CI Integration

cmakefmt is designed to be a zero-friction CI step. Use --check to fail the build when files are not formatted, or --in-place to auto-format and commit the result.

GitHub Actions

The official cmakefmt/cmakefmt-action installs the right binary for the runner OS and adds it to PATH. No Rust toolchain required.

Check mode (recommended)

Fail the workflow if any CMake files are not formatted:

- uses: cmakefmt/cmakefmt-action@v1
  with:
    args: '--check .'

Auto-format

Format files in-place. Combine with a commit step to push the changes automatically:

- uses: cmakefmt/cmakefmt-action@v1
  with:
    args: '--in-place .'

Install only

Install cmakefmt without running it, then call it yourself with custom flags:

- uses: cmakefmt/cmakefmt-action@v1
  with:
    args: ''

- run: cmakefmt --check --report-format github .

Pin a specific version

- uses: cmakefmt/cmakefmt-action@v1
  with:
    version: '0.2.0'
    args: '--check .'

Full example

name: Format check

on: [push, pull_request]

jobs:
  cmakefmt:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd  # v6.0.2
      - uses: cmakefmt/cmakefmt-action@v1
        with:
          args: '--check .'

GitLab CI

Download the pre-built Linux binary directly from GitHub Releases:

cmakefmt:
  stage: lint
  image: ubuntu:latest
  before_script:
    - apt-get update -qq && apt-get install -y -qq curl
    - |
      LATEST=$(curl -sI https://github.com/cmakefmt/cmakefmt/releases/latest \
        | grep -i '^location:' \
        | sed 's|.*/tag/v||;s/[[:space:]]//g')
      curl -sSL \
        "https://github.com/cmakefmt/cmakefmt/releases/download/v${LATEST}/cmakefmt-x86_64-unknown-linux-musl.tar.gz" \
        | tar -xz -C /usr/local/bin
  script:
    - cmakefmt --check .

Or install via Cargo if you already have a Rust image:

cmakefmt:
  stage: lint
  image: rust:latest
  cache:
    paths:
      - $CARGO_HOME/bin/
  script:
    - cargo install cmakefmt-rust --quiet
    - cmakefmt --check .

pre-commit

Add a local hook to your .pre-commit-config.yaml. This runs cmakefmt --check on every staged CMake file before the commit is created:

repos:
  - repo: local
    hooks:
      - id: cmakefmt
        name: cmakefmt
        language: system
        entry: cmakefmt --check
        files: '(CMakeLists\.txt|\.cmake)$'
        pass_filenames: true

Install the hook once per clone:

pre-commit install

You can also run it manually across all files:

pre-commit run cmakefmt --all-files

Check only changed files

When working on large repositories, limit formatting checks to files changed since a given ref to keep CI fast:

# Check files changed since the last tag
cmakefmt --check --changed v0.1.0

# Check only staged files (useful locally)
cmakefmt --check --staged