[KAPT4] Create basic infrastructure for KAPT4

compiler/cli/cli-base/src/org/jetbrains/kotlin/cli/jvm/compiler/KotlinCoreEnvironment.kt

@@ -76,6 +76,7 @@ import org.jetbrains.kotlin.extensions.*
 import org.jetbrains.kotlin.extensions.internal.CandidateInterceptor
 import org.jetbrains.kotlin.extensions.internal.InternalNonStableExtensionPoints
 import org.jetbrains.kotlin.extensions.internal.TypeResolutionInterceptor
+import org.jetbrains.kotlin.fir.extensions.FirAnalysisHandlerExtension
 import org.jetbrains.kotlin.fir.extensions.FirExtensionRegistrarAdapter
 import org.jetbrains.kotlin.idea.KotlinFileType
 import org.jetbrains.kotlin.js.translate.extensions.JsSyntheticTranslateExtension
@@ -673,6 +674,7 @@ class KotlinCoreEnvironment private constructor(
             FirExtensionRegistrarAdapter.registerExtensionPoint(project)
             TypeAttributeTranslatorExtension.registerExtensionPoint(project)
             AssignResolutionAltererExtension.registerExtensionPoint(project)
+            FirAnalysisHandlerExtension.registerExtensionPoint(project)
         }
 
         internal fun registerExtensionsFromPlugins(project: MockProject, configuration: CompilerConfiguration) {

compiler/cli/cli-common/gen/org/jetbrains/kotlin/cli/common/arguments/K2JVMCompilerArgumentsCopyGenerated.kt

@@ -78,6 +78,7 @@ fun copyK2JVMCompilerArguments(from: K2JVMCompilerArguments, to: K2JVMCompilerAr
     to.typeEnhancementImprovementsInStrictMode = from.typeEnhancementImprovementsInStrictMode
     to.useFastJarFileSystem = from.useFastJarFileSystem
     to.useJavac = from.useJavac
+    to.useKapt4 = from.useKapt4
     to.useOldBackend = from.useOldBackend
     to.useOldClassFilesReading = from.useOldClassFilesReading
     to.useOldInlineClassesManglingScheme = from.useOldInlineClassesManglingScheme

compiler/cli/cli-common/src/org/jetbrains/kotlin/cli/common/arguments/K2JVMCompilerArguments.kt

@@ -846,6 +846,15 @@ Also sets `-jvm-target` value equal to the selected JDK version"""
             field = value
         }
 
+    @Argument(
+        value = "-Xuse-kapt4",
+        description = "Enable the experimental KAPT 4."
+    )
+    var useKapt4 = false
+        set(value) {
+            checkFrozen()
+            field = value
+        }
 
     override fun configureAnalysisFlags(collector: MessageCollector, languageVersion: LanguageVersion): MutableMap<AnalysisFlag<*>, Any> {
         val result = super.configureAnalysisFlags(collector, languageVersion)

compiler/cli/src/org/jetbrains/kotlin/cli/common/arguments.kt

@@ -56,17 +56,18 @@ fun CompilerConfiguration.setupCommonArguments(
     buildHmppModuleStructure(arguments)?.let { put(CommonConfigurationKeys.HMPP_MODULE_STRUCTURE, it) }
 }
 
-fun switchToFallbackModeIfNecessary(arguments: CommonCompilerArguments, messageCollector: MessageCollector) {
-    val isK2 = arguments.useK2 || (arguments.languageVersion?.startsWith('2') ?: (LanguageVersion.LATEST_STABLE >= LanguageVersion.KOTLIN_2_0))
-    if (isK2) {
-        val isKaptUsed = arguments.pluginOptions?.any { it.startsWith("plugin:org.jetbrains.kotlin.kapt3") } == true
-        if (isKaptUsed) {
-            if (!arguments.suppressVersionWarnings) {
-                messageCollector.report(
-                    CompilerMessageSeverity.STRONG_WARNING,
-                    "Kapt currently doesn't support language version 2.0+.\nFalling back to 1.9."
-                )
-            }
+private fun switchToFallbackModeIfNecessary(arguments: CommonCompilerArguments, messageCollector: MessageCollector) {
+    fun warn(message: String) {
+        if (!arguments.suppressVersionWarnings) messageCollector.report(CompilerMessageSeverity.STRONG_WARNING, message)
+    }
+
+    if (arguments !is K2JVMCompilerArguments) return
+    val isK2 =
+        arguments.useK2 || (arguments.languageVersion?.startsWith('2') ?: (LanguageVersion.LATEST_STABLE >= LanguageVersion.KOTLIN_2_0))
+    val isKaptUsed = arguments.pluginOptions?.any { it.startsWith("plugin:org.jetbrains.kotlin.kapt3") } == true
+    when {
+        isK2 && isKaptUsed && !arguments.useKapt4 -> {
+            warn("Kapt currently doesn't support language version 2.0+. Falling back to 1.9.")
             arguments.languageVersion = LanguageVersion.KOTLIN_1_9.versionString
             if (arguments.apiVersion?.startsWith("2") == true) {
                 arguments.apiVersion = ApiVersion.KOTLIN_1_9.versionString
@@ -74,8 +75,11 @@ fun switchToFallbackModeIfNecessary(arguments: CommonCompilerArguments, messageC
             arguments.useK2 = false
             arguments.skipMetadataVersionCheck = true
             arguments.skipPrereleaseCheck = true
-            (arguments as? K2JVMCompilerArguments)?.allowUnstableDependencies = true
+            arguments.allowUnstableDependencies = true
         }
+        isK2 && isKaptUsed && arguments.useKapt4 -> warn("Kapt 4 is still experimental. Use with caution.")
+        arguments.useKapt4 && !isK2 -> warn("-Xuse-kapt4 flag can be only used with language version 2.0+.")
+        arguments.useKapt4 && !isKaptUsed -> warn("-Xuse-kapt4 flag is present but no Kapt configuration options are provided.")
     }
 }