remove support for ktlint < 1

increase minimum kotlin version to 1.7 because less than this is deprecated by KGP and support will be removed soon
update default ktlint version to 1.5 in order to avoid unnecessary bug reports such as #815 and #809

Author: wakingrufus

.editorconfig

@@ -11,6 +11,9 @@ ij_kotlin_packages_to_use_import_on_demand = unset
 ij_kotlin_name_count_to_use_star_import = 999
 ij_kotlin_name_count_to_use_star_import_for_members = 999
 ktlint_code_style=intellij_idea
+ktlint_standard_function-expression-body = disabled
+ktlint_standard_function-signature = disabled
+ktlint_standard_class-signature = disabled
 
 [*.{yml,yaml}]
 indent_size = 2

CHANGELOG.md

@@ -7,6 +7,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/).
 
 ## [Unreleased]
 
+- remove support for ktlint < 1 [#889](https://github.com/JLLeitschuh/ktlint-gradle/pull/889)
+- increase minimum kotlin version to 1.7 [#889](https://github.com/JLLeitschuh/ktlint-gradle/pull/889)
+- update default ktlint version to 1.5 [#889](https://github.com/JLLeitschuh/ktlint-gradle/pull/889)
+
 ## [12.3.0] - 2025-05-22
 
 ### Changed

plugin/.editorconfig

@@ -13,6 +13,9 @@ ij_kotlin_name_count_to_use_star_import_for_members = 999
 ij_kotlin_allow_trailing_comma = false
 ij_kotlin_allow_trailing_comma_on_call_site = false
 ktlint_code_style=intellij_idea
+ktlint_standard_function-expression-body = disabled
+ktlint_standard_function-signature = disabled
+ktlint_standard_class-signature = disabled
 
 [*.{yml,yaml}]
 indent_size = 2

plugin/build.gradle.kts

@@ -4,6 +4,8 @@ import com.github.jengelman.gradle.plugins.shadow.tasks.ShadowJar
 import com.gradle.enterprise.gradleplugin.testretry.retry
 import org.gradle.api.tasks.testing.logging.TestExceptionFormat
 import org.gradle.api.tasks.testing.logging.TestLogEvent
+import org.jetbrains.kotlin.gradle.dsl.JvmTarget
+import org.jetbrains.kotlin.gradle.dsl.KotlinVersion
 import org.jetbrains.kotlin.gradle.tasks.KotlinCompile
 import org.jetbrains.kotlin.util.prefixIfNot
 
@@ -32,15 +34,14 @@ java {
 }
 
 ktlint {
-    version.set("1.1.0")
+    version.set("1.6.0")
 }
 
 tasks.withType<KotlinCompile> {
-    kotlinOptions {
-        // target 1.4 as ktlint 0.49 requires it for inline classes
-        languageVersion = "1.4"
-        apiVersion = "1.4"
-        jvmTarget = "1.8"
+    compilerOptions {
+        languageVersion.set(KotlinVersion.KOTLIN_1_7)
+        apiVersion.set(KotlinVersion.KOTLIN_1_7)
+        jvmTarget.set(JvmTarget.JVM_1_8)
     }
 }
 
@@ -65,27 +66,12 @@ configurations["testImplementation"].extendsFrom(shadowImplementation)
 sourceSets {
     val adapter by creating {
     }
-    val adapter47 by creating {
-        compileClasspath += adapter.output
-    }
-    val adapter48 by creating {
-        compileClasspath += adapter.output
-    }
-    val adapter49 by creating {
-        compileClasspath += adapter.output
-    }
-    val adapter50 by creating {
-        compileClasspath += adapter.output
-    }
+
     val adapter100 by creating {
         compileClasspath += adapter.output
     }
     val adapters = listOf(
         adapter,
-        adapter47,
-        adapter48,
-        adapter49,
-        adapter50,
         adapter100
     )
     val main by getting {
@@ -105,10 +91,6 @@ sourceSets {
 
 val adapterSources = listOf(
     sourceSets.named("adapter"),
-    sourceSets.named("adapter47"),
-    sourceSets.named("adapter48"),
-    sourceSets.named("adapter49"),
-    sourceSets.named("adapter50"),
     sourceSets.named("adapter100")
 )
 
@@ -125,24 +107,9 @@ tasks.named<Jar>("shadowJar").configure {
 }
 
 dependencies {
-    add("adapterCompileOnly", "com.pinterest.ktlint:ktlint-core:0.34.0")
     add("adapterImplementation", libs.commons.io)
     add("adapterImplementation", libs.semver)
 
