Software Engineering at Google

Chapter 19. Critique: Google’s Code Review Tool

Written by Caitlin Sadowski, Ilham Kurnia, and Ben Rohlfs

Edited by Lisa Carey

As you saw in Chapter 9, code review is a vital part of software development, particularly when working at scale. The main goal of code review is to improve the readability and maintainability of the code base, and this is supported fundamentally by the review process. However, having a well-defined code review process in only one part of the code review story. Tooling that supports that process also plays an important part in its success.

In this chapter, we’ll look at what makes successful code review tooling via Google’s well-loved in-house system, Critique. Critique has explicit support for the primary motivations of code review, providing reviewers and authors with a view of the review and ability to comment on the change. Critique also has support for gatekeeping what code is checked into the codebase, discussed in the section on “scoring” changes. Code review information from Critique also can be useful when doing code archaeology, following some technical decisions that are explained in code review interactions (e.g., when inline comments are lacking). Although Critique is not the only code review tool used at Google, it is the most popular one by a large margin.

Code Review Tooling Principles

We mentioned above that Critique provides functionality to support the goals of code review (we look at this functionality in more detail later in this ...