Shopify's path to Rails 3 - Shopify

This post details the technical challenges and strategies employed by Shopify in upgrading their large, established Rails application to Rails 3. Key contributions include: the proactive use of Bundler for dependency management prior to the upgrade, a detailed process for migrating views and helpers to address XSS vulnerabilities ('safe by default'), the refactoring of a large number of routes using the new routing API, the process of updating internal and external libraries for Rails 3 compatibility, a solution for the 'helper :all' issue using `clear_helpers`, and the thorough testing of external service integrations. It also highlights the benefits of the upgrade, such as performance improvements and a cleaner API, and looks ahead to future Rails 3.x features.