-    add("adapter47CompileOnly", "com.pinterest.ktlint:ktlint-core:0.47.1")
-    add("adapter48CompileOnly", "com.pinterest.ktlint:ktlint-core:0.48.2")
-
-    add("adapter49CompileOnly", "com.pinterest.ktlint:ktlint-core:0.49.1")
-    add("adapter49CompileOnly", "com.pinterest.ktlint:ktlint-cli-reporter:0.49.1")
-    add("adapter49CompileOnly", "com.pinterest.ktlint:ktlint-rule-engine:0.49.1")
-    add("adapter49CompileOnly", "com.pinterest.ktlint:ktlint-ruleset-standard:0.49.1")
-    add("adapter49CompileOnly", "com.pinterest.ktlint:ktlint-reporter-baseline:0.49.1")
-
-    add("adapter50CompileOnly", "com.pinterest.ktlint:ktlint-cli-reporter:0.50.0")
-    add("adapter50CompileOnly", "com.pinterest.ktlint:ktlint-rule-engine:0.50.0")
-    add("adapter50CompileOnly", "com.pinterest.ktlint:ktlint-ruleset-standard:0.50.0")
-    add("adapter50CompileOnly", "com.pinterest.ktlint:ktlint-reporter-baseline:0.50.0")
-
     add("adapter100CompileOnly", "com.pinterest.ktlint:ktlint-cli-reporter-core:1.0.0")
     add("adapter100CompileOnly", "com.pinterest.ktlint:ktlint-rule-engine:1.0.0")
     add("adapter100CompileOnly", "com.pinterest.ktlint:ktlint-ruleset-standard:1.0.0")
@@ -160,7 +127,7 @@ dependencies {
     testImplementation(libs.junit.jupiter)
     testImplementation(libs.assertj.core)
     testImplementation(libs.kotlin.reflect)
-    testImplementation(libs.ktlint.core)
+    testImplementation(libs.ktlint.rule.engine)
     testImplementation(libs.archunit.junit5)
 }
 
@@ -179,10 +146,8 @@ kotlin {
 tasks.withType<Test> {
     dependsOn("publishToMavenLocal")
     useJUnitPlatform()
-    maxParallelForks = (Runtime.getRuntime().availableProcessors() / 2).takeIf { it > 0 } ?: 1
-    doFirst {
-        logger.lifecycle("maxParallelForks for '$path' is $maxParallelForks")
-    }
+    maxParallelForks = 6 // no point in this being higher than the number of gradle workers
+
     // Set the system property for the project version to be used in the tests
     systemProperty("project.version", project.version.toString())
     testLogging {

plugin/gradle.properties

@@ -4,6 +4,6 @@ org.gradle.vfs.watch=true
 # Shadow plugin does not fully support configuration cache: https://github.com/johnrengelman/shadow/issues/687
 #org.gradle.unsafe.configuration-cache=true
 
-org.gradle.workers.max = 4
+org.gradle.workers.max = 6
 # Used by the nebula release plugin to locate the root git directory
 git.root=..

plugin/gradle/libs.versions.toml

@@ -1,6 +1,6 @@
 [versions]
 kotlin = "1.5.31"
-ktlint = "0.47.1" # last version prior to API changes. we can increase this more once we drop support for the old API.
+ktlint = "1.0.0"
 androidPlugin = "4.1.0"
 semver = "1.1.1"
 jgit = "5.13.3.202401111512-r"
@@ -22,6 +22,6 @@ junit-jupiter = { module = "org.junit.jupiter:junit-jupiter", version.ref = "jun
 kotlin-gradle-plugin = { module = "org.jetbrains.kotlin:kotlin-gradle-plugin", version.ref = "kotlin" }
 kotlin-reflect = { module = "org.jetbrains.kotlin:kotlin-reflect", version.ref = "kotlin" }
 kotlin-script-runtime = { module = "org.jetbrains.kotlin:kotlin-script-runtime", version.ref = "kotlin" }
-ktlint-core = { module = "com.pinterest.ktlint:ktlint-core", version.ref = "ktlint" }
+ktlint-rule-engine = { module = "com.pinterest.ktlint:ktlint-rule-engine", version.ref = "ktlint" }
 semver = { module = "net.swiftzer.semver:semver", version.ref = "semver" }
 slf4j-nop = { module = "org.slf4j:slf4j-nop", version.ref = "sl4fj" }

plugin/src/adapter/kotlin/org/jlleitschuh/gradle/ktlint/worker/BaselineReporterAdapter.kt

@@ -16,11 +16,3 @@ data class SerializableLintError(
         private const val serialVersionUID: Long = 20120922L
     }
 }
-
-fun List<SerializableLintError>.containsLintError(error: SerializableLintError): Boolean {
-    return firstOrNull { lintError ->
-        lintError.col == error.col &&
-            lintError.line == error.line &&
-            lintError.ruleId == error.ruleId
-    } != null
-}