At FastRuby.io we love Ruby on Rails because it is so powerful: You can quickly create an application that is feature complete, stable, and secure

Unfortunately, maintaining a Rails application up to date and secure takes some effort.

In this blog post, we will cover a few Ruby gems and best practices that you can use to stay on top of your security, reliability, and stability needs.

Have you ever tried to update a Rails app from 5.2 to 6.0, or from 6.0 to 6.1? If so, you might have seen this deprecation:

DEPRECATION WARNING: Dangerous query method (method whose arguments are used as raw SQL) called with non-attribute argument(s): "random()". Non-attribute arguments will be disallowed in Rails 6.0. This method should not be called with user-provided values, such as request parameters or model attributes. Known-safe values can be passed by wrapping them in Arel.sql(). (called from ...)

Note: While this deprecation message mentions Rails 6.0 as the version where the behavior is disallowed, that change was postponed, so the deprecation also shows in Rails 6.0. The behavior is actually disallowed in Rails 6.1.

What does this deprecation mean exactly? In this article, I will explain that in plain English, what issue it is trying to prevent, and how to fix the problem if you come across it in your codebase.