cmakefmt 1.2.0

A fast, correct CMake formatter

cmakefmt

^CI
   

^Package
 

^{Security & Quality}
  

A lightning-fast, workflow-first CMake formatter — built in Rust, built to last.

The above demo was generated with VHS.

cmakefmt replaces the aging Python cmake-format tool with a single native binary. Same spirit. No Python.

• crates.io: cmakefmt-rust
• CLI name: cmakefmt

[!NOTE]

This project is independent from other Rust implementations, including: azais-corentin/cmakefmt and yamadapc/cmakefmt.

Contents

• Why cmakefmt?
• Performance
• Installation
• Quick Start
• Common Workflows
• Configuration
• Formatter Disable Regions
• Library Usage
• Documentation
• Project Layout
• Development
• Status
• License

Why cmakefmt?

• 104× faster — not a typo. Geometric-mean speedup of 104× over cmake-format on real-world per-file corpora, rising to 2,853× on whole-repository runs. Pre-commit hooks that once made you wince now finish before you blink.
• Zero dependencies. One binary. No Python environment, no virtualenv bootstrap, no dependency drift. Drop it in CI and forget about it.
• Built for actual workflows. --check, --diff, --staged, --changed, --files-from, --show-config, --explain-config, semantic verification, JSON reporting — all first-class, not scripted workarounds.
• Knows your commands. Teach cmakefmt the argument structure of your project's custom CMake functions and macros. No more generic token-wrapping for code you wrote.
• Errors that actually help. Parse and config failures come with file/line context, source snippets, and reproduction hints — not opaque parser noise.
• Designed for real repositories. Comment preservation, disable-region passthrough, config discovery, ignore files, Git-aware file selection, and opt-in parallelism are core features, not afterthoughts.

Performance

Fixture	Lines	cmakefmt ms	cmake-format ms	Speedup
opencv_flann/CMakeLists.txt	2	6.3	55.8	8.9×
googletest/CMakeLists.txt	36	5.4	68.2	12.6×
llvm_tablegen/CMakeLists.txt	83	6.4	83.8	13.1×
abseil/CMakeLists.txt	280	6.8	186.1	27.4×
spdlog/CMakeLists.txt	413	7.7	239.1	31.1×
mariadb_server/CMakeLists.txt	656	7.1	532.0	75.0×
xnnpack/CMakeLists.txt	1,354	8.6	1,568.9	182.2×
opencv/CMakeLists.txt (root)	2,039	9.8	43,158.4	4,417.2×
blender/CMakeLists.txt (root)	2,650	8.6	2,922.7	338.5×
llvm/libc/.../CMakeLists.txt	6,688	8.9	2,473.7	279.3×
grpc/CMakeLists.txt (root)	54,834	39.4	84,489.2	2,146.2×

Geometric-mean per-file speedup: 104×. Whole-repository parallel runs (across 14 large open-source repos including LLVM, blender, opencv, gRPC, and oomph-lib) average 150× faster than cmake-format geo-mean (95× serial), with parallel mode delivering up to 2.9× over cmakefmt serial on large repositories.

Full methodology and profiler notes: cmakefmt.dev/performance/.

Update the pinned local corpus and generate local before/after review artifacts with:

python3 scripts/fetch-real-world-corpus.py
scripts/review-real-world-corpus.sh

Installation

Homebrew (macOS):

brew install cmakefmt/cmakefmt/cmakefmt

Cargo (any platform):

cargo install cmakefmt-rust

pip (any platform with Python):

pip install cmakefmt

conda-forge:

conda install -c conda-forge cmakefmt

Pre-built binaries (Linux, macOS, and Windows):

Download the .zip / .tar.gz for your platform from GitHub Releases, extract, and place the binary on your PATH.

Build from source:

git clone https://github.com/cmakefmt/cmakefmt
cd cmakefmt
cargo install --path .

Verify:

cmakefmt --version

Release channels and support levels are documented at cmakefmt.dev/release/. Shell completion installation instructions are available at cmakefmt.dev/install/.

Quick Start

cmakefmt config init               # generate a starter .cmakefmt.yaml
cmakefmt --check .                 # dry-run: just show which files would change
cmakefmt .                         # dry-run: preview formatted output; changed lines shown in blue
cmakefmt --diff .                  # dry-run: view a unified diff of what would change (like `git diff`)
cmakefmt --in-place .              # apply formatting across the whole project
cmakefmt --staged --check          # use in pre-commit hooks
cmakefmt --path-regex 'src/.*' .   # format CMake files only under src/

