Google Releases Official Rust Style Guide for Internal Projects

Google's New Rust Style Guide

Google has introduced an official style guide for the Rust programming language. This document provides guidelines for API and implementation design, extending beyond mere code formatting. The guide is specifically for internal use within Google.

Scope and Application

The style guide applies to Rust usage across various Google projects, including google3, Android, ChromeOS, Fuchsia, and Chrome. Its primary goal is to ensure consistency in Rust code both within individual codebases and across different projects at Google.

Rationale Behind the Guide

The motivation for creating this guide mirrors the reasons for Google's C++ style guide. Key objectives include improving code readability for long-term maintenance, facilitating large-scale code changes (LSCs), and establishing a standard of quality. The guide also seeks to reduce debate over stylistic choices during code reviews by providing clear rules.

Key Directives and Principles

The guide includes specific directives such as using `rust_library` for sources, importing items from one module per `use` statement, and preferring `expect` over `unwrap`. It also advises using `#[non_exhaustive]` for public enums and structs with public fields, and `#[must_use]` on functions and types. The guide states that official public Rust style rules should be followed unless they conflict with Google's specific guidance.