blob/main/CODE_OF_CONDUCT.md).