Allow users to override Kotlin version, fix #367

tools/gradle-plugin/build.gradle.kts

@@ -23,16 +23,18 @@ plugins {
 
 val integTest = sourceSets.create("integTest")
 
+/**
+ * Because we use [compileOnly] for `kotlin-gradle-plugin`, it would be missing
+ * in `plugin-under-test-metadata.properties`. Here we inject the jar into TestKit plugin
+ * classpath via [PluginUnderTestMetadata] to avoid [NoClassDefFoundError].
+ */
+val kotlinVersionForIntegrationTest: Configuration by configurations.creating
+
 dependencies {
     compileOnly(gradleApi())
     compileOnly(gradleKotlinDsl())
-    api(kotlin("gradle-plugin-api").toString()) {
-        exclude("org.jetbrains.kotlin", "kotlin-stdlib")
-    }
-    api(kotlin("gradle-plugin").toString()) {
-        exclude("org.jetbrains.kotlin", "kotlin-stdlib")
-    }
-
+    compileOnly(kotlin("gradle-plugin-api"))
+    compileOnly(kotlin("gradle-plugin"))
     compileOnly(kotlin("stdlib"))
 
     implementation("com.google.code.gson:gson:2.8.6")
@@ -52,6 +54,12 @@ dependencies {
     "integTestImplementation"("org.junit.jupiter:junit-jupiter-engine:${Versions.junit}")
 //    "integTestImplementation"("org.spockframework:spock-core:1.3-groovy-2.5")
     "integTestImplementation"(gradleTestKit())
+
+    kotlinVersionForIntegrationTest(kotlin("gradle-plugin", "1.5.21"))
+}
+
+tasks.named<PluginUnderTestMetadata>("pluginUnderTestMetadata") {
+    pluginClasspath.from(kotlinVersionForIntegrationTest)
 }
 
 version = Versions.console

tools/gradle-plugin/src/integTest/kotlin/KotlinTransitiveDependenciesIntegrationTest.kt

@@ -0,0 +1,56 @@
+/*
+ * Copyright 2019-2021 Mamoe Technologies and contributors.
+ *
+ * 此源代码的使用受 GNU AFFERO GENERAL PUBLIC LICENSE version 3 许可证的约束, 可以在以下链接找到该许可证.
+ * Use of this source code is governed by the GNU AGPLv3 license that can be found through the following link.
+ *
+ * https://github.com/mamoe/mirai/blob/dev/LICENSE
+ */
+
+package net.mamoe.mirai.console.gradle
+
+import org.gradle.testkit.runner.GradleRunner
+import org.junit.jupiter.api.Assertions
+import org.junit.jupiter.api.Test
+import org.junit.jupiter.api.io.TempDir
+import java.io.ByteArrayOutputStream
+import java.io.File
+import java.io.PrintWriter
+
+class KotlinTransitiveDependenciesIntegrationTest {
+    @Test
+    fun `user can override Kotlin plugin version`(@TempDir dir: File) {
+        // We're packaging the plugin with kotlin transitive dependencies > 1.4.30
+        // This is testing that users are free to use different versions
+        val userSpecifiedKotlinPluginVersion = "1.5.21"
+        dir.resolve("settings.gradle").writeText("")
+        dir.resolve("build.gradle").writeText(
+            """
+            plugins {
+                id 'net.mamoe.mirai-console'
+                id 'org.jetbrains.kotlin.jvm' version '$userSpecifiedKotlinPluginVersion'
+            }
+        """.trimIndent()
+        )
+
+        val stdout = ByteArrayOutputStream()
+        val stderr = ByteArrayOutputStream()
+
+        GradleRunner.create()
+            .withProjectDir(dir)
+            .withGradleVersion("6.8.3")
+            .withPluginClasspath()
+            .forwardStdOutput(PrintWriter(stdout))
+            .forwardStdError(PrintWriter(stderr))
+            .withArguments(listOf("dependencies"))
+            .build()
+
+        System.out.println(stdout)
+        System.err.println(stderr)
+
+        Assertions.assertTrue(
+            stdout.toString()
+                .contains("org.jetbrains.kotlin:kotlin-compiler-embeddable:${userSpecifiedKotlinPluginVersion}")
+        )
+    }
+}