Common Workflows

Task	Command
Format file to stdout	cmakefmt CMakeLists.txt
Rewrite files in place	cmakefmt --in-place .
CI check	cmakefmt --check .
Preview which files would change	cmakefmt --list-changed-files .
See the exact patch	cmakefmt --diff CMakeLists.txt
Verify semantics while formatting to stdout	cmakefmt --verify CMakeLists.txt
Pre-commit guard (staged files only)	cmakefmt --staged --check
PR-scoped check	cmakefmt --changed --since origin/main --check
Machine-readable CI output	cmakefmt --check --report-format json .
GitHub Actions annotations	cmakefmt --check --report-format github .
Checkstyle / JUnit / SARIF output	cmakefmt --check --report-format checkstyle .
Pin the required binary version in CI	cmakefmt --required-version 1.2.0 --check .
Speed up repeated large-repo checks	cmakefmt --cache --check .
Roll out formatting file-by-file	cmakefmt --require-pragma --check .
Find project-specific commands	cmakefmt --list-unknown-commands .
Watch and auto-format on save	cmakefmt --watch .
Explain formatting decisions	cmakefmt --explain CMakeLists.txt
Read from stdin	cat CMakeLists.txt | cmakefmt -

Configuration

cmakefmt searches upward from each file for .cmakefmt.yaml, .cmakefmt.yml, or .cmakefmt.toml. YAML is recommended for larger configs.

Example .cmakefmt.yaml:

format:
  line_width: 100
  tab_size: 4

style:
  command_case: lower
  keyword_case: upper

markup:
  enable_markup: true

Debug which config a file is actually using:

cmakefmt --show-config-path src/CMakeLists.txt
cmakefmt --show-config src/CMakeLists.txt
cmakefmt --explain-config

Migrate from an existing cmake-format config:

cmakefmt --convert-legacy-config .cmake-format.py > .cmakefmt.yaml

Full config reference: cmakefmt.dev/config/.

Formatter Disable Regions

Selectively opt out of formatting with barrier comments.

There are three barrier styles:

1. Legacy cmake-format directives:

   # cmake-format: off
   set(MESSY_THING  a   b   c)   # kept verbatim
   # cmake-format: on
   

2. Native directive barriers, using either cmakefmt or the shorter fmt spelling:

   # cmakefmt: off
   set(MESSY_THING  a   b   c)   # kept verbatim
   # cmakefmt: on
   
   # fmt: off
   set(MESSY_THING  a   b   c)   # kept verbatim
   # fmt: on
   

3. Fence barriers, which toggle formatting on and off each time # ~~~ appears:

   # ~~~
   set(MESSY_THING  a   b   c)   # kept verbatim
   # ~~~
   

Use directive barriers when you want an explicit start/end marker, and fence barriers when you want a shorter toggle-style block.

Library Usage

cmakefmt is also available as a Rust library:

use cmakefmt::{format_source, Config};

fn main() -> Result<(), cmakefmt::Error> {
    let src = r#"target_link_libraries(foo PUBLIC bar baz)"#;
    let out = format_source(src, &Config::default())?;
    println!("{out}");
    Ok(())
}

Full API docs: cmakefmt.dev/api/.

Documentation

Start here: https://cmakefmt.dev.

Doc	Description
Install	Install options, first-project setup, CI wiring
Coverage	How coverage is measured, published, and interpreted
Release Channels	Release contract, support levels, and release artifacts
CLI Reference	Every flag, exit code, and discovery rule
Config Reference	Full config schema with examples
Formatter Behavior	How the formatter makes layout decisions
Migration from cmake-format	Incremental rollout guide and CLI mapping
Library API	Embedding cmakefmt in your own Rust tools
Troubleshooting	Common issues and debug workflow
Performance	Benchmark methodology and profiler notes
Contributing	How to contribute, run tests, and open PRs
Changelog	What's changed in each release

Preview the full docs locally:

cd docs && npm install && npm run dev

Project Layout

cmakefmt/
├── docs/        # Astro + Starlight source published to cmakefmt.dev
├── src/         # CLI, library API, parser, config, spec, formatter
├── tests/       # integration tests, snapshots, and fixtures
├── benches/     # Criterion benchmarks
├── scripts/     # repo maintenance and docs helpers
└── .github/     # CI and Pages workflows

Key modules under src/:

• main.rs: CLI entry point and workflow orchestration
• lib.rs: public library API
• config/: config loading, merging, and legacy conversion
• parser/: hand-written parser, AST, and lowering pipeline
• spec/: built-in and user-defined command registry
• formatter/: AST-to-doc formatting logic and comment handling
• files.rs: file discovery and ignore handling

Development

cargo fmt --check                          # formatting
cargo clippy --all-targets -- -D warnings  # lints
cargo test                                 # all tests
cargo llvm-cov --workspace --all-targets   # coverage
cargo bench                                # benchmarks

Install pre-commit hooks:

pre-commit install
pre-commit install --hook-type pre-push

Status

The repository is stable and actively maintained. cmakefmt is still pre-1.0, so release packaging, package-manager distribution, and some output or API details may continue to evolve. The built-in command registry is audited through CMake 4.3.1.

Hit something unexpected? See Troubleshooting or run:

cmakefmt --debug --check path/to/CMakeLists.txt

License

cmakefmt is dual-licensed under MIT or Apache-2.0 at your option.