[PowerAssert] Update Gradle extension to be more idiomatic

Instead of using raw List types in the Gradle extension, ListProperty
should be used instead to make it more Gradle idiomatic. Also marking
the extension and all properties as experimental to allow easier
changing in the future.

^KT-65952 Fixed

libraries/tools/kotlin-gradle-plugin-integration-tests/src/test/resources/testProject/powerAssertSimple/build.gradle.kts

@@ -34,15 +34,14 @@ kotlin {
 }
 
 powerAssert {
-    functions = listOf(
+    functions.addAll(
-        "kotlin.assert",
         "kotlin.test.assertTrue",
         "kotlin.require",
         "sample.AssertScope.assert",
         "sample.assert",
         "sample.dbg"
     )
-    excludedSourceSets = listOf(
+    excludedSourceSets.addAll(
         "commonMain",
         "jvmMain",
         "jsMain",

libraries/tools/kotlin-power-assert/src/common/kotlin/org/jetbrains/kotlin/powerassert/gradle/PowerAssertGradleExtension.kt

@@ -19,7 +19,16 @@
 
 package org.jetbrains.kotlin.powerassert.gradle
 
-open class PowerAssertGradleExtension {
+import org.gradle.api.model.ObjectFactory
-    var functions: List<String> = listOf("kotlin.assert")
+import org.gradle.api.provider.ListProperty
-    var excludedSourceSets: List<String> = listOf()
+import org.jetbrains.kotlin.gradle.ExperimentalKotlinGradlePluginApi
+import javax.inject.Inject
+
+@ExperimentalKotlinGradlePluginApi
+abstract class PowerAssertGradleExtension @Inject constructor(
+    objectFactory: ObjectFactory,
+) {
+    val functions: ListProperty<String> = objectFactory.listProperty(String::class.java).convention(listOf("kotlin.assert"))
+
+    val excludedSourceSets: ListProperty<String> = objectFactory.listProperty(String::class.java).convention(emptyList())
 }

libraries/tools/kotlin-power-assert/src/common/kotlin/org/jetbrains/kotlin/powerassert/gradle/PowerAssertGradlePlugin.kt

@@ -21,8 +21,10 @@ package org.jetbrains.kotlin.powerassert.gradle
 
 import org.gradle.api.Project
 import org.gradle.api.provider.Provider
+import org.jetbrains.kotlin.gradle.ExperimentalKotlinGradlePluginApi
 import org.jetbrains.kotlin.gradle.plugin.*
 
+@OptIn(ExperimentalKotlinGradlePluginApi::class)
 class PowerAssertGradlePlugin : KotlinCompilerPluginSupportPlugin {
     companion object {
         private const val POWER_ASSERT_ARTIFACT_NAME = "kotlin-power-assert-compiler-plugin-embeddable"
@@ -37,7 +39,7 @@ class PowerAssertGradlePlugin : KotlinCompilerPluginSupportPlugin {
     override fun isApplicable(kotlinCompilation: KotlinCompilation<*>): Boolean {
         val project = kotlinCompilation.target.project
         val extension = project.extensions.getByType(PowerAssertGradleExtension::class.java)
-        return extension.excludedSourceSets.none { it == kotlinCompilation.defaultSourceSet.name }
+        return extension.excludedSourceSets.get().none { it == kotlinCompilation.defaultSourceSet.name }
     }
 
     override fun applyToCompilation(
@@ -45,8 +47,8 @@ class PowerAssertGradlePlugin : KotlinCompilerPluginSupportPlugin {
     ): Provider<List<SubpluginOption>> {
         val project = kotlinCompilation.target.project
         val extension = project.extensions.getByType(PowerAssertGradleExtension::class.java)
-        return project.provider {
+        return extension.functions.map { functions ->
-            extension.functions.map {
+            functions.map {
                 SubpluginOption(key = FUNCTION_ARG_NAME, value = it)
             }
         }