Add toolchains support to Gradle plugin

detekt-cli/src/main/kotlin/io/gitlab/arturbosch/detekt/cli/CliArgs.kt

@@ -193,6 +193,13 @@ class CliArgs {
     )
     var jvmTarget: String = JvmTarget.DEFAULT.description
 
+    @Parameter(
+        names = ["--jdk-home"],
+        description = "EXPERIMENTAL: Use a custom JDK home directory to include into the classpath",
+        converter = PathConverter::class
+    )
+    var jdkHome: Path? = null
+
     @Parameter(
         names = ["--version"],
         description = "Prints the detekt CLI version."

detekt-cli/src/main/kotlin/io/gitlab/arturbosch/detekt/cli/Spec.kt

@@ -68,6 +68,7 @@ internal fun CliArgs.createSpec(output: Appendable, error: Appendable): Processi
             jvmTarget = args.jvmTarget
             languageVersion = args.languageVersion?.versionString
             classpath = args.classpath?.trim()
+            jdkHome = args.jdkHome
         }
     }
 }

detekt-core/src/main/kotlin/io/gitlab/arturbosch/detekt/core/settings/EnvironmentAware.kt

@@ -33,7 +33,8 @@ internal class EnvironmentFacade(
             projectSpec.inputPaths.toList(),
             classpath,
             compilerSpec.parseLanguageVersion(),
-            compilerSpec.parseJvmTarget()
+            compilerSpec.parseJvmTarget(),
+            compilerSpec.jdkHome,
         )
         createKotlinCoreEnvironment(compilerConfiguration, disposable)
     }

detekt-gradle-plugin/settings.gradle.kts

@@ -2,6 +2,8 @@ pluginManagement {
     includeBuild("../build-logic")
 }
 
+includeBuild("..")
+
 dependencyResolutionManagement {
     versionCatalogs {
         create("libs") {

detekt-gradle-plugin/src/main/kotlin/io/gitlab/arturbosch/detekt/Detekt.kt

@@ -19,13 +19,15 @@ import io.gitlab.arturbosch.detekt.invoke.DetektInvoker
 import io.gitlab.arturbosch.detekt.invoke.DisableDefaultRuleSetArgument
 import io.gitlab.arturbosch.detekt.invoke.FailFastArgument
 import io.gitlab.arturbosch.detekt.invoke.InputArgument
+import io.gitlab.arturbosch.detekt.invoke.JdkHomeArgument
 import io.gitlab.arturbosch.detekt.invoke.JvmTargetArgument
 import io.gitlab.arturbosch.detekt.invoke.LanguageVersionArgument
 import io.gitlab.arturbosch.detekt.invoke.ParallelArgument
 import io.gitlab.arturbosch.detekt.invoke.isDryRunEnabled
 import org.gradle.api.Action
 import org.gradle.api.file.ConfigurableFileCollection
 import org.gradle.api.file.Directory
+import org.gradle.api.file.DirectoryProperty
 import org.gradle.api.file.FileTree
 import org.gradle.api.file.RegularFile
 import org.gradle.api.file.RegularFileProperty
@@ -38,6 +40,7 @@ import org.gradle.api.tasks.Classpath
 import org.gradle.api.tasks.Console
 import org.gradle.api.tasks.IgnoreEmptyDirectories
 import org.gradle.api.tasks.Input
+import org.gradle.api.tasks.InputDirectory
 import org.gradle.api.tasks.InputFile
 import org.gradle.api.tasks.InputFiles
 import org.gradle.api.tasks.Internal
@@ -96,6 +99,11 @@ abstract class Detekt @Inject constructor(
         get() = jvmTargetProp.get()
         set(value) = jvmTargetProp.set(value)
 
+    @get:InputDirectory
+    @get:PathSensitive(PathSensitivity.ABSOLUTE)
+    @get:Optional
+    abstract val jdkHome: DirectoryProperty
+
     @get:Internal
     internal abstract val debugProp: Property<Boolean>
     var debug: Boolean
@@ -216,6 +224,7 @@ abstract class Detekt @Inject constructor(
             ClasspathArgument(classpath),
             LanguageVersionArgument(languageVersionProp.orNull),
             JvmTargetArgument(jvmTargetProp.orNull),
+            JdkHomeArgument(jdkHome),
             ConfigArgument(config),
             BaselineArgument(baseline.orNull),
             DefaultReportArgument(DetektReportType.XML, xmlReportFile.orNull),

detekt-gradle-plugin/src/main/kotlin/io/gitlab/arturbosch/detekt/DetektCreateBaselineTask.kt

