When we work on Rails upgrades, most of the time we have to solve issues after updating the gems. These problems can go from simple and straightforward to really complex and hard to debug. Here we will discuss different skills and techniques that we use to complete the upgrade.

After upgrading your application from Rails 3 to Rails 4, you might start seeing the following deprecation warning if you are using the readonly option in an association.

DEPRECATION WARNING: The following options in your Company.has_many :users declaration are deprecated: :readonly. Please use a scope block instead. ...

In this blog post, we’ll discuss in detail what the readonly option is and how to handle the deprecation warning.

You might have extended classes or instances in Rails, but do you know you can also extend Rails associations?

class Account < ActiveRecord::Base
    has_many :people, -> { extending FindOrCreateByNameExtension }
end