Fix test runtime Java versions

.github/workflows/gradle-test.pr.yml

@@ -10,32 +10,36 @@ jobs:
   test-ubuntu:
     strategy:
       matrix:
-        version: [ 8, 11, 17 ]
+        javaVersion: [ 8, 11, 17 ]
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v3
       - uses: actions/setup-java@v3
         with:
           distribution: 'zulu'
-          java-version: ${{ matrix.version }}
+          java-version: ${{ matrix.javaVersion }}
           cache: 'maven'
       - uses: gradle/gradle-build-action@v2
+        env:
+          ORG_GRADLE_PROJECT_org.jetbrains.dokka.javaToolchain.test: ${{ matrix.javaVersion }}
         with:
           arguments: clean test --stacktrace
 
   test-windows:
     strategy:
       matrix:
-        version: [ 11, 17 ]
+        javaVersion: [ 11, 17 ]
       fail-fast: false
     runs-on: windows-latest
     steps:
       - uses: actions/checkout@v3
       - uses: actions/setup-java@v3
         with:
           distribution: 'zulu'
-          java-version: ${{ matrix.version }}
+          java-version: ${{ matrix.javaVersion }}
           cache: 'maven'
       - uses: gradle/gradle-build-action@v2
+        env:
+          ORG_GRADLE_PROJECT_org.jetbrains.dokka.javaToolchain.test: ${{ matrix.javaVersion }}
         with:
           arguments: clean test --stacktrace --no-daemon --parallel --max-workers=1

buildSrc/src/main/kotlin/org/jetbrains/DokkaBuildProperties.kt

@@ -0,0 +1,53 @@
+package org.jetbrains
+
+import org.gradle.api.provider.Provider
+import org.gradle.api.provider.ProviderFactory
+import org.gradle.jvm.toolchain.JavaLanguageVersion
+import org.jetbrains.kotlin.gradle.dsl.KotlinVersion
+import javax.inject.Inject
+
+/**
+ * Common build properties used to build Dokka subprojects.
+ *
+ * This is an extension created by the [org.jetbrains.conventions.Base_gradle] convention plugin.
+ *
+ * Default values are set in the root `gradle.properties`, and can be overridden via
+ * [CLI args, system properties, and environment variables](https://docs.gradle.org/current/userguide/build_environment.html#sec:project_properties)
+ */
+abstract class DokkaBuildProperties @Inject constructor(
+    private val providers: ProviderFactory,
+) {
+
+    /**
+     * The main version of Java that should be used to build Dokka source code.
+     *
+     * Updating the Java target is a breaking change.
+     */
+    val mainJavaVersion: Provider<JavaLanguageVersion> =
+        dokkaProperty("javaToolchain.mainCompiler") { JavaLanguageVersion.of(it) }
+
+    /**
+     * The version of Java that should be used to run Dokka tests.
+     *
+     * This value is set in CI/CD environments to make sure that Dokka still works with different
+     * versions of Java.
+     */
+    val testJavaLauncherVErsion: Provider<JavaLanguageVersion> =
+        dokkaProperty("javaToolchain.testLauncher") { JavaLanguageVersion.of(it) }
+
+    /**
+     * The Kotlin language level that Dokka artifacts are compiled to support.
+     *
+     * Updating the language level is a breaking change.
+     */
+    val kotlinLanguageLevel: Provider<KotlinVersion> =
+        dokkaProperty("kotlinLanguageLevel") { KotlinVersion.fromVersion(it) }
+
+
+    private fun <T : Any> dokkaProperty(name: String, convert: (String) -> T) =
+        providers.gradleProperty("org.jetbrains.dokka.$name").map(convert)
+
+    companion object {
+        const val EXTENSION_NAME = "dokkaBuild"
+    }
+}

buildSrc/src/main/kotlin/org/jetbrains/conventions/base-java.gradle.kts

@@ -8,15 +8,22 @@ package org.jetbrains.conventions
  */
 
 plugins {
+    id("org.jetbrains.conventions.base")
     `java`
 }
 
 java {
     toolchain {
-        languageVersion.set(JavaLanguageVersion.of(8))
+        languageVersion.set(dokkaBuild.mainJavaVersion)
     }
 }
 
