Added full KMP support for the Gradle Plugin

gradle-conventions/src/main/kotlin/conventions-jvm.gradle.kts

@@ -20,7 +20,10 @@ java {
     withSourcesJar()
 }
 
-configureJavaCompatibility(8)
+if (project.name != "gradle-plugin") {
+    configureJavaCompatibility(8)
+}
+
 configureKotlinCompatibility("2.0.0")
 
 kotlin {

gradle-conventions/src/main/kotlin/util/other/generateSource.kt

@@ -40,20 +40,28 @@ fun Project.generateSource(
     text: String,
     chooseSourceSet: NamedDomainObjectContainer<KotlinSourceSet>.() -> NamedDomainObjectProvider<KotlinSourceSet>,
 ) {
-    val sourcesDir = File(project.layout.buildDirectory.asFile.get(), "generated-sources/kotlin")
-
-    val generatePluginVersionTask =
-        tasks.register<GenerateSourceTask>("generateSources_$name", name, text, sourcesDir)
-
     withKotlinJvmExtension {
-        chooseSourceSet(sourceSets).configure {
-            kotlin.srcDir(generatePluginVersionTask.map { it.sourcesDir })
-        }
+        generateSource(sourceSets, name, text, chooseSourceSet)
     }
 
     withKotlinKmpExtension {
-        chooseSourceSet(sourceSets).configure {
-            kotlin.srcDir(generatePluginVersionTask.map { it.sourcesDir })
-        }
+        generateSource(sourceSets, name, text, chooseSourceSet)
+    }
+}
+
+private fun Project.generateSource(
+    sourceSets: NamedDomainObjectContainer<KotlinSourceSet>,
+    name: String,
+    text: String,
+    chooseSourceSet: NamedDomainObjectContainer<KotlinSourceSet>.() -> NamedDomainObjectProvider<KotlinSourceSet>,
+) {
+    val sourceSet = chooseSourceSet(sourceSets)
+    val sourcesDir = File(project.layout.buildDirectory.asFile.get(), "generated-sources/kotlin/${sourceSet.name}")
+
+    val generatePluginVersionTask =
+        tasks.register<GenerateSourceTask>("generateSources_$name", name, text, sourcesDir)
+
+    sourceSet.configure {
+        kotlin.srcDir(generatePluginVersionTask.map { it.sourcesDir })
     }
 }

gradle-plugin/build.gradle.kts

@@ -5,10 +5,6 @@
 import org.jetbrains.kotlin.gradle.tasks.KotlinCompile
 import util.other.generateSource
 
-/*
- * Copyright 2023-2025 JetBrains s.r.o and contributors. Use of this source code is governed by the Apache 2.0 license.
- */
-
 plugins {
     `kotlin-dsl`
     alias(libs.plugins.conventions.jvm)
@@ -22,7 +18,7 @@ version = rootProject.libs.versions.kotlinx.rpc.get()
 kotlin {
     explicitApi()
 
-    jvmToolchain(11)
+    jvmToolchain(17)
 }
 
 tasks.withType<KotlinCompile>().configureEach {

gradle-plugin/src/main/kotlin/kotlinx/rpc/Extensions.kt

@@ -24,7 +24,7 @@ internal fun Project.rpcExtensionOrNull(): RpcExtension? = extensions.findByType
 internal fun Project.rpcExtension(): RpcExtension = rpcExtensionOrNull()
     ?: error("Rpc extension not found. Please apply the plugin to the project")
 
-public open class RpcExtension @Inject constructor(objects: ObjectFactory, private val project: Project) {
+public open class RpcExtension @Inject constructor(objects: ObjectFactory, project: Project) {
     /**
      * Controls `@Rpc` [annotation type-safety](https://github.com/Kotlin/kotlinx-rpc/pull/240) compile-time checkers.
      *
@@ -48,25 +48,60 @@ public open class RpcExtension @Inject constructor(objects: ObjectFactory, priva
         configure.execute(strict)
     }
 
-    internal val protocApplied = AtomicBoolean(false)
 
