Bump Protobuf and its Gradle plugin

base/src/main/kotlin/io/spine/protobuf/ProtoConverter.kt

@@ -86,8 +86,9 @@ internal abstract class ProtoConverter<M : Message, T : Any> : Converter<M, T>()
                 converter = BytesConverter()
             } else if (isProtoEnum(type)) {
                 @Suppress("UNCHECKED_CAST")
-                val enumType = asProtoEnum(type) as Class<out Enum<out ProtocolMessageEnum>>
-                converter = EnumConverter(enumType)
+                val enumType = type as Class<out ProtocolMessageEnum>
+                @Suppress("UNCHECKED_CAST")
+                converter = EnumConverter(enumType as Class<Nothing>)
             } else if (List::class.java.isAssignableFrom(type)) {
                 converter = ListConverter()
             } else if (Map::class.java.isAssignableFrom(type)) {
@@ -108,13 +109,6 @@ internal abstract class ProtoConverter<M : Message, T : Any> : Converter<M, T>()
             return Enum::class.java.isAssignableFrom(type)
                     && ProtocolMessageEnum::class.java.isAssignableFrom(type)
         }
-
-        @Suppress("UNCHECKED_CAST") // Checked at runtime.
-        private fun <T : Any> asProtoEnum(
-            type: Class<T>
-        ): Class<out Enum<*>> {
-            return type as Class<out Enum<*>>
-        }
     }
 }
 

base/src/main/kotlin/io/spine/string/CharSequenceExts.kt

@@ -117,7 +117,7 @@ private fun CharSequence.doReplace(replacementFn: (s: Separator) -> String): Str
             if (prevEntry == null) {
                 append(s.substring(0, range.first))
             } else {
-                append(s.substring(prevEntry!!.key.last + 1, range.first))
+                append(s.substring(prevEntry.key.last + 1, range.first))
             }
             val replacement = replacementFn.invoke(separator)
             append(replacement)

buildSrc/build.gradle.kts

@@ -75,15 +75,15 @@ val grGitVersion = "4.1.1"
  * This version may change from the [version of Kotlin][io.spine.dependency.lib.Kotlin.version]
  * used by the project.
  */
-val kotlinEmbeddedVersion = "2.2.21"
+val kotlinEmbeddedVersion = "2.3.10"
 
 /**
  * The version of Guava used in `buildSrc`.
  *
  * Always use the same version as the one specified in [io.spine.dependency.lib.Guava].
  * Otherwise, when testing Gradle plugins, clashes may occur.
  */
-val guavaVersion = "33.4.8-jre"
+val guavaVersion = "33.5.0-jre"
 
 /**
  * The version of ErrorProne Gradle plugin.
@@ -103,7 +103,7 @@ val errorPronePluginVersion = "4.2.0"
  * @see <a href="https://github.com/google/protobuf-gradle-plugin/releases">
  *     Protobuf Gradle Plugins Releases</a>
  */
-val protobufPluginVersion = "0.9.5"
+val protobufPluginVersion = "0.9.6"
 
 /**
  * The version of Dokka Gradle Plugins.

buildSrc/src/main/kotlin/io/spine/dependency/lib/Kotlin.kt

@@ -39,7 +39,7 @@ object Kotlin : DependencyWithBom() {
      * depend on Gradle and the version of embedded Kotlin.
      */
     @Suppress("MemberVisibilityCanBePrivate") // used directly from the outside.
-    const val runtimeVersion = "2.2.21"
+    const val runtimeVersion = "2.3.10"
 
     override val version = runtimeVersion
     override val group = "org.jetbrains.kotlin"

buildSrc/src/main/kotlin/io/spine/dependency/lib/Protobuf.kt

@@ -33,7 +33,7 @@ package io.spine.dependency.lib
 )
 object Protobuf {
     const val group = "com.google.protobuf"
-    const val version = "4.33.2"
+    const val version = "4.34.0"
 
     /**
      * The Java library with Protobuf data types.
@@ -64,7 +64,7 @@ object Protobuf {
          *
          * When changing the version, also change the version used in the `build.gradle.kts`.
          */
-        const val version = "0.9.5"
+        const val version = "0.9.6"
         const val id = "com.google.protobuf"
         const val lib = "$group:protobuf-gradle-plugin:$version"
     }

buildSrc/src/main/kotlin/io/spine/gradle/kotlin/KotlinConfig.kt

@@ -28,7 +28,9 @@ package io.spine.gradle.kotlin
 
 import org.gradle.jvm.toolchain.JavaLanguageVersion
 import org.jetbrains.kotlin.gradle.dsl.KotlinCommonCompilerOptions
+import org.jetbrains.kotlin.gradle.dsl.KotlinJvmCompilerOptions
 import org.jetbrains.kotlin.gradle.dsl.KotlinJvmProjectExtension
+import org.jetbrains.kotlin.gradle.dsl.JvmDefaultMode
 
 /**
  * Sets [Java toolchain](https://kotlinlang.org/docs/gradle.html#gradle-java-toolchains-support)
@@ -53,10 +55,12 @@ fun KotlinJvmProjectExtension.applyJvmToolchain(version: String) =
  */
 @Suppress("unused")
 fun KotlinCommonCompilerOptions.setFreeCompilerArgs() {
+    if (this is KotlinJvmCompilerOptions) {
+        jvmDefault.set(JvmDefaultMode.ENABLE)
+    }
     freeCompilerArgs.addAll(
         listOf(
             "-Xskip-prerelease-check",
-            "-Xjvm-default=all",
             "-Xinline-classes",
             "-Xexpect-actual-classes",
             "-Xcontext-parameters",

buildSrc/src/main/kotlin/io/spine/gradle/testing/Logging.kt

@@ -28,9 +28,9 @@ package io.spine.gradle.testing
 
 import org.gradle.api.tasks.testing.Test
 import org.gradle.api.tasks.testing.TestDescriptor
+import org.gradle.api.tasks.testing.TestListener
 import org.gradle.api.tasks.testing.TestResult
 import org.gradle.api.tasks.testing.logging.TestExceptionFormat
-import org.gradle.kotlin.dsl.KotlinClosure2
 
 /**
  * Configures logging of this [Test] task.
@@ -70,19 +70,16 @@ fun Test.configureLogging() {
         >> $skippedTestCount skipped
         """
 
-    afterSuite(
-
-        // `GroovyInteroperability` is employed as `afterSuite()` has no equivalent in Kotlin DSL.
-        // See issue: https://github.com/gradle/gradle/issues/5431
-
-        KotlinClosure2<TestDescriptor, TestResult, Unit>({ descriptor, result ->
+    val listener = object : TestListener {
 
+        override fun afterSuite(descriptor: TestDescriptor, result: TestResult) {
             // If the descriptor has no parent, then it is the root test suite,
             // i.e. it includes the info about all the run tests.
-
             if (descriptor.parent == null) {
                 logger.lifecycle(result.summary())
             }
-        })
-    )
+        }
+    }
+
+    addTestListener(listener)
 }