Refactor MetadataExtensions.kt to remove extension visitors

This helps to completely get rid of Visitors API during reading and writing
of the JVM metadata.

Note: Klib writers still use .accept and left for future refactorings.

See also #KT-59442

libraries/kotlinx-metadata/jvm/src/kotlinx/metadata/jvm/JvmExtensionVisitors.kt

@@ -2,7 +2,7 @@
  * Copyright 2010-2018 JetBrains s.r.o. and Kotlin Programming Language contributors.
  * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
  */
-@file:Suppress("DEPRECATION_ERROR")
+@file:Suppress("DEPRECATION_ERROR") // delegate implementation
 
 package kotlinx.metadata.jvm
 

libraries/kotlinx-metadata/jvm/src/kotlinx/metadata/jvm/KotlinClassMetadata.kt

@@ -2,7 +2,10 @@
  * Copyright 2010-2023 JetBrains s.r.o. and Kotlin Programming Language contributors.
  * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
  */
-@file:Suppress("DEPRECATION_ERROR", "UNUSED_PARAMETER")
+@file:Suppress(
+    "DEPRECATION_ERROR", // Deprecated .accept implementation
+    "UNUSED_PARAMETER" // For deprecated Writer.write
+)
 
 package kotlinx.metadata.jvm
 

libraries/kotlinx-metadata/jvm/src/kotlinx/metadata/jvm/KotlinModuleMetadata.kt

@@ -5,11 +5,11 @@
 
 @file:Suppress(
     "MemberVisibilityCanBePrivate",
-    "DEPRECATION",
+    "DEPRECATION", // For KmModule.annotations — remove reading when deprecation is raised to error
-    "DEPRECATION_ERROR",
+    "DEPRECATION_ERROR", // deprecated .accept implementation
     "INVISIBLE_MEMBER", // InconsistentKotlinMetadataException
     "INVISIBLE_REFERENCE",
-    "UNUSED_PARAMETER"
+    "UNUSED_PARAMETER" // For deprecated Writer.write
 )
 
 package kotlinx.metadata.jvm

libraries/kotlinx-metadata/jvm/src/kotlinx/metadata/jvm/internal/JvmExtensionNodes.kt

@@ -2,7 +2,7 @@
  * Copyright 2010-2022 JetBrains s.r.o. and Kotlin Programming Language contributors.
  * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
  */
-@file:Suppress("DEPRECATION","DEPRECATION_ERROR")
+@file:Suppress("DEPRECATION","DEPRECATION_ERROR") // inheritance of deprecated visitors will be removed with visitors
 
 package kotlinx.metadata.jvm.internal
 

libraries/kotlinx-metadata/jvm/src/kotlinx/metadata/jvm/internal/JvmMetadataExtensions.kt

@@ -15,272 +15,212 @@ import org.jetbrains.kotlin.metadata.deserialization.getExtensionOrNull
 import org.jetbrains.kotlin.metadata.jvm.JvmProtoBuf
 import org.jetbrains.kotlin.metadata.jvm.deserialization.JvmProtoBufUtil
 
-@Suppress("DEPRECATION_ERROR")
 internal class JvmMetadataExtensions : MetadataExtensions {
-    override fun readClassExtensions(v: KmClassVisitor, proto: ProtoBuf.Class, c: ReadContext) {
+    override fun readClassExtensions(kmClass: KmClass, proto: ProtoBuf.Class, c: ReadContext) {
-        val ext = v.visitExtensions(JvmClassExtensionVisitor.TYPE) as? JvmClassExtensionVisitor ?: return
+        val ext = kmClass.jvm
-        ext as JvmClassExtension
 
         val anonymousObjectOriginName = proto.getExtensionOrNull(JvmProtoBuf.anonymousObjectOriginName)
         if (anonymousObjectOriginName != null) {
-            ext.visitAnonymousObjectOriginName(c[anonymousObjectOriginName])
+            ext.anonymousObjectOriginName = c[anonymousObjectOriginName]
         }
 
         for (property in proto.getExtension(JvmProtoBuf.classLocalVariable)) {
             ext.localDelegatedProperties.add(property.toKmProperty(c))
         }
 