@@ -17,6 +17,7 @@ import io.gitlab.arturbosch.detekt.invoke.InputArgument
 import io.gitlab.arturbosch.detekt.invoke.JvmTargetArgument
 import io.gitlab.arturbosch.detekt.invoke.ParallelArgument
 import org.gradle.api.file.ConfigurableFileCollection
+import org.gradle.api.file.DirectoryProperty
 import org.gradle.api.file.FileTree
 import org.gradle.api.file.RegularFileProperty
 import org.gradle.api.provider.Property
@@ -26,6 +27,7 @@ import org.gradle.api.tasks.Classpath
 import org.gradle.api.tasks.Console
 import org.gradle.api.tasks.IgnoreEmptyDirectories
 import org.gradle.api.tasks.Input
+import org.gradle.api.tasks.InputDirectory
 import org.gradle.api.tasks.InputFiles
 import org.gradle.api.tasks.Internal
 import org.gradle.api.tasks.Optional
@@ -113,6 +115,11 @@ abstract class DetektCreateBaselineTask : SourceTask() {
         get() = jvmTargetProp.get()
         set(value) = jvmTargetProp.set(value)
 
+    @get:InputDirectory
+    @get:PathSensitive(PathSensitivity.ABSOLUTE)
+    @get:Optional
+    abstract val jdkHome: DirectoryProperty
+
     @get:Internal
     internal val arguments: Provider<List<String>> = project.provider {
         listOf(

detekt-gradle-plugin/src/main/kotlin/io/gitlab/arturbosch/detekt/internal/SharedTasks.kt

@@ -3,8 +3,12 @@ package io.gitlab.arturbosch.detekt.internal
 import io.gitlab.arturbosch.detekt.Detekt
 import io.gitlab.arturbosch.detekt.DetektCreateBaselineTask
 import io.gitlab.arturbosch.detekt.extensions.DetektExtension
+import org.gradle.api.JavaVersion
 import org.gradle.api.Project
+import org.gradle.api.plugins.JavaBasePlugin
+import org.gradle.api.plugins.JavaPluginExtension
 import org.gradle.api.tasks.TaskProvider
+import org.gradle.jvm.toolchain.JavaToolchainService
 
 internal fun Project.registerDetektTask(
     name: String,
@@ -40,6 +44,20 @@ internal fun Project.registerDetektTask(
             }
         }
 
+        project.plugins.withType(JavaBasePlugin::class.java) { _ ->
+            val toolchain = project.extensions.getByType(JavaPluginExtension::class.java).toolchain
+
+            // acquire a provider that returns the launcher for the toolchain
+            val service = project.extensions.getByType(JavaToolchainService::class.java)
+            val defaultLauncher = service.launcherFor(toolchain)
+            it.jdkHome.convention(defaultLauncher.map { launcher -> launcher.metadata.installationPath })
+            it.jvmTargetProp.convention(
+                defaultLauncher.map { launcher ->
+                    JavaVersion.toVersion(launcher.metadata.languageVersion.asInt()).toString()
+                }
+            )
+        }
+
         it.debugProp.convention(provider { extension.debug })
         it.parallelProp.convention(provider { extension.parallel })
         it.disableDefaultRuleSetsProp.convention(provider { extension.disableDefaultRuleSets })
@@ -59,6 +77,20 @@ internal fun Project.registerCreateBaselineTask(
     configuration: DetektCreateBaselineTask.() -> Unit
 ): TaskProvider<DetektCreateBaselineTask> =
     tasks.register(name, DetektCreateBaselineTask::class.java) {
+        project.plugins.withType(JavaBasePlugin::class.java) { _ ->
+            val toolchain = project.extensions.getByType(JavaPluginExtension::class.java).toolchain
+
+            // acquire a provider that returns the launcher for the toolchain
+            val service = project.extensions.getByType(JavaToolchainService::class.java)
+            val defaultLauncher = service.launcherFor(toolchain)
+            it.jdkHome.convention(defaultLauncher.map { launcher -> launcher.metadata.installationPath })
+            it.jvmTargetProp.convention(
+                defaultLauncher.map { launcher ->
+                    JavaVersion.toVersion(launcher.metadata.languageVersion.asInt()).toString()
+                }
+            )
+        }
+
         it.config.setFrom(project.provider { extension.config })
         it.debug.convention(project.provider { extension.debug })
         it.parallel.convention(project.provider { extension.parallel })

detekt-gradle-plugin/src/main/kotlin/io/gitlab/arturbosch/detekt/invoke/CliArgument.kt

@@ -1,6 +1,7 @@
 package io.gitlab.arturbosch.detekt.invoke
 
 import io.gitlab.arturbosch.detekt.extensions.DetektReportType
+import org.gradle.api.file.DirectoryProperty
 import org.gradle.api.file.FileCollection
 import org.gradle.api.file.RegularFile
 import java.io.File
@@ -21,6 +22,7 @@ private const val CREATE_BASELINE_PARAMETER = "--create-baseline"
 private const val CLASSPATH_PARAMETER = "--classpath"
 private const val LANGUAGE_VERSION_PARAMETER = "--language-version"
 private const val JVM_TARGET_PARAMETER = "--jvm-target"
+private const val JDK_HOME_PARAMETER = "--jdk-home"
 private const val BASE_PATH_PARAMETER = "--base-path"
 
 internal sealed class CliArgument {
@@ -58,6 +60,10 @@ internal data class JvmTargetArgument(val jvmTarget: String?) : CliArgument() {
     override fun toArgument() = jvmTarget?.let { listOf(JVM_TARGET_PARAMETER, it) }.orEmpty()
 }
 
