Enable FIR plugin in SerializationComponentRegistrar

so real projects can be built with K2 and serialization.

Correctly register renderer for serialization plugin errors.

plugins/kotlinx-serialization/kotlinx-serialization.cli/src/org/jetbrains/kotlinx/serialization/compiler/extensions/SerializationComponentRegistrar.kt

@@ -14,6 +14,7 @@ import org.jetbrains.kotlin.container.StorageComponentContainer
 import org.jetbrains.kotlin.container.useInstance
 import org.jetbrains.kotlin.descriptors.ModuleDescriptor
 import org.jetbrains.kotlin.extensions.StorageComponentContainerContributor
+import org.jetbrains.kotlin.fir.extensions.FirExtensionRegistrarAdapter
 import org.jetbrains.kotlin.js.translate.extensions.JsSyntheticTranslateExtension
 import org.jetbrains.kotlin.library.metadata.KlibMetadataSerializerProtocol
 import org.jetbrains.kotlin.metadata.jvm.deserialization.JvmProtoBufUtil
@@ -23,6 +24,7 @@ import org.jetbrains.kotlin.serialization.DescriptorSerializerPlugin
 import org.jetbrains.kotlin.serialization.js.JsSerializerProtocol
 import org.jetbrains.kotlinx.serialization.compiler.diagnostic.SerializationPluginDeclarationChecker
 import org.jetbrains.kotlinx.serialization.compiler.extensions.SerializationConfigurationKeys.DISABLE_INTRINSIC
+import org.jetbrains.kotlinx.serialization.compiler.fir.FirSerializationExtensionRegistrar
 
 object SerializationConfigurationKeys {
     val DISABLE_INTRINSIC: CompilerConfigurationKey<Boolean> =
@@ -57,7 +59,7 @@ class SerializationComponentRegistrar : CompilerPluginRegistrar() {
         if (configuration.get(DISABLE_INTRINSIC) == true) SerializationIntrinsicsState.DISABLED else SerializationIntrinsicsState.NORMAL
 
     override val supportsK2: Boolean
-        get() = false
+        get() = true
 
     companion object {
         fun registerExtensions(extensionStorage: ExtensionStorage, intrinsicsState: SerializationIntrinsicsState = SerializationIntrinsicsState.NORMAL) = with(extensionStorage) {
@@ -76,6 +78,8 @@ class SerializationComponentRegistrar : CompilerPluginRegistrar() {
             IrGenerationExtension.registerExtension(SerializationLoweringExtension(serializationDescriptorSerializer, intrinsicsState))
 
             StorageComponentContainerContributor.registerExtension(SerializationPluginComponentContainerContributor())
+
+            FirExtensionRegistrarAdapter.registerExtension(FirSerializationExtensionRegistrar())
         }
 
         private fun registerProtoExtensions() {

plugins/kotlinx-serialization/kotlinx-serialization.k2/src/org/jetbrains/kotlinx/serialization/compiler/fir/checkers/FirSerializationErrors.kt

@@ -7,6 +7,7 @@ package org.jetbrains.kotlinx.serialization.compiler.fir.checkers
 
 import com.intellij.psi.PsiElement
 import org.jetbrains.kotlin.diagnostics.*
+import org.jetbrains.kotlin.diagnostics.rendering.RootDiagnosticRendererFactory
 import org.jetbrains.kotlin.fir.symbols.impl.FirClassSymbol
 import org.jetbrains.kotlin.fir.symbols.impl.FirRegularClassSymbol
 import org.jetbrains.kotlin.fir.types.ConeKotlinType
@@ -47,4 +48,8 @@ object FirSerializationErrors {
 
     val EXTERNAL_CLASS_NOT_SERIALIZABLE by error2<PsiElement, FirClassSymbol<*>, ConeKotlinType>()
     val EXTERNAL_CLASS_IN_ANOTHER_MODULE by error2<PsiElement, FirClassSymbol<*>, ConeKotlinType>()
+
+    init {
+        RootDiagnosticRendererFactory.registerFactory(KtDefaultErrorMessagesSerialization)
+    }
 }

plugins/kotlinx-serialization/kotlinx-serialization.k2/src/org/jetbrains/kotlinx/serialization/compiler/fir/checkers/KtDefaultErrorMessagesSerialization.kt

@@ -8,16 +8,12 @@ package org.jetbrains.kotlinx.serialization.compiler.fir.checkers
 import org.jetbrains.kotlin.diagnostics.KtDiagnostic
 import org.jetbrains.kotlin.diagnostics.KtDiagnosticFactoryToRendererMap
 import org.jetbrains.kotlin.diagnostics.KtDiagnosticRenderer
+import org.jetbrains.kotlin.diagnostics.rendering.BaseDiagnosticRendererFactory
 import org.jetbrains.kotlin.diagnostics.rendering.CommonRenderers
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirDiagnosticRenderers
 
-object KtDefaultErrorMessagesSerialization {
-    fun getRendererForDiagnostic(diagnostic: KtDiagnostic): KtDiagnosticRenderer {
-        val factory = diagnostic.factory
-        return MAP[factory] ?: factory.ktRenderer
-    }
-
-    val MAP = KtDiagnosticFactoryToRendererMap("Serialization").apply {
+object KtDefaultErrorMessagesSerialization : BaseDiagnosticRendererFactory() {
+    override val MAP = KtDiagnosticFactoryToRendererMap("Serialization").apply {
         put(
             FirSerializationErrors.INLINE_CLASSES_NOT_SUPPORTED,
             "Inline classes require runtime serialization library version at least {0}, while your classpath has {1}.",

plugins/kotlinx-serialization/tests/org/jetbrains/kotlinx/serialization/serializationConfiguration.kt

@@ -36,7 +36,6 @@ class SerializationEnvironmentConfigurator(
         configuration: CompilerConfiguration
     ) {
         SerializationComponentRegistrar.registerExtensions(this, SerializationIntrinsicsState.FORCE_ENABLED)
-        FirExtensionRegistrarAdapter.registerExtension(FirSerializationExtensionRegistrar())
     }
 }