-        ext.visitModuleName(proto.getExtensionOrNull(JvmProtoBuf.classModuleName)?.let(c::get) ?: JvmProtoBufUtil.DEFAULT_MODULE_NAME)
+        ext.moduleName = proto.getExtensionOrNull(JvmProtoBuf.classModuleName)?.let(c::get) ?: JvmProtoBufUtil.DEFAULT_MODULE_NAME
 
-        proto.getExtensionOrNull(JvmProtoBuf.jvmClassFlags)?.let(ext::visitJvmFlags)
+        proto.getExtensionOrNull(JvmProtoBuf.jvmClassFlags)?.let {
-
+            ext.jvmFlags = it
-        ext.visitEnd()
+        }
     }
 
-    override fun readPackageExtensions(v: KmPackageVisitor, proto: ProtoBuf.Package, c: ReadContext) {
+    override fun readPackageExtensions(kmPackage: KmPackage, proto: ProtoBuf.Package, c: ReadContext) {
-        val ext = v.visitExtensions(JvmPackageExtensionVisitor.TYPE) as? JvmPackageExtensionVisitor ?: return
+        val ext = kmPackage.jvm
-        ext as JvmPackageExtension
 
         for (property in proto.getExtension(JvmProtoBuf.packageLocalVariable)) {
             ext.localDelegatedProperties.add(property.toKmProperty(c))
         }
 
-        ext.visitModuleName(proto.getExtensionOrNull(JvmProtoBuf.packageModuleName)?.let(c::get) ?: JvmProtoBufUtil.DEFAULT_MODULE_NAME)
+        ext.moduleName = proto.getExtensionOrNull(JvmProtoBuf.packageModuleName)?.let(c::get) ?: JvmProtoBufUtil.DEFAULT_MODULE_NAME
-
-        ext.visitEnd()
     }
 
     // ModuleFragment is not used by JVM backend.
-    override fun readModuleFragmentExtensions(v: KmModuleFragmentVisitor, proto: ProtoBuf.PackageFragment, c: ReadContext) {}
+    override fun readModuleFragmentExtensions(kmModuleFragment: KmModuleFragment, proto: ProtoBuf.PackageFragment, c: ReadContext) {}
 
-    override fun readFunctionExtensions(v: KmFunctionVisitor, proto: ProtoBuf.Function, c: ReadContext) {
+    override fun readFunctionExtensions(kmFunction: KmFunction, proto: ProtoBuf.Function, c: ReadContext) {
-        val ext = v.visitExtensions(JvmFunctionExtensionVisitor.TYPE) as? JvmFunctionExtensionVisitor ?: return
+        val ext = kmFunction.jvm
-        ext.visit(JvmProtoBufUtil.getJvmMethodSignature(proto, c.strings, c.types)?.wrapAsPublic())
+        ext.signature = JvmProtoBufUtil.getJvmMethodSignature(proto, c.strings, c.types)?.wrapAsPublic()
 
         val lambdaClassOriginName = proto.getExtensionOrNull(JvmProtoBuf.lambdaClassOriginName)
         if (lambdaClassOriginName != null) {
-            ext.visitLambdaClassOriginName(c[lambdaClassOriginName])
+            ext.lambdaClassOriginName = c[lambdaClassOriginName]
         }
-
-        ext.visitEnd()
     }
 
