Changes in the compiler needed to run KAPT 4 (KT-51982)

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

@@ -77,9 +77,7 @@ private fun switchToFallbackModeIfNecessary(arguments: CommonCompilerArguments,
             arguments.skipPrereleaseCheck = 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.")
     }
 }
 

compiler/cli/src/org/jetbrains/kotlin/cli/jvm/K2JVMCompiler.kt

@@ -142,7 +142,7 @@ class K2JVMCompiler : CLICompiler<K2JVMCompilerArguments>() {
             val targetDescription = chunk.map { input -> input.getModuleName() + "-" + input.getModuleType() }.let { names ->
                 names.singleOrNull() ?: names.joinToString()
             }
-            if (configuration.getBoolean(CommonConfigurationKeys.USE_FIR) && configuration.getBoolean(CommonConfigurationKeys.USE_LIGHT_TREE))  {
+            if (configuration.getBoolean(CommonConfigurationKeys.USE_FIR) && configuration.getBoolean(CommonConfigurationKeys.USE_LIGHT_TREE)) {
                 val projectEnvironment =
                     createProjectEnvironment(configuration, rootDisposable, EnvironmentConfigFiles.JVM_CONFIG_FILES, messageCollector)
 

compiler/cli/src/org/jetbrains/kotlin/cli/jvm/compiler/FirKotlinToJvmBytecodeCompiler.kt

@@ -30,6 +30,7 @@ import org.jetbrains.kotlin.fir.backend.*
 import org.jetbrains.kotlin.fir.backend.jvm.*
 import org.jetbrains.kotlin.fir.declarations.FirFile
 import org.jetbrains.kotlin.fir.declarations.FirSimpleFunction
+import org.jetbrains.kotlin.fir.extensions.FirAnalysisHandlerExtension
 import org.jetbrains.kotlin.fir.extensions.FirExtensionRegistrar
 import org.jetbrains.kotlin.fir.pipeline.*
 import org.jetbrains.kotlin.fir.session.*
@@ -90,6 +91,10 @@ object FirKotlinToJvmBytecodeCompiler {
 
         // TODO: run lowerings for all modules in the chunk, then run codegen for all modules.
         val project = (projectEnvironment as? VfsBasedProjectEnvironment)?.project
+        if (project != null) {
+            FirAnalysisHandlerExtension.analyze(project, projectConfiguration)?.let { return it }
+        }
+
         for (module in chunk) {
             val moduleConfiguration = projectConfiguration.applyModuleProperties(module, buildFile)
             val context = CompilationContext(

compiler/cli/src/org/jetbrains/kotlin/cli/jvm/compiler/pipeline/compilerPipeline.kt

@@ -47,6 +47,7 @@ import org.jetbrains.kotlin.fir.backend.Fir2IrConfiguration
 import org.jetbrains.kotlin.fir.backend.jvm.FirJvmBackendClassResolver
 import org.jetbrains.kotlin.fir.backend.jvm.FirJvmBackendExtension
 import org.jetbrains.kotlin.fir.backend.jvm.JvmFir2IrExtensions
+import org.jetbrains.kotlin.fir.extensions.FirAnalysisHandlerExtension
 import org.jetbrains.kotlin.fir.extensions.FirExtensionRegistrar
 import org.jetbrains.kotlin.fir.pipeline.FirResult
 import org.jetbrains.kotlin.fir.pipeline.buildResolveAndCheckFirViaLightTree
@@ -87,6 +88,9 @@ fun compileModulesUsingFrontendIrAndLightTree(
 
     performanceManager?.notifyCompilerInitialized(0, 0, targetDescription)
 
+    val project = projectEnvironment.project
+    FirAnalysisHandlerExtension.analyze(project, compilerConfiguration)?.let { return it }
+
     val outputs = mutableListOf<GenerationState>()
     var mainClassFqName: FqName? = null
 
@@ -509,7 +513,7 @@ private fun VirtualFileSystem.findJarRoot(file: File): VirtualFile? =
     findFileByPath("$file${URLUtil.JAR_SEPARATOR}")
 
 private fun VirtualFileSystem.findExistingRoot(
-    root: JvmContentRoot, rootDescription: String, messageCollector: MessageCollector
+    root: JvmContentRoot, rootDescription: String, messageCollector: MessageCollector,
 ): VirtualFile? {
     return findFileByPath(root.file.absolutePath).also {
         if (it == null) {

compiler/frontend.common.jvm/src/org/jetbrains/kotlin/fir/extensions/FirAnalysisHandlerExtension.kt

@@ -5,6 +5,7 @@
 
 package org.jetbrains.kotlin.fir.extensions
 
+import com.intellij.openapi.project.Project
 import org.jetbrains.kotlin.config.CompilerConfiguration
 import org.jetbrains.kotlin.extensions.ProjectExtensionDescriptor
 
@@ -13,7 +14,22 @@ abstract class FirAnalysisHandlerExtension {
     companion object : ProjectExtensionDescriptor<FirAnalysisHandlerExtension>(
         "org.jetbrains.kotlin.fir.firAnalyzeCompleteHandlerExtension",
         FirAnalysisHandlerExtension::class.java
-    )
+    ) {
+        /**
+         * Applies [FirAnalysisHandlerExtension] instances to a project
+         * @receiver the project to analyze
+         * @param configuration compiler configuration
+         * @return [null] if no applicable extensions were found, [true] if all applicable extensions returned [true] from [doAnalysis],
+         * [false] if any applicable extension returned [false]
+         *
+         * @see FirAnalysisHandlerExtension.isApplicable
+         * @see FirAnalysisHandlerExtension.doAnalysis
+         */
+        fun analyze(project: Project, configuration: CompilerConfiguration): Boolean? {
+            val extensions = FirAnalysisHandlerExtension.getInstances(project).filter { it.isApplicable(configuration) }
+            return if (extensions.isEmpty()) null else extensions.all { it.doAnalysis(configuration) }
+        }
+    }
 
     /**
      * Checks whether [doAnalysis] should be called
@@ -25,7 +41,8 @@ abstract class FirAnalysisHandlerExtension {
     /**
      * Performs code analysis
      * @param configuration compiler configuration
-     * @return true if analysis completed successfully. There can be different causes of failure, an incorrect configuration for example.
+     * @return [true] if analysis completed successfully, [false] otherwise.
+     * There can be different causes of failure, an incorrect configuration for example.
      * A failure means that there's no reason to continue building the project.
      */
     abstract fun doAnalysis(configuration: CompilerConfiguration): Boolean