     /**
      * Protoc settings.
+     *
+     * Can't be called in a lazy context if not initialized.
      */
-    public val protoc: ProtocExtension by lazy {
-        if (protocApplied.get()) {
-            error("Illegal access to protoc extension during DefaultProtocExtension.init")
+    public val protoc: Provider<ProtocExtension> = project.provider {
+        if (!protocApplied.get()) {
+            error("""
+                Protoc extension was not initialized. 
+                Please, apply the plugin by using the following declaration:
+
+                  rpc {
+                      protoc()
+                  }
+
+                If the error persists, check if you are using this property lazily, 
+                i.e. by calling 'protoc.map { }' and not 'protoc.get()', 
+                otherwise the order of initialization may be wrong.
+            """.trimIndent())
         }
 
-        protocApplied.set(true)
-        objects.newInstance<DefaultProtocExtension>()
+        protocInternal
     }
 
     /**
      * Protoc settings.
      */
     public fun protoc(configure: Action<ProtocExtension> = Action {}) {
-        configure.execute(protoc)
+        configure.execute(protocInternal)
+    }
+
+    internal val protocApplied = AtomicBoolean(false)
+
+    internal val protocInternal by lazy {
+        if (protocApplied.get()) {
+            error("Illegal access to protoc extension during DefaultProtocExtension.init")
+        }
+
+        protocApplied.set(true)
+        objects.newInstance<DefaultProtocExtension>().apply {
+            callbacks.forEach { it.execute(this) }
+        }
+    }
+
+    private val callbacks = mutableListOf<Action<ProtocExtension>>()
+
+    internal fun whenProtocApplied(action: Action<ProtocExtension>) {
+        if (protocApplied.get()) {
+            action.execute(protoc.get())
+            return
+        }
+
+        callbacks.add(action)
     }
 }
 

gradle-plugin/src/main/kotlin/kotlinx/rpc/buf/BufExtensions.kt

@@ -24,7 +24,7 @@ import kotlin.time.Duration
  *
  * @see <a href="https://buf.build/docs/reference/cli/buf/">buf commands</a>
  */
-public open class BufExtension @Inject constructor(objects: ObjectFactory) {
+public open class BufExtension @Inject internal constructor(objects: ObjectFactory) {
     /**
      * `--config` argument value.
      *
@@ -101,17 +101,17 @@ public open class BufExtension @Inject constructor(objects: ObjectFactory) {
 /**
  * Allows registering custom Buf tasks that can operate on the generated workspace.
  */
-public open class BufTasksExtension @Inject constructor(internal val project: Project) {
+public open class BufTasksExtension @Inject internal constructor(internal val project: Project) {
 
     /**
      * Registers a custom Buf task that operates on the generated workspace.
      *
      * Name conventions:
      * `lint` input for [name] will result in tasks
      * named 'bufLintMain' and 'bufLintTest' for Kotlin/JVM projects
-     * and 'bufLintCommonMain' and 'bufLintCommonTest' for Kotlin/Multiplatform projects.
+     * and 'bufLintCommonMain', 'bufLintCommonTest', 'bufLintNativeMain', etc., for Kotlin/Multiplatform projects.
      *
-     * Note the by default 'test' task doesn't depend on 'main' task.
+     * Note the by default 'test' task doesn't depend on the 'main' task.
      */
     public fun <T : BufExecTask> registerWorkspaceTask(
         kClass: KClass<T>,
@@ -129,7 +129,6 @@ public open class BufTasksExtension @Inject constructor(internal val project: Pr
         return provider
     }
 
-
     /**
      * Registers a custom Buf task that operates on the generated workspace.
      *

gradle-plugin/src/main/kotlin/kotlinx/rpc/buf/tasks/BufExecTask.kt

@@ -117,7 +117,7 @@ internal fun <T : BufExecTask> Project.registerBufExecTask(
     bufExecutable.set(executableConfiguration.singleFile)
     this.workingDir.set(workingDir)
 