-    override fun readPropertyExtensions(v: KmPropertyVisitor, proto: ProtoBuf.Property, c: ReadContext) {
+    override fun readPropertyExtensions(kmProperty: KmProperty, proto: ProtoBuf.Property, c: ReadContext) {
-        val ext = v.visitExtensions(JvmPropertyExtensionVisitor.TYPE) as? JvmPropertyExtensionVisitor ?: return
+        val ext = kmProperty.jvm
         val fieldSignature = JvmProtoBufUtil.getJvmFieldSignature(proto, c.strings, c.types)
         val propertySignature = proto.getExtensionOrNull(JvmProtoBuf.propertySignature)
         val getterSignature =
             if (propertySignature != null && propertySignature.hasGetter()) propertySignature.getter else null
         val setterSignature =
             if (propertySignature != null && propertySignature.hasSetter()) propertySignature.setter else null
-        ext.visit(
+        ext.jvmFlags = proto.getExtension(JvmProtoBuf.flags)
-            proto.getExtension(JvmProtoBuf.flags),
+        ext.fieldSignature = fieldSignature?.wrapAsPublic()
-            fieldSignature?.wrapAsPublic(),
+        ext.getterSignature = getterSignature?.run { JvmMethodSignature(c[name], c[desc]) }
-            getterSignature?.run { JvmMethodSignature(c[name], c[desc]) },
+        ext.setterSignature = setterSignature?.run { JvmMethodSignature(c[name], c[desc]) }
-            setterSignature?.run { JvmMethodSignature(c[name], c[desc]) }
-        )
 
         val syntheticMethod =
             if (propertySignature != null && propertySignature.hasSyntheticMethod()) propertySignature.syntheticMethod else null
-        ext.visitSyntheticMethodForAnnotations(syntheticMethod?.run { JvmMethodSignature(c[name], c[desc]) })
+        ext.syntheticMethodForAnnotations = syntheticMethod?.run { JvmMethodSignature(c[name], c[desc]) }
 
         val delegateMethod =
             if (propertySignature != null && propertySignature.hasDelegateMethod()) propertySignature.delegateMethod else null
-        ext.visitSyntheticMethodForDelegate(delegateMethod?.run { JvmMethodSignature(c[name], c[desc]) })
+        ext.syntheticMethodForDelegate = delegateMethod?.run { JvmMethodSignature(c[name], c[desc]) }
-
-        ext.visitEnd()
     }
 
-    override fun readConstructorExtensions(v: KmConstructorVisitor, proto: ProtoBuf.Constructor, c: ReadContext) {
+    override fun readConstructorExtensions(kmConstructor: KmConstructor, proto: ProtoBuf.Constructor, c: ReadContext) {
-        val ext = v.visitExtensions(JvmConstructorExtensionVisitor.TYPE) as? JvmConstructorExtensionVisitor ?: return
+        val ext = kmConstructor.jvm
-        ext.visit(JvmProtoBufUtil.getJvmConstructorSignature(proto, c.strings, c.types)?.wrapAsPublic())
+        ext.signature = JvmProtoBufUtil.getJvmConstructorSignature(proto, c.strings, c.types)?.wrapAsPublic()
     }
 
-    override fun readTypeParameterExtensions(v: KmTypeParameterVisitor, proto: ProtoBuf.TypeParameter, c: ReadContext) {
+    override fun readTypeParameterExtensions(kmTypeParameter: KmTypeParameter, proto: ProtoBuf.TypeParameter, c: ReadContext) {
-        val ext = v.visitExtensions(JvmTypeParameterExtensionVisitor.TYPE) as? JvmTypeParameterExtensionVisitor ?: return
+        val ext = kmTypeParameter.jvm
         for (annotation in proto.getExtension(JvmProtoBuf.typeParameterAnnotation)) {
-            ext.visitAnnotation(annotation.readAnnotation(c.strings))
+            ext.annotations.add(annotation.readAnnotation(c.strings))
         }
-        ext.visitEnd()
     }
 
-    override fun readTypeExtensions(v: KmTypeVisitor, proto: ProtoBuf.Type, c: ReadContext) {
+    override fun readTypeExtensions(kmType: KmType, proto: ProtoBuf.Type, c: ReadContext) {
-        val ext = v.visitExtensions(JvmTypeExtensionVisitor.TYPE) as? JvmTypeExtensionVisitor ?: return
+        val ext = kmType.jvm
-        ext.visit(proto.getExtension(JvmProtoBuf.isRaw))
+        ext.isRaw = proto.getExtension(JvmProtoBuf.isRaw)
         for (annotation in proto.getExtension(JvmProtoBuf.typeAnnotation)) {
-            ext.visitAnnotation(annotation.readAnnotation(c.strings))
+            ext.annotations.add(annotation.readAnnotation(c.strings))
         }
-        ext.visitEnd()
     }
 
