cmakefmt

opinionated cmake formatting

Documentation | Getting Started | Configuration

cmakefmt takes your CMake source files (CMakeLists.txt and *.cmake), applies a consistent set of formatting rules, and outputs the result. It normalizes command casing, keyword casing, indentation, argument wrapping, alignment, and more -- with nearly 40 configuration options. If a file cannot be parsed, the formatter returns it unchanged -- it never silently corrupts your code.

Before / After

Features

• Command casing -- normalizes PROJECT, Set, IF to lowercase (or uppercase)
• Keyword & literal casing -- normalizes public, Private to PUBLIC, PRIVATE; on/Off to ON/OFF
• Argument wrapping -- multiple strategies (cascade, vertical) with firstArgSameLine, wrapArgThreshold, and per-command overrides
• Alignment -- aligns property values, condition arguments, and keyword groups
• Comment formatting -- reflowing, indentation, and trailing comment alignment
• Sorting -- alphabetical sorting of argument lists under configurable keywords
• Blank line control -- maxBlankLines, minBlankLinesBetweenBlocks, blankLineBetweenSections for structural spacing
• Generator expressions -- $<...> expressions are recognized and treated atomically, never broken across lines
• Line endings & final newline -- LF/CRLF/auto normalization, trailing whitespace removal
• Per-command overrides -- fine-grained control over individual commands (e.g. spaceBeforeParen for if)
• Inline pragmas -- # cmakefmt: off/on/skip to suppress formatting, push { ... }/pop for scoped config overrides
• Config inheritance -- extends key for sharing base configs across projects
• Safe by default -- unparseable input is returned unchanged; never silently corrupts

Installation

cargo install

cargo install cmakefmt-cli

Prebuilt Binaries

Download prebuilt binaries for your platform from GitHub Releases:

• linux-x64, linux-arm64
• macos-x64, macos-arm64
• windows-x64, windows-arm64

dprint Plugin

Add cmakefmt as a WASM plugin in your dprint.json:

{
  "plugins": [
    "https://github.com/azais-corentin/cmakefmt/releases/latest/download/cmakefmt-dprint.wasm"
  ]
}

Quick Start

Format a file and print to stdout:

cmakefmt CMakeLists.txt

Format in place:

cmakefmt --write CMakeLists.txt  # also: --inplace

Check formatting without modifying files (exits with code 1 if changes are needed):

cmakefmt --check CMakeLists.txt

Show a unified diff of what would change:

cmakefmt --diff CMakeLists.txt

Format from stdin:

cat CMakeLists.txt | cmakefmt --stdin

Configuration

Create a .cmakefmt.toml (or cmakefmt.toml) in your project root. The formatter discovers config by walking from the formatted file's directory upward to the filesystem root. All keys use camelCase (snake_case is also accepted).

lineWidth = 120
indentWidth = 4
indentStyle = "space"
commandCase = "lower"
keywordCase = "upper"
closingParenNewline = true
lineEnding = "lf"
finalNewline = true
trimTrailingWhitespace = true
endCommandArgs = "remove"

sortArguments = ["SOURCES", "FILES"]
alignPropertyValues = true

ignorePatterns = ["build/**", "third_party/**"]
ignoreCommands = ["ExternalProject_Add"]

[perCommandConfig.if]
spaceBeforeParen = true

[perCommandConfig.elseif]
spaceBeforeParen = true

For the full list of options and their defaults, see the Configuration Reference.

Editor Integration

External Formatter (stdin pipe)

Most editors can invoke an external command to format the current buffer. Configure your editor to pipe through:

cmakefmt --stdin --assume-filename <path>

The --assume-filename flag tells cmakefmt which file path to use for config discovery (walking upward to find .cmakefmt.toml).

dprint

If you use dprint, add the cmakefmt WASM plugin to your dprint.json (see the Installation section above), then use dprint's editor extensions for VS Code, Neovim, or other supported editors.

Documentation

Full documentation is available at azais-corentin.github.io/cmakefmt.

License

MIT -- see LICENSE for details.