Move JDK toolchain, Kotlin language and JVM target configuration to convention plugin.

Also trying to keep libs.versions.toml ordered alphabetically.

RELNOTES=N/A
PiperOrigin-RevId: 711866498

Author: danysantiago

buildSrc/build.gradle.kts

@@ -1,12 +1,23 @@
 plugins {
-    alias(libs.plugins.kotlinJvm)
+    `kotlin-dsl`
 }
 
 kotlin {
-    jvmToolchain(18)
+    jvmToolchain {
+        languageVersion.set(libs.versions.jdk.map(JavaLanguageVersion::of))
+    }
 }
 
 dependencies {
     implementation(gradleApi())
     implementation(libs.kotlin.gradlePlugin)
 }
+
+gradlePlugin {
+    plugins {
+        register("kotlinJvm") {
+            id = libs.plugins.dagger.kotlinJvm.get().pluginId
+            implementationClass = "dagger.gradle.build.KotlinJvmConventionPlugin"
+        }
+    }
+}

buildSrc/src/main/kotlin/dagger/gradle/build/KotlinJvmConventionPlugin.kt

@@ -0,0 +1,48 @@
+/*
+ * Copyright (C) 2025 The Dagger Authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package dagger.gradle.build
+
+import org.gradle.api.Plugin
+import org.gradle.api.Project
+import org.jetbrains.kotlin.gradle.dsl.KotlinJvmProjectExtension
+import org.jetbrains.kotlin.gradle.dsl.KotlinVersion
+import org.jetbrains.kotlin.gradle.dsl.JvmTarget
+import org.gradle.jvm.toolchain.JavaLanguageVersion
+
+class KotlinJvmConventionPlugin : Plugin<Project> {
+
+    override fun apply(project: Project) {
+        project.pluginManager.apply(KGP_JVM_ID)
+
+        project.plugins.withId(KGP_JVM_ID) {
+            val kotlinProject = project.extensions.getByName("kotlin") as KotlinJvmProjectExtension
+            kotlinProject.explicitApi()
+            kotlinProject.jvmToolchain {
+                languageVersion.set(JavaLanguageVersion.of(project.getVersionByName("jdk")))
+            }
+            kotlinProject.compilerOptions.apply {
+                languageVersion.set(KotlinVersion.fromVersion(project.getVersionByName("kotlinTarget")))
+                apiVersion.set(KotlinVersion.fromVersion(project.getVersionByName("kotlinTarget")))
+                jvmTarget.set(JvmTarget.fromTarget(project.getVersionByName("jvmTarget")))
+            }
+        }
+    }
+
+    companion object {
+        private const val KGP_JVM_ID = "org.jetbrains.kotlin.jvm"
+    }
+}

buildSrc/src/main/kotlin/dagger/gradle/build/VersionCatalogs.kt

@@ -0,0 +1,33 @@
+/*
+ * Copyright (C) 2025 The Dagger Authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package dagger.gradle.build
+
+import org.gradle.api.Project
+import org.gradle.api.artifacts.VersionCatalog
+import org.gradle.api.artifacts.VersionCatalogsExtension
+
+internal val Project.versionCatalog: VersionCatalog
+    get() = project.extensions.getByType(VersionCatalogsExtension::class.java).find("libs").get()
+
+internal fun Project.getVersionByName(name: String): String {
+    val version = versionCatalog.findVersion(name)
+    return if (version.isPresent) {
+        version.get().requiredVersion
+    } else {
+        error("Could not find a version for `$name`")
+    }
+}

gradle-projects/dagger-runtime/build.gradle.kts

@@ -1,9 +1,7 @@
 import dagger.gradle.build.daggerSources
-import org.jetbrains.kotlin.gradle.dsl.JvmTarget
-import org.jetbrains.kotlin.gradle.dsl.KotlinVersion
 
 plugins {
-    id(libs.plugins.kotlinJvm.get().pluginId)
+    alias(libs.plugins.dagger.kotlinJvm)
 }
 
 // TODO(danysantiago): Add proguard files as META-INF resources
@@ -24,16 +22,6 @@ daggerSources {
     )
 }
 
-// TODO(danysantiago): Move configuration to a buildSrc plugin so it is applied to all projects
-kotlin {
-    jvmToolchain(18)
-    compilerOptions {
-        languageVersion = KotlinVersion.KOTLIN_1_8
-        apiVersion = KotlinVersion.KOTLIN_1_8
-        jvmTarget = JvmTarget.JVM_1_8
-    }
-}
-
 dependencies {
     api(libs.javax.inject)
     api(libs.jakarta.inject)

gradle/libs.versions.toml

@@ -1,18 +1,22 @@
 [versions]
-kotlin = "2.0.21"
 guava = "33.0.0-jre"
+jdk = "18"
 junit = "4.13"
+jvmTarget = "1.8"
+kotlin = "2.0.21"
+kotlinTarget = "1.9"
 truth = "1.4.0"
 
 [libraries]
-kotlin-gradlePlugin = { module = "org.jetbrains.kotlin:kotlin-gradle-plugin", version.ref = "kotlin" }
-kotlin-stdlib = { module = "org.jetbrains.kotlin:kotlin-stdlib", version.ref = "kotlin" }
+guava-jre = { module = "com.google.guava:guava", version.ref = "guava" }
 jakarta-inject = { module = "jakarta.inject:jakarta.inject-api", version = "2.0.1" }
 javax-inject = { module = "javax.inject:javax.inject", version = "1" }
 jspecify = { module = "org.jspecify:jspecify", version = "1.0.0" }
-guava-jre = { module = "com.google.guava:guava", version.ref = "guava" }
 junit = { module = "junit:junit", version.ref = "junit" }
+kotlin-gradlePlugin = { module = "org.jetbrains.kotlin:kotlin-gradle-plugin", version.ref = "kotlin" }
+kotlin-stdlib = { module = "org.jetbrains.kotlin:kotlin-stdlib", version.ref = "kotlin" }
 truth = { module = "com.google.truth:truth", version.ref = "truth" }
 
 [plugins]
+dagger-kotlinJvm = { id = "dagger.gradle.build.jvm" }
 kotlinJvm = { id = "org.jetbrains.kotlin.jvm", version.ref = "kotlin" }