-    override fun readTypeAliasExtensions(v: KmTypeAliasVisitor, proto: ProtoBuf.TypeAlias, c: ReadContext) {}
+    override fun readTypeAliasExtensions(kmTypeAlias: KmTypeAlias, proto: ProtoBuf.TypeAlias, c: ReadContext) {}
 
-    override fun readValueParameterExtensions(v: KmValueParameterVisitor, proto: ProtoBuf.ValueParameter, c: ReadContext) {}
+    override fun readValueParameterExtensions(kmValueParameter: KmValueParameter, proto: ProtoBuf.ValueParameter, c: ReadContext) {}
 
-    override fun writeClassExtensions(extension: KmClassExtension, proto: ProtoBuf.Class.Builder, c: WriteContext): Boolean {
+    override fun writeClassExtensions(kmClass: KmClass, proto: ProtoBuf.Class.Builder, c: WriteContext) =
-        if (extension.type != JvmClassExtensionVisitor.TYPE) return false
+        with(kmClass.jvm) {
-        extension as JvmClassExtension
+            anonymousObjectOriginName?.let {
-        extension.anonymousObjectOriginName?.let { proto.setExtension(JvmProtoBuf.anonymousObjectOriginName, c[it]) }
+                proto.setExtension(JvmProtoBuf.anonymousObjectOriginName, c[it])
-        extension.localDelegatedProperties.forEach {
+            }
-            proto.addExtension(JvmProtoBuf.classLocalVariable, c.writeProperty(it).build())
+            localDelegatedProperties.forEach {
+                proto.addExtension(JvmProtoBuf.classLocalVariable, c.writeProperty(it).build())
+            }
+            moduleName?.let { moduleName ->
+                if (moduleName != JvmProtoBufUtil.DEFAULT_MODULE_NAME) proto.setExtension(JvmProtoBuf.classModuleName, c[moduleName])
+            }
+            if (jvmFlags != 0) proto.setExtension(JvmProtoBuf.jvmClassFlags, jvmFlags)
         }
-        extension.moduleName?.let { moduleName ->
-            if (moduleName != JvmProtoBufUtil.DEFAULT_MODULE_NAME) proto.setExtension(JvmProtoBuf.classModuleName, c[moduleName])
-        }
-        if (extension.jvmFlags != 0) proto.setExtension(JvmProtoBuf.jvmClassFlags, extension.jvmFlags)
-        return true
-    }
 
     override fun writePackageExtensions(
-        extension: KmPackageExtension, proto: ProtoBuf.Package.Builder, c: WriteContext
+        kmPackage: KmPackage, proto: ProtoBuf.Package.Builder, c: WriteContext,
-    ): Boolean {
+    ): Unit = with(kmPackage.jvm) {
-        if (extension.type != JvmPackageExtensionVisitor.TYPE) return false
+        localDelegatedProperties.forEach {
-        extension as JvmPackageExtension
-        extension.localDelegatedProperties.forEach {
             proto.addExtension(JvmProtoBuf.packageLocalVariable, c.writeProperty(it).build())
         }
-        extension.moduleName?.let { name ->
+        moduleName?.let { name ->
             if (name != JvmProtoBufUtil.DEFAULT_MODULE_NAME) {
                 proto.setExtension(JvmProtoBuf.packageModuleName, c[name])
             }
         }
-        return true
     }
 
