Fix test runtime Java versions (#2918)

Fixes #2917 

Co-authored-by: Goooler <wangzongler@gmail.com>

5 files changed, 118 insertions, 7 deletions

diff --git a/build-logic/src/main/kotlin/org/jetbrains/DokkaBuildProperties.kt b/build-logic/src/main/kotlin/org/jetbrains/DokkaBuildProperties.kt
new file mode 100644
index 00000000..57e20acd
--- /dev/null
+++ b/build-logic/src/main/kotlin/org/jetbrains/DokkaBuildProperties.kt
@@ -0,0 +1,54 @@
+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)
+
+    /**
+     * 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)
+            .orElse(mainJavaVersion)
+
+    /**
+     * 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)
+
+
+    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"
+    }
+}
diff --git a/build-logic/src/main/kotlin/org/jetbrains/conventions/base-java.gradle.kts b/build-logic/src/main/kotlin/org/jetbrains/conventions/base-java.gradle.kts
index 2073f9a2..befec76f 100644
--- a/build-logic/src/main/kotlin/org/jetbrains/conventions/base-java.gradle.kts
+++ b/build-logic/src/main/kotlin/org/jetbrains/conventions/base-java.gradle.kts
@@ -8,15 +8,39 @@ 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 {
+    useJUnitPlatform()
+
+    javaLauncher.set(javaToolchains.launcherFor {
+        languageVersion.set(dokkaBuild.testJavaLauncherVersion)
+    })
+}
+
+dependencies {
+    testImplementation(platform("org.junit:junit-bom:5.9.2"))
+    // TODO Upgrade all subprojects to use JUnit Jupiter https://github.com/Kotlin/dokka/issues/2924
+    //      Replace these dependencies with `testImplementation("org.junit.jupiter:junit-jupiter:5.9.2")`
+    //      See https://junit.org/junit5/docs/current/user-guide/#running-tests-build-gradle-engines-configure
+    // Ideally convention plugins should only provide sensible defaults that can be overridden by subprojects.
+    // If a convention plugin defines dependencies, these cannot be easily overridden by subprojects, and so
+    // this should be avoided. However, for now , both JUnit 4 and 5 must be supported, and since these are test
+    // runtime-only dependencies they are not going to have a significant impact subprojects.
+    // These dependencies should be revisited in #2924, and (for example) moved to each subproject (which is more
+    // repetitive, but more declarative and clear), or some other solution.
+    testRuntimeOnly("org.junit.jupiter:junit-jupiter-engine")
+    testRuntimeOnly("org.junit.vintage:junit-vintage-engine")
+}
diff --git a/build-logic/src/main/kotlin/org/jetbrains/conventions/base.gradle.kts b/build-logic/src/main/kotlin/org/jetbrains/conventions/base.gradle.kts
index c4352d16..a1f6e288 100644
--- a/build-logic/src/main/kotlin/org/jetbrains/conventions/base.gradle.kts
+++ b/build-logic/src/main/kotlin/org/jetbrains/conventions/base.gradle.kts
@@ -1,10 +1,19 @@
 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: DokkaBuildProperties = extensions.create(DokkaBuildProperties.EXTENSION_NAME)
+
 
 if (project != rootProject) {
     project.group = rootProject.group
diff --git a/build-logic/src/main/kotlin/org/jetbrains/conventions/kotlin-jvm.gradle.kts b/build-logic/src/main/kotlin/org/jetbrains/conventions/kotlin-jvm.gradle.kts
index c40ce57c..c07fc092 100644
--- a/build-logic/src/main/kotlin/org/jetbrains/conventions/kotlin-jvm.gradle.kts
+++ b/build-logic/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)
     }
 }
diff --git a/build-logic/src/main/kotlin/org/jetbrains/internal/gradleKotlinDslAccessors.kt b/build-logic/src/main/kotlin/org/jetbrains/internal/gradleKotlinDslAccessors.kt
new file mode 100644
index 00000000..78bbc568
--- /dev/null
+++ b/build-logic/src/main/kotlin/org/jetbrains/internal/gradleKotlinDslAccessors.kt
@@ -0,0 +1,27 @@
+@file:Suppress("PackageDirectoryMismatch")
+
+package org.gradle.kotlin.dsl // for convenience use a default package for gradle.kts scripts
+
+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 are not needed outside the convention plugins project and should be marked as
+ * `internal`
+ */
+
+/**
+ * Retrieves the [dokkaBuild][org.jetbrains.DokkaBuildProperties] extension.
+ */
+internal val Project.dokkaBuild: DokkaBuildProperties
+    get() = extensions.getByType()
+
+/**
+ * Configures the [dokkaBuild][org.jetbrains.DokkaBuildProperties] extension.
+ */
+internal fun Project.dokkaBuild(configure: DokkaBuildProperties.() -> Unit) =
+    extensions.configure(configure)