Kotlin Formatter

This project provides:

• A command-line tool for formatting Kotlin source code files, implemented as a wrapper around ktfmt.
• An IntelliJ idea plugin for formatting Kotlin source code files.

It can be used to automate code formatting, ensuring a clean and consistent codebase, while integrating seamlessly into development workflows.

The CLI tool can:

• Format files and directories: Apply consistent formatting to files, directories, or standard input.
• Integrate with Git workflows:
  • Pre-commit: Format staged files before committing.
  • Pre-push: Check committed files before pushing.

The plugin can format Kotlin files on save, or on the format action.

CLI Usage

kotlin-format [OPTIONS] [FILES...]

Options

Option	Description
--set-exit-if-changed	Exit with a non-zero code if any files needed changes.
--dry-run	Display the changes that would be made without writing them to disk.
--pre-commit	Format staged files as part of the pre-commit process. Mutually exclusive with --pre-push.
--pre-push	Check committed files as part of the pre-push process. Mutually exclusive with --pre-commit.
--push-commit=<text>	The SHA of the commit to use for pre-push. Defaults to HEAD.
--print-stats	Emit performance-related statistics to help diagnose performance issues.
-h, --help	Show help message and exit.

Arguments

Argument	Description
<files>	Files or directories to format. Use - for standard input.

Installing CLI

There are multiple ways to install and use the Kotlin Formatter CLI:

1. Using Hermit

If you don't have Hermit installed, follow the Hermit Getting Started Guide to install it first. Once Hermit is installed, you can install the Kotlin Formatter CLI using:

hermit install kotlin-format

Once installed, you can run the CLI with:

kotlin-format [OPTIONS] [FILES...]

2. Downloading the pre-packaged distribution with a script

A pre-packaged distribution is available on Maven Central and GitHub Releases

VERSION=X.Y.Z
curl -L -o kotlin-formatter-dist.zip https://github.com/block/kotlin-formatter/releases/download/$VERSION/kotlin-formatter-dist-$VERSION.zip
unzip kotlin-formatter-dist.zip
cd kotlin-format-shadow-$VERSION

Once downloaded and extracted, you can run the CLI with:

./bin/kotlin-format [OPTIONS] [FILES...]

3. Downloading the JAR manually

A fat JAR of the CLI is available on Maven Central and GitHub Releases. Once downloaded, you can run the CLI with:

java -jar path/to/kotlin-formatter-$version-all.jar [OPTIONS] [FILES...]

IntelliJ IDEA Plugin Usage

A properties file can be used to configure the plugin for each project. The properties file should be named kotlin-formatter.properties and placed in the .idea of the project. The following properties are supported:

• kotlin-formatter.enabled: Enable or disable the plugin, disabled by default.
• kotlin-formatter.script-path: Path to the Kotlin Formatter script. The kotlin-format library in this project is used if this is not specified.

Example:

kotlin-formatter.enabled=true
kotlin-formatter.script-path=bin/kotlin-format

Changes to these config require an IDE restart to take effect.

To enable formatting of files on save, navigate to "Settings" > "Tools" > Actions on Save", activate the "Reformat code" checkbox, and ensure that the "Kotlin" file type is selected. Make sure "Optimize imports" is NOT enabled for the "Kotlin" file type.

IntelliJ IDEA Plugin Installation

Download from JetBrains Marketplace