     // PackageFragment is not used by JVM backend.
     override fun writeModuleFragmentExtensions(
-        type: KmExtensionType,
+        kmModuleFragment: KmModuleFragment,
         proto: ProtoBuf.PackageFragment.Builder,
-        c: WriteContext
+        c: WriteContext,
-    ): KmModuleFragmentExtensionVisitor? = null
+    ) = Unit
 
     override fun writeFunctionExtensions(
-        type: KmExtensionType, proto: ProtoBuf.Function.Builder, c: WriteContext
+        kmFunction: KmFunction, proto: ProtoBuf.Function.Builder, c: WriteContext,
-    ): KmFunctionExtensionVisitor? {
+    ) {
-        if (type != JvmFunctionExtensionVisitor.TYPE) return null
+        with(kmFunction.jvm) {
-        return object : JvmFunctionExtensionVisitor() {
+            signature?.let { proto.setExtension(JvmProtoBuf.methodSignature, it.toJvmMethodSignature(c)) }
-            override fun visit(signature: JvmMethodSignature?) {
+            lambdaClassOriginName?.let { proto.setExtension(JvmProtoBuf.lambdaClassOriginName, c[it]) }
-                if (signature != null) {
-                    proto.setExtension(JvmProtoBuf.methodSignature, signature.toJvmMethodSignature(c))
-                }
-            }
-
-            override fun visitLambdaClassOriginName(internalName: String) {
-                proto.setExtension(JvmProtoBuf.lambdaClassOriginName, c[internalName])
-            }
         }
     }
 
     override fun writePropertyExtensions(
-        type: KmExtensionType, proto: ProtoBuf.Property.Builder, c: WriteContext
+        kmProperty: KmProperty, proto: ProtoBuf.Property.Builder, c: WriteContext,
-    ): KmPropertyExtensionVisitor? {
+    ) = with(kmProperty.jvm) {
-        if (type != JvmPropertyExtensionVisitor.TYPE) return null
+        val composedSignature: JvmProtoBuf.JvmPropertySignature.Builder = JvmProtoBuf.JvmPropertySignature.newBuilder()
-        return object : JvmPropertyExtensionVisitor() {
+        var hasSignature = false
-            private var jvmFlags: Int = ProtoBuf.Property.getDefaultInstance().getExtension(JvmProtoBuf.flags)
-            private var signatureOrNull: JvmProtoBuf.JvmPropertySignature.Builder? = null
 
-            private val signature: JvmProtoBuf.JvmPropertySignature.Builder
+        if (fieldSignature != null) {
-                get() = signatureOrNull ?: JvmProtoBuf.JvmPropertySignature.newBuilder().also { signatureOrNull = it }
+            hasSignature = true
-
+            composedSignature.field = JvmProtoBuf.JvmFieldSignature.newBuilder().also { field ->
-            override fun visit(
+                field.name = c[fieldSignature!!.name]
-                jvmFlags: Int,
+                field.desc = c[fieldSignature!!.descriptor]
-                fieldSignature: JvmFieldSignature?,
+            }.build()
-                getterSignature: JvmMethodSignature?,
+        }
-                setterSignature: JvmMethodSignature?
+        if (getterSignature != null) {
-            ) {
+            hasSignature = true
-                this.jvmFlags = jvmFlags
+            composedSignature.getter = getterSignature!!.toJvmMethodSignature(c)
-                if (fieldSignature != null) {
+        }
-                    signature.field = JvmProtoBuf.JvmFieldSignature.newBuilder().also { field ->
+        if (setterSignature != null) {
-                        field.name = c[fieldSignature.name]
+            hasSignature = true
-                        field.desc = c[fieldSignature.descriptor]
+            composedSignature.setter = setterSignature!!.toJvmMethodSignature(c)
-                    }.build()
+        }
-                }
+        if (hasSignature && syntheticMethodForAnnotations != null) {
-                if (getterSignature != null) {
+            composedSignature.syntheticMethod = syntheticMethodForAnnotations!!.toJvmMethodSignature(c)
-                    signature.getter = getterSignature.toJvmMethodSignature(c)
+        }
-                }
+        if (hasSignature && syntheticMethodForDelegate != null) {
-                if (setterSignature != null) {
+            composedSignature.delegateMethod = syntheticMethodForDelegate!!.toJvmMethodSignature(c)
-                    signature.setter = setterSignature.toJvmMethodSignature(c)
+        }
-                }
+        if (jvmFlags != ProtoBuf.Property.getDefaultInstance().getExtension(JvmProtoBuf.flags)) {
-            }
+            proto.setExtension(JvmProtoBuf.flags, jvmFlags)
-
+        }
-            override fun visitSyntheticMethodForAnnotations(signature: JvmMethodSignature?) {
+        if (hasSignature) {
-                if (signature == null) return
+            proto.setExtension(JvmProtoBuf.propertySignature, composedSignature.build())
-
-                this.signature.syntheticMethod = signature.toJvmMethodSignature(c)
-            }
-
-            override fun visitSyntheticMethodForDelegate(signature: JvmMethodSignature?) {
-                if (signature == null) return
-
-                this.signature.delegateMethod = signature.toJvmMethodSignature(c)
-            }
-
-            override fun visitEnd() {
-                if (jvmFlags != ProtoBuf.Property.getDefaultInstance().getExtension(JvmProtoBuf.flags)) {
-                    proto.setExtension(JvmProtoBuf.flags, jvmFlags)
-                }
-                if (signatureOrNull != null) {
-                    proto.setExtension(JvmProtoBuf.propertySignature, signature.build())
-                }
-            }
         }
     }
 