+internal data class JdkHomeArgument(val jdkHome: DirectoryProperty) : CliArgument() {
+    override fun toArgument() = jdkHome.orNull?.let { listOf(JDK_HOME_PARAMETER, it.toString()) }.orEmpty()
+}
+
 internal data class BaselineArgument(val baseline: RegularFile?) : CliArgument() {
     override fun toArgument() = baseline?.let { listOf(BASELINE_PARAMETER, it.asFile.absolutePath) }.orEmpty()
 }

detekt-gradle-plugin/src/test/kotlin/io/gitlab/arturbosch/detekt/cli/Main.kt

@@ -1,5 +1,5 @@
 @file:JvmName("Main")
-@file:Suppress("unused", "UNUSED_PARAMETER")
+@file:Suppress("unused", "UNUSED_PARAMETER", "Filename")
 
 package io.gitlab.arturbosch.detekt.cli
 

detekt-parser/src/main/kotlin/io/github/detekt/parser/KotlinEnvironmentUtils.kt

@@ -67,7 +67,8 @@ fun createCompilerConfiguration(
     pathsToAnalyze: List<Path>,
     classpath: List<String>,
     languageVersion: LanguageVersion?,
-    jvmTarget: JvmTarget
+    jvmTarget: JvmTarget,
+    jdkHome: Path?,
 ): CompilerConfiguration {
     val javaFiles = pathsToAnalyze.flatMap { path ->
         path.toFile().walk()
@@ -99,6 +100,8 @@ fun createCompilerConfiguration(
         addJavaSourceRoots(javaFiles)
         addKotlinSourceRoots(kotlinFiles)
         addJvmClasspathRoots(classpathFiles)
+
+        jdkHome?.let { put(JVMConfigurationKeys.JDK_HOME, it.toFile()) }
         configureJdkClasspathRoots()
     }
 }

detekt-tooling/api/detekt-tooling.api

@@ -116,6 +116,7 @@ public abstract interface class io/github/detekt/tooling/api/spec/BaselineSpec {
 
 public abstract interface class io/github/detekt/tooling/api/spec/CompilerSpec {
 	public abstract fun getClasspath ()Ljava/lang/String;
+	public abstract fun getJdkHome ()Ljava/nio/file/Path;
 	public abstract fun getJvmTarget ()Ljava/lang/String;
 	public abstract fun getLanguageVersion ()Ljava/lang/String;
 }
@@ -243,9 +244,11 @@ public final class io/github/detekt/tooling/dsl/CompilerSpecBuilder : io/github/
 	public fun build ()Lio/github/detekt/tooling/api/spec/CompilerSpec;
 	public synthetic fun build ()Ljava/lang/Object;
 	public final fun getClasspath ()Ljava/lang/String;
+	public final fun getJdkHome ()Ljava/nio/file/Path;
 	public final fun getJvmTarget ()Ljava/lang/String;
 	public final fun getLanguageVersion ()Ljava/lang/String;
 	public final fun setClasspath (Ljava/lang/String;)V
+	public final fun setJdkHome (Ljava/nio/file/Path;)V
 	public final fun setJvmTarget (Ljava/lang/String;)V
 	public final fun setLanguageVersion (Ljava/lang/String;)V
 }

detekt-tooling/src/main/kotlin/io/github/detekt/tooling/api/spec/CompilerSpec.kt

@@ -1,5 +1,7 @@
 package io.github.detekt.tooling.api.spec
 
+import java.nio.file.Path
+
 /**
  * All these properties are based down to the Kotlin compiler for type- and symbol resolution.
  */
@@ -19,4 +21,10 @@ interface CompilerSpec {
      * Paths to class files and jars separated by a path separator.
      */
     val classpath: String?
+
+    /**
+     * Path to custom JDK home. Includes the custom JDK from the specified location into the classpath instead of using
+     * the JRE from the runtime environment.
+     */
+    val jdkHome: Path?
 }

detekt-tooling/src/main/kotlin/io/github/detekt/tooling/dsl/CompilerSpecBuilder.kt

@@ -1,19 +1,22 @@
 package io.github.detekt.tooling.dsl
 
 import io.github.detekt.tooling.api.spec.CompilerSpec
+import java.nio.file.Path
 
 @ProcessingModelDsl
 class CompilerSpecBuilder : Builder<CompilerSpec> {
 
     var jvmTarget: String = "1.8"
     var languageVersion: String? = null
     var classpath: String? = null
+    var jdkHome: Path? = null
 
-    override fun build(): CompilerSpec = CompilerModel(jvmTarget, languageVersion, classpath)
+    override fun build(): CompilerSpec = CompilerModel(jvmTarget, languageVersion, classpath, jdkHome)
 }
 
 private data class CompilerModel(
     override val jvmTarget: String,
     override val languageVersion: String?,
-    override val classpath: String?
+    override val classpath: String?,
+    override val jdkHome: Path?,
 ) : CompilerSpec