 java {
     withSourcesJar()
 }
+
+tasks.withType<Test>().configureEach {
+    javaLauncher.set(javaToolchains.launcherFor {
+        languageVersion.set(dokkaBuild.testJavaLauncherVErsion)
+    })
+}

buildSrc/src/main/kotlin/org/jetbrains/conventions/base.gradle.kts

@@ -1,10 +1,20 @@
 package org.jetbrains.conventions
 
+import org.jetbrains.DokkaBuildProperties
+
+/**
+ * A convention plugin that sets up common config and sensible defaults for all subprojects.
+ *
+ * It provides the [DokkaBuildProperties] extension, for accessing common build properties.
+ */
+
 plugins {
     base
 }
 
-// common Gradle configuration that should be applied to all projects
+val dokkaBuildProperties =
+    extensions.create<DokkaBuildProperties>(DokkaBuildProperties.EXTENSION_NAME)
+
 
 if (project != rootProject) {
     project.group = rootProject.group

buildSrc/src/main/kotlin/org/jetbrains/conventions/kotlin-jvm.gradle.kts

@@ -1,7 +1,6 @@
 package org.jetbrains.conventions
 
 import org.jetbrains.configureDokkaVersion
-import org.jetbrains.kotlin.gradle.dsl.KotlinVersion
 import org.jetbrains.kotlin.gradle.tasks.KotlinCompile
 
 plugins {
@@ -12,8 +11,6 @@ plugins {
 
 configureDokkaVersion()
 
-val language_version: String by project
-
 tasks.withType<KotlinCompile>().configureEach {
     compilerOptions {
         freeCompilerArgs.addAll(
@@ -26,7 +23,7 @@ tasks.withType<KotlinCompile>().configureEach {
             )
         )
         allWarningsAsErrors.set(true)
-        languageVersion.set(KotlinVersion.fromVersion(language_version))
-        apiVersion.set(KotlinVersion.fromVersion(language_version))
+        languageVersion.set(dokkaBuild.kotlinLanguageLevel)
+        apiVersion.set(dokkaBuild.kotlinLanguageLevel)
     }
 }

buildSrc/src/main/kotlin/org/jetbrains/internal/accessors.kt

@@ -0,0 +1,25 @@
+package org.gradle.kotlin.dsl
+
+import org.gradle.api.Project
+import org.jetbrains.DokkaBuildProperties
+
+/*
+ * Utility functions for accessing Gradle extensions that are created by convention plugins.
+ *
+ * (Gradle can't generate the nice DSL accessors for the project that defines them)
+ *
+ * These functions should be marked `internal`, because they are not needed outside of the
+ * convention plugins project.
+ */
+
+/**
+ * Retrieves the [dokkaBuild][org.jetbrains.DokkaBuildProperties] extension.
+ */
+internal val Project.dokkaBuild: DokkaBuildProperties
+    get() = extensions.getByType<DokkaBuildProperties>()
+
+/**
+ * Configures the [dokkaBuild][org.jetbrains.DokkaBuildProperties] extension.
+ */
+internal fun Project.dokkaBuild(configure: DokkaBuildProperties.() -> Unit) =
+    extensions.configure<DokkaBuildProperties>(configure)

gradle.properties

@@ -1,5 +1,8 @@
 # Project Settings
 dokka_version=1.8.20-SNAPSHOT
+org.jetbrains.dokka.javaToolchain.mainCompiler=8
+org.jetbrains.dokka.javaToolchain.testLauncher=8
+org.jetbrains.dokka.kotlinLanguageLevel=1.4
 dokka_integration_test_parallelism=2
 # Versions
 kotlin_version=1.8.10
@@ -8,7 +11,6 @@ kotlinx_html_version=0.7.5
 kotlin_plugin_version=213-1.8.10-release-430-IJ6777.52
 jsoup_version=1.15.3
 idea_version=213.6777.52
-language_version=1.4
 # jackson 2.13.X does not support kotlin language version 1.4, check before updating
 jackson_version=2.12.7
 # fixes CVE-2022-42003