Deprecate ClassBuilderInterceptorExtension

ClassGeneratorExtension is supposed to be used instead.

compiler/backend/src/org/jetbrains/kotlin/codegen/extensions/ClassBuilderInterceptorExtension.kt

@@ -14,6 +14,8 @@
  * limitations under the License.
  */
 
+@file:Suppress("DEPRECATION_ERROR")
+
 package org.jetbrains.kotlin.codegen.extensions
 
 import org.jetbrains.kotlin.codegen.ClassBuilderFactory
@@ -21,6 +23,12 @@ import org.jetbrains.kotlin.diagnostics.DiagnosticSink
 import org.jetbrains.kotlin.extensions.ProjectExtensionDescriptor
 import org.jetbrains.kotlin.resolve.BindingContext
 
+@Deprecated(
+    "This extension is only supported in K1 and will not work properly in K2. " +
+            "Please migrate to org.jetbrains.kotlin.backend.common.extensions.IrGenerationExtension or " +
+            "org.jetbrains.kotlin.backend.jvm.extensions.ClassGeneratorExtension.",
+    level = DeprecationLevel.ERROR
+)
 interface ClassBuilderInterceptorExtension {
     companion object : ProjectExtensionDescriptor<ClassBuilderInterceptorExtension>(
             "org.jetbrains.kotlin.classBuilderFactoryInterceptorExtension", ClassBuilderInterceptorExtension::class.java)
@@ -31,4 +39,4 @@ interface ClassBuilderInterceptorExtension {
             diagnostics: DiagnosticSink
     ): ClassBuilderFactory
 
-}
+}

compiler/backend/src/org/jetbrains/kotlin/codegen/state/GenerationState.kt

@@ -12,7 +12,6 @@ import org.jetbrains.kotlin.codegen.*
 import org.jetbrains.kotlin.codegen.binding.CodegenBinding
 import org.jetbrains.kotlin.codegen.context.CodegenContext
 import org.jetbrains.kotlin.codegen.context.RootContext
-import org.jetbrains.kotlin.codegen.extensions.ClassBuilderInterceptorExtension
 import org.jetbrains.kotlin.codegen.extensions.ClassFileFactoryFinalizerExtension
 import org.jetbrains.kotlin.codegen.inline.GlobalInlineContext
 import org.jetbrains.kotlin.codegen.inline.InlineCache
@@ -405,14 +404,14 @@ class GenerationState private constructor(
         this.factory = ClassFileFactory(this, interceptedBuilderFactory, finalizers)
     }
 
-    @Suppress("UNCHECKED_CAST")
-    private fun loadClassBuilderInterceptors(): List<ClassBuilderInterceptorExtension> {
+    @Suppress("UNCHECKED_CAST", "DEPRECATION_ERROR")
+    private fun loadClassBuilderInterceptors(): List<org.jetbrains.kotlin.codegen.extensions.ClassBuilderInterceptorExtension> {
         // Using Class.forName here because we're in the old JVM backend, and we need to load extensions declared in the JVM IR backend.
         val adapted = Class.forName("org.jetbrains.kotlin.backend.jvm.extensions.ClassBuilderExtensionAdapter")
             .getDeclaredMethod("getExtensions", Project::class.java)
-            .invoke(null, project) as List<ClassBuilderInterceptorExtension>
+            .invoke(null, project) as List<org.jetbrains.kotlin.codegen.extensions.ClassBuilderInterceptorExtension>
 
-        return ClassBuilderInterceptorExtension.getInstances(project) + adapted
+        return org.jetbrains.kotlin.codegen.extensions.ClassBuilderInterceptorExtension.getInstances(project) + adapted
     }
 
     fun beforeCompile() {

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

@@ -67,7 +67,6 @@ import org.jetbrains.kotlin.cli.jvm.index.*
 import org.jetbrains.kotlin.cli.jvm.javac.JavacWrapperRegistrar
 import org.jetbrains.kotlin.cli.jvm.modules.CliJavaModuleFinder
 import org.jetbrains.kotlin.cli.jvm.modules.CliJavaModuleResolver
-import org.jetbrains.kotlin.codegen.extensions.ClassBuilderInterceptorExtension
 import org.jetbrains.kotlin.codegen.extensions.ClassFileFactoryFinalizerExtension
 import org.jetbrains.kotlin.codegen.extensions.ExpressionCodegenExtension
 import org.jetbrains.kotlin.compiler.plugin.CompilerPluginRegistrar
@@ -637,7 +636,8 @@ class KotlinCoreEnvironment private constructor(
             ExpressionCodegenExtension.registerExtensionPoint(project)
             SyntheticResolveExtension.registerExtensionPoint(project)
             SyntheticJavaResolveExtension.registerExtensionPoint(project)
-            ClassBuilderInterceptorExtension.registerExtensionPoint(project)
+            @Suppress("DEPRECATION_ERROR")
+            org.jetbrains.kotlin.codegen.extensions.ClassBuilderInterceptorExtension.registerExtensionPoint(project)
             ClassGeneratorExtension.registerExtensionPoint(project)
             ClassFileFactoryFinalizerExtension.registerExtensionPoint(project)
             AnalysisHandlerExtension.registerExtensionPoint(project)

compiler/ir/backend.jvm/src/org/jetbrains/kotlin/backend/jvm/extensions/ClassBuilderExtensionAdapter.kt

@@ -12,7 +12,6 @@ import org.jetbrains.kotlin.codegen.ClassBuilder
 import org.jetbrains.kotlin.codegen.ClassBuilderFactory
 import org.jetbrains.kotlin.codegen.DelegatingClassBuilder
 import org.jetbrains.kotlin.codegen.DelegatingClassBuilderFactory
-import org.jetbrains.kotlin.codegen.extensions.ClassBuilderInterceptorExtension
 import org.jetbrains.kotlin.diagnostics.DiagnosticSink
 import org.jetbrains.kotlin.ir.declarations.IrClass
 import org.jetbrains.kotlin.ir.declarations.IrDeclaration
@@ -30,11 +29,14 @@ import org.jetbrains.org.objectweb.asm.RecordComponentVisitor
 @Suppress("unused") // Used reflectively in GenerationState.
 internal object ClassBuilderExtensionAdapter {
     @JvmStatic
-    fun getExtensions(project: Project): List<ClassBuilderInterceptorExtension> =
+    @Suppress("DEPRECATION_ERROR")
+    fun getExtensions(project: Project): List<org.jetbrains.kotlin.codegen.extensions.ClassBuilderInterceptorExtension> =
         ClassGeneratorExtension.getInstances(project).map(::ExtensionAdapter)
 }
 
-private class ExtensionAdapter(private val extension: ClassGeneratorExtension) : ClassBuilderInterceptorExtension {
+@Suppress("DEPRECATION_ERROR")
+private class ExtensionAdapter(private val extension: ClassGeneratorExtension) :
+    org.jetbrains.kotlin.codegen.extensions.ClassBuilderInterceptorExtension {
     override fun interceptClassBuilderFactory(
         interceptedFactory: ClassBuilderFactory,
         bindingContext: BindingContext,