     override fun writeConstructorExtensions(
-        type: KmExtensionType, proto: ProtoBuf.Constructor.Builder, c: WriteContext
+        kmConstructor: KmConstructor, proto: ProtoBuf.Constructor.Builder, c: WriteContext,
-    ): KmConstructorExtensionVisitor? {
+    ): Unit = with(kmConstructor.jvm) {
-        if (type != JvmConstructorExtensionVisitor.TYPE) return null
+        signature?.let { proto.setExtension(JvmProtoBuf.constructorSignature, it.toJvmMethodSignature(c)) }
-        return object : JvmConstructorExtensionVisitor() {
-            override fun visit(signature: JvmMethodSignature?) {
-                if (signature != null) {
-                    proto.setExtension(JvmProtoBuf.constructorSignature, signature.toJvmMethodSignature(c))
-                }
-            }
-        }
     }
 
     override fun writeTypeParameterExtensions(
-        type: KmExtensionType, proto: ProtoBuf.TypeParameter.Builder, c: WriteContext
+        kmTypeParameter: KmTypeParameter, proto: ProtoBuf.TypeParameter.Builder, c: WriteContext,
-    ): KmTypeParameterExtensionVisitor? {
+    ) = with(kmTypeParameter.jvm) {
-        if (type != JvmTypeParameterExtensionVisitor.TYPE) return null
+        annotations.forEach { annotation ->
-        return object : JvmTypeParameterExtensionVisitor() {
+            proto.addExtension(JvmProtoBuf.typeParameterAnnotation, annotation.writeAnnotation(c.strings).build())
-            override fun visitAnnotation(annotation: KmAnnotation) {
-                proto.addExtension(JvmProtoBuf.typeParameterAnnotation, annotation.writeAnnotation(c.strings).build())
-            }
         }
     }
 
-    override fun writeTypeExtensions(type: KmExtensionType, proto: ProtoBuf.Type.Builder, c: WriteContext): KmTypeExtensionVisitor? {
+    override fun writeTypeExtensions(type: KmType, proto: ProtoBuf.Type.Builder, c: WriteContext) =
-        if (type != JvmTypeExtensionVisitor.TYPE) return null
+        with(type.jvm) {
-        return object : JvmTypeExtensionVisitor() {
+            if (isRaw) proto.setExtension(JvmProtoBuf.isRaw, true)
-            override fun visit(isRaw: Boolean) {
+            annotations.forEach { annotation ->
-                if (isRaw) {
-                    proto.setExtension(JvmProtoBuf.isRaw, true)
-                }
-            }
-
-            override fun visitAnnotation(annotation: KmAnnotation) {
                 proto.addExtension(JvmProtoBuf.typeAnnotation, annotation.writeAnnotation(c.strings).build())
             }
         }
-    }
 
     override fun writeTypeAliasExtensions(
-        type: KmExtensionType,
+        typeAlias: KmTypeAlias,
         proto: ProtoBuf.TypeAlias.Builder,
-        c: WriteContext
+        c: WriteContext,
-    ): KmTypeAliasExtensionVisitor? = null
+    ) = Unit
 
     override fun writeValueParameterExtensions(
-        type: KmExtensionType,
+        valueParameter: KmValueParameter,
         proto: ProtoBuf.ValueParameter.Builder,
-        c: WriteContext
+        c: WriteContext,
-    ): KmValueParameterExtensionVisitor? = null
+    ) = Unit
 
     override fun createClassExtension(): KmClassExtension = JvmClassExtension()
 
     override fun createPackageExtension(): KmPackageExtension = JvmPackageExtension()
 
+    @Suppress("DEPRECATION_ERROR")
     override fun createModuleFragmentExtensions(): KmModuleFragmentExtension =
         object : KmModuleFragmentExtension {
             override val type: KmExtensionType = KmExtensionType(KmModuleFragmentExtension::class)

libraries/kotlinx-metadata/klib/src/kotlinx/metadata/klib/KlibModuleMetadata.kt

@@ -2,7 +2,6 @@
  * Copyright 2010-2019 JetBrains s.r.o. and Kotlin Programming Language contributors.
  * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
  */
-@file:Suppress("DEPRECATION_ERROR")
 
 package kotlinx.metadata.klib
 

libraries/kotlinx-metadata/klib/src/kotlinx/metadata/klib/impl/klibExtensionNodes.kt

@@ -2,7 +2,7 @@
  * Copyright 2010-2019 JetBrains s.r.o. and Kotlin Programming Language contributors.
  * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
  */
-@file:Suppress("DEPRECATION_ERROR")
+@file:Suppress("DEPRECATION_ERROR") // Extension visitors
 
 package kotlinx.metadata.klib.impl
 

libraries/kotlinx-metadata/klib/src/kotlinx/metadata/klib/impl/klibMetadataExtensions.kt

@@ -18,7 +18,7 @@ import org.jetbrains.kotlin.name.ClassId
 import org.jetbrains.kotlin.name.FqName
 import org.jetbrains.kotlin.serialization.StringTableImpl
 
-@Suppress("DEPRECATION", "DEPRECATION_ERROR")
+@Suppress("DEPRECATION_ERROR")
 internal class KlibMetadataExtensions : MetadataExtensions {
 
     private fun ReadContext.getSourceFile(index: Int) =
@@ -27,8 +27,8 @@ internal class KlibMetadataExtensions : MetadataExtensions {
     private fun WriteContext.getIndexOf(file: KlibSourceFile) =
         strings.getStringIndex(file.name)
 
-    override fun readClassExtensions(v: KmClassVisitor, proto: ProtoBuf.Class, c: ReadContext) {
+    override fun readClassExtensions(kmClass: KmClass, proto: ProtoBuf.Class, c: ReadContext) {
-        val extension = v.visitExtensions(KlibClassExtensionVisitor.TYPE) as? KlibClassExtensionVisitor ?: return
+        val extension = kmClass.visitExtensions(KlibClassExtensionVisitor.TYPE) as? KlibClassExtensionVisitor ?: return
 
         proto.getExtension(KlibMetadataProtoBuf.classAnnotation).forEach { annotation ->
             extension.visitAnnotation(annotation.readAnnotation(c.strings))
@@ -48,8 +48,8 @@ internal class KlibMetadataExtensions : MetadataExtensions {
         }
     }
 
-    override fun readPackageExtensions(v: KmPackageVisitor, proto: ProtoBuf.Package, c: ReadContext) {
+    override fun readPackageExtensions(kmPackage: KmPackage, proto: ProtoBuf.Package, c: ReadContext) {
-        val extension = v.visitExtensions(KlibPackageExtensionVisitor.TYPE) as? KlibPackageExtensionVisitor ?: return
+        val extension = kmPackage.visitExtensions(KlibPackageExtensionVisitor.TYPE) as? KlibPackageExtensionVisitor ?: return
 
         proto.getExtensionOrNull(KlibMetadataProtoBuf.packageFqName)?.let {
             val fqName = (c.strings as NameResolverImpl).getPackageFqName(it)
@@ -57,8 +57,8 @@ internal class KlibMetadataExtensions : MetadataExtensions {
         }
     }
 
-    override fun readModuleFragmentExtensions(v: KmModuleFragmentVisitor, proto: ProtoBuf.PackageFragment, c: ReadContext) {
+    override fun readModuleFragmentExtensions(kmModuleFragment: KmModuleFragment, proto: ProtoBuf.PackageFragment, c: ReadContext) {
-        val extension = v.visitExtensions(KlibModuleFragmentExtensionVisitor.TYPE) as? KlibModuleFragmentExtensionVisitor ?: return
+        val extension = kmModuleFragment.visitExtensions(KlibModuleFragmentExtensionVisitor.TYPE) as? KlibModuleFragmentExtensionVisitor ?: return
 
         proto.getExtension(KlibMetadataProtoBuf.packageFragmentFiles)
             .map { c.getSourceFile(it) }
@@ -69,8 +69,8 @@ internal class KlibMetadataExtensions : MetadataExtensions {
             .forEach(extension::visitClassName)
     }
 
-    override fun readFunctionExtensions(v: KmFunctionVisitor, proto: ProtoBuf.Function, c: ReadContext) {
+    override fun readFunctionExtensions(kmFunction: KmFunction, proto: ProtoBuf.Function, c: ReadContext) {
-        val extension = v.visitExtensions(KlibFunctionExtensionVisitor.TYPE) as? KlibFunctionExtensionVisitor ?: return
+        val extension = kmFunction.visitExtensions(KlibFunctionExtensionVisitor.TYPE) as? KlibFunctionExtensionVisitor ?: return
 
         proto.getExtension(KlibMetadataProtoBuf.functionAnnotation).forEach { annotation ->
             extension.visitAnnotation(annotation.readAnnotation(c.strings))
@@ -84,8 +84,8 @@ internal class KlibMetadataExtensions : MetadataExtensions {
         }
     }
 
-    override fun readPropertyExtensions(v: KmPropertyVisitor, proto: ProtoBuf.Property, c: ReadContext) {
+    override fun readPropertyExtensions(kmProperty: KmProperty, proto: ProtoBuf.Property, c: ReadContext) {
-        val extension = v.visitExtensions(KlibPropertyExtensionVisitor.TYPE) as? KlibPropertyExtensionVisitor ?: return
+        val extension = kmProperty.visitExtensions(KlibPropertyExtensionVisitor.TYPE) as? KlibPropertyExtensionVisitor ?: return
 
         proto.getExtension(KlibMetadataProtoBuf.propertyAnnotation).forEach { annotation ->
             extension.visitAnnotation(annotation.readAnnotation(c.strings))
@@ -105,8 +105,8 @@ internal class KlibMetadataExtensions : MetadataExtensions {
         }
     }
 
-    override fun readConstructorExtensions(v: KmConstructorVisitor, proto: ProtoBuf.Constructor, c: ReadContext) {
+    override fun readConstructorExtensions(kmConstructor: KmConstructor, proto: ProtoBuf.Constructor, c: ReadContext) {
-        val extension = v.visitExtensions(KlibConstructorExtensionVisitor.TYPE) as? KlibConstructorExtensionVisitor ?: return
+        val extension = kmConstructor.visitExtensions(KlibConstructorExtensionVisitor.TYPE) as? KlibConstructorExtensionVisitor ?: return
 
         proto.getExtension(KlibMetadataProtoBuf.constructorAnnotation).forEach { annotation ->
             extension.visitAnnotation(annotation