-    val buf = provider { rpcExtension().protoc.buf }
+    val buf = provider { rpcExtension().protoc.get().buf }
     configFile.set(buf.flatMap { it.configFile })
     logFormat.set(buf.flatMap { it.logFormat })
     bufTimeoutInWholeSeconds.set(buf.flatMap { it.timeout.map { duration -> duration.inWholeSeconds } })

gradle-plugin/src/main/kotlin/kotlinx/rpc/buf/tasks/BufGenerateTask.kt

@@ -131,7 +131,7 @@ internal fun Project.registerBufGenerateTask(
         group = PROTO_GROUP
         description = "Generates code from .proto files using 'buf generate'"
 
-        val generate = provider { rpcExtension().protoc.buf.generate }
+        val generate = provider { rpcExtension().protoc.get().buf.generate }
 
         includeImports.set(generate.flatMap { it.includeImports })
         includeWkt.set(generate.flatMap { it.includeWkt })

gradle-plugin/src/main/kotlin/kotlinx/rpc/buf/tasks/GenerateBufGenYaml.kt

@@ -137,19 +137,13 @@ public abstract class GenerateBufGenYaml : DefaultTask() {
 internal fun Project.registerGenerateBufGenYamlTask(
     name: String,
     buildSourceSetsDir: File,
-    protocPlugins: Provider<List<ProtocPlugin>>,
+    protocPlugins: Provider<Set<ProtocPlugin>>,
     configure: GenerateBufGenYaml.() -> Unit = {},
 ): TaskProvider<GenerateBufGenYaml> {
     val capitalizeName = name.replaceFirstChar { it.uppercase() }
     return project.tasks.register<GenerateBufGenYaml>("${GenerateBufGenYaml.NAME_PREFIX}$capitalizeName") {
         val pluginsProvider = project.provider {
             protocPlugins.get().map { plugin ->
-                if (!plugin.artifact.isPresent) {
-                    throw GradleException(
-                        "Artifact is not specified for protoc plugin ${plugin.name}. " +
-                                "Use `local {}` or `remote {}` to specify it.")
-                }
-
                 val artifact = plugin.artifact.get()
                 val locator = when (artifact) {
                     is ProtocPlugin.Artifact.Local -> artifact.executor.get()

gradle-plugin/src/main/kotlin/kotlinx/rpc/buf/tasks/GenerateBufYaml.kt

@@ -5,11 +5,13 @@
 package kotlinx.rpc.buf.tasks
 
 import kotlinx.rpc.buf.BUF_YAML
+import kotlinx.rpc.protoc.DefaultProtoSourceSet
 import kotlinx.rpc.protoc.PROTO_GROUP
 import kotlinx.rpc.util.ensureRegularFileExists
 import org.gradle.api.DefaultTask
 import org.gradle.api.Project
 import org.gradle.api.provider.Property
+import org.gradle.api.provider.Provider
 import org.gradle.api.tasks.Input
 import org.gradle.api.tasks.OutputFile
 import org.gradle.api.tasks.TaskAction
@@ -88,7 +90,7 @@ internal fun Project.registerGenerateBufYamlTask(
     buildSourceSetsDir: File,
     buildSourceSetsProtoDir: File,
     buildSourceSetsImportDir: File,
-    withImport: Boolean,
+    withImport: Provider<Boolean>,
     configure: GenerateBufYaml.() -> Unit = {},
 ): TaskProvider<GenerateBufYaml> {
     val capitalizeName = name.replaceFirstChar { it.uppercase() }

gradle-plugin/src/main/kotlin/kotlinx/rpc/internal/configureLocalProtocGenDevelopmentDependency.kt

@@ -7,7 +7,6 @@ package kotlinx.rpc.internal
 import kotlinx.rpc.buf.tasks.BufGenerateTask
 import kotlinx.rpc.protoc.grpcKotlinMultiplatform
 import kotlinx.rpc.protoc.kotlinMultiplatform
-import kotlinx.rpc.protoc.protoSourceSets
 import kotlinx.rpc.rpcExtension
 import org.gradle.api.Project
 import org.gradle.internal.extensions.core.extra
@@ -21,9 +20,7 @@ public fun Project.configureLocalProtocGenDevelopmentDependency(
     val globalRootDir: String by extra
 
     // init
-    rpcExtension().protoc()
-
-    protoSourceSets.all {
+    rpcExtension().protoc {
         plugins {
             kotlinMultiplatform {
                 local {