ActiverecordDeferPersist

• Add tests for a simple has_many association
• Support ActiveModel::Dirty so we can track changes association with team.user_ids_changed?
• wrap changes in a transaction

The default behavior of ActiveRecord is to persist the associated records immediately when you assign them, which can be surprising/dangerous. For example calling team.user_ids = [1, 2], or team.assign_attributes(params.permit(:user_ids)) will persist immediately.

This gem allows you to defer persisting to the database until the save method is called.

Inspiration for this gem goes to this gist by @sudoremo, thank you! There is an ongoing (may 2025) PR in Rails to add a defer option to has_many associations: rails/rails#55041

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

bundle add activerecord_defer_persist

  class Team < ApplicationRecord
    include ActiverecordDeferPersist

    has_many :users
    defer_persist :users
  end

  team = Team.new(user_ids: [])
  team.user_ids = [1, 2] # thid does not persist anymore !
  team.save # this will now persist

After checking out the repo, run bin/setup to install dependencies. 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.

VERSION=0.2.0 make deploy_gem

Bug reports and pull requests are welcome on GitHub at https://github.com/betagouv/activerecord_defer_persist.