How to Automate Your Coding Style? A Short Guide to Code Formatting, Pre-commit and CI

Code serves as communication between developers. While we use programming languages to instruct computers, code also communicates with colleagues - both present and future team members. This guide explores automating code formatting and styling checks to improve clarity.

As Robert C. Martin notes in Clean Code, code is read far more often than written, with a ratio exceeding 10 to 1. Improving readability directly enhances maintainability, speeds onboarding, prevents code degradation, and simplifies development work overall.

The guide demonstrates using Black, an open-source Python formatter, for automated code styling. Installation is straightforward via pip, and basic usage requires a single command to format an entire directory.

Pre-commit, a framework for managing Git hooks, automates formatting checks before commits. After installation and configuration, developers can establish consistent standards across their team. The framework is language-agnostic and works across different project types.

When attempting to commit unformatted code, pre-commit triggers an error and automatically formats the files. A second commit attempt succeeds with the properly formatted code.

For additional enforcement, Continuous Integration pipelines can run pre-commit checks during merge requests, preventing poorly formatted code from reaching main branches.

A practical consideration: repository-wide formatting commits obscure change history in git blame. Git 2.23+ supports ignoring specific commits through .git-blame-ignore-revs files, preserving accurate attribution history.