What's This?

This is a stock Rails application designed to demonstrate a single case where validation failure handling does not match the documentation.

How To Reproduce The Issue

Don't forget to set up the app:

bundle install
rake db:migrate

In IRB:

Thing.create
Group.create
group = Group.first
group.update({'thing_ids' => ['1']})

The above will cause an ActiveRecord::RecordInvalid exception to be raised when update is called. According to the documentation, it should return false. This only occurs if the ThingGroupMembership fails to validate; the method correctly returns false if the Group doesn't pass validation instead.

How this app was created:

1. mkdir rails_validation_test
2. cd rails_validation_test
3. echo '2.4.1' > .ruby_version
4. echo '.gems' > .rbenv_gemsets
5. gem install bundler rails:4.2.8
6. rails new .
7. Create migration in db/migrate/20170515180342_make_entities.rb
8. Create model in app/models/group.rb
9. Create model in app/models/thing.rb
10. Create model in app/thing_group_memberships.rb
11. rake db:migrate