Painless Gradle plugin for linting and formatting Kotlin source files using the awesome ktlint engine.
It aims to be easy to set up with zero required configuration and behaves as you'd expect out of the box.
It's also fast because it integrates the ktlint engine directly with Gradle's incremental build and uses the Worker API to parallelize work.
Available on the Gradle Plugins Portal: https://plugins.gradle.org/plugin/org.jmailen.kotlinter
Kotlin
plugins {
id("org.jmailen.kotlinter") version "4.4.1"
}Groovy
plugins {
id "org.jmailen.kotlinter" version "4.4.1"
}Kotlin
Root `build.gradle.kts`plugins {
id("org.jmailen.kotlinter") version "4.4.1" apply false
}Each module build.gradle.kts with Kotlin source
plugins {
id("org.jmailen.kotlinter")
}Groovy
Root `build.gradle`plugins {
id 'org.jmailen.kotlinter' version "4.4.1" apply false
}Each module build.gradle with Kotlin source
plugins {
id 'org.jmailen.kotlinter'
}| kotlinter version | min kotlin version | max kotlin version | min gradle version |
|---|---|---|---|
| 4.2.0+ | 1.9.20 | - | 8.4 |
| 4.0.0+ | 1.9.0 | - | 7.6 |
| 3.14.0+ | 1.8.0 | 1.8.22 | 7.6 |
| 3.11.0+ | 1.7.0 | 1.7.22 | 7.0 |
| 3.10.0+ | 1.6.20 | 1.6.21 | 7.0 |
| 3.7.0+ | 1.5.31 | 1.6.10 | 7.0 |
| 3.5.0+ | 1.5.0 | 1.5.30 | 6.8 |
| 3.0.0+ | 1.4.0 | 1.4.30 | 6.8 |
| 2.0.0+ | 1.3.0 | 1.3.30 | - |
- Supports Kotlin Gradle plugins:
- Supports
.ktand.ktsfiles - Standalone
LintTaskandFormatTasktypes for defining custom tasks - Incremental build support and fast parallelization with Gradle Worker API
- Configures from
.editorconfigwhen available - Configurable reporters
When your project uses one of the supported Kotlin Gradle plugins, Kotlinter adds these tasks:
formatKotlin: format Kotlin source code according to ktlint rules or warn when auto-format not possible.
lintKotlin: report Kotlin lint errors and by default fail the build.
Also check becomes dependent on lintKotlin.
Granular tasks are added for each source set in the project: formatKotlinSourceSet and lintKotlinSourceSet.
Kotlinter can install a hook to run pre-push (installKotlinterPrePushHook). The hook runs lintKotlin and, if there are errors, formatKotlin and exits non-zero leaving changed files to be committed.
You must apply the kotlinter plugin to your root project to make this task available. If using git worktree you must install the hook from the parent git directory.
To install the hook automatically when someone runs the build, add this to your root project build.gradle.kts:
Kotlin
tasks.check {
dependsOn("installKotlinterPrePushHook")
}Groovy
tasks.named('check') {
dependsOn 'installKotlinterPrePushHook'
}Options are configured in the kotlinter extension. Defaults shown (you may omit the configuration block entirely if you want these defaults).
Kotlin
kotlinter {
failBuildWhenCannotAutoFormat = false
ignoreFailures = false
reporters = arrayOf("checkstyle", "plain")
}Groovy
kotlinter {
failBuildWhenCannotAutoFormat = false
ignoreFailures = false
reporters = ['checkstyle', 'plain']
}Setting failBuildWhenCannotAutoFormat to true will configure the formatKotlin task to fail the build when auto-format is not able to fix a lint error. This is overrided by setting ignoreFailures to true.
Options for reporters: checkstyle, html, json, plain, sarif
Reporters behave as described at: https://github.com/pinterest/ktlint
Kotlinter will configure itself using an .editorconfig file if one is present.
This configuration includes code style and linting rules.
See KtLint configuration for details.
The formatKotlinSourceSet and lintKotlinSourceSet tasks inherit from SourceTask
so you can customize includes, excludes, and source.
Kotlin
tasks.withType<LintTask> {
this.source = this.source.minus(fileTree("src/generated")).asFileTree
}
tasks.withType<FormatTask> {
this.source = this.source.minus(fileTree("src/generated")).asFileTree
}Groovy
tasks.named("lintKotlinMain") {
source = source - fileTree("$buildDir/generated")
}Note that exclude paths are relative to the package root.
If you aren't using autoconfiguration from a supported plugin or otherwise need to handle additional source code, you can create custom tasks:
Kotlin
import org.jmailen.gradle.kotlinter.tasks.LintTask
import org.jmailen.gradle.kotlinter.tasks.FormatTask
tasks.register<LintTask>("ktLint") {
group = "verification"
source(files("src"))
reports.set(
mapOf(
"plain" to file("build/lint-report.txt"),
"json" to file("build/lint-report.json")
)
)
}
tasks.register<FormatTask>("ktFormat") {
group = "formatting"
source(files("src"))
report.set(file("build/format-report.txt"))
}Groovy
import org.jmailen.gradle.kotlinter.tasks.LintTask
import org.jmailen.gradle.kotlinter.tasks.FormatTask
tasks.register('ktLint', LintTask) {
group 'verification'
source files('src')
reports = [
'plain': file('build/lint-report.txt'),
'json' : file('build/lint-report.json')
]
}
tasks.register('ktFormat', FormatTask) {
group 'formatting'
source files('src/test')
report = file('build/format-report.txt')
}If you need to use a different version of ktlint you can override the dependency.
Kotlin or Groovy
buildscript {
configurations.classpath {
resolutionStrategy {
force(
"com.pinterest.ktlint:ktlint-rule-engine:1.2.1",
"com.pinterest.ktlint:ktlint-rule-engine-core:1.2.1",
"com.pinterest.ktlint:ktlint-cli-reporter-core:1.2.1",
"com.pinterest.ktlint:ktlint-cli-reporter-checkstyle:1.2.1",
"com.pinterest.ktlint:ktlint-cli-reporter-json:1.2.1",
"com.pinterest.ktlint:ktlint-cli-reporter-html:1.2.1",
"com.pinterest.ktlint:ktlint-cli-reporter-plain:1.2.1",
"com.pinterest.ktlint:ktlint-cli-reporter-sarif:1.2.1",
"com.pinterest.ktlint:ktlint-ruleset-standard:1.2.1"
)
}
}
}
Alternatively, if you have a custom build convention plugin that utilizes kotlinter, you can enforce a newer KtLint version through a platform directive:
Kotlin or Groovy
dependencies {
implementation(platform("com.pinterest.ktlint:ktlint-bom:1.2.1"))
implementation("org.jmailen.gradle:kotlinter-gradle:4.4.1")
}
You can add custom ktlint RuleSets using the buildscript classpath:
Kotlin
buildscript {
dependencies {
classpath(files("libs/my-custom-ktlint-rules.jar"))
classpath("org.other.ktlint:custom-rules:1.0")
}
}Groovy
buildscript {
dependencies {
classpath files('libs/my-custom-ktlint-rules.jar')
classpath 'org.other.ktlint:custom-rules:1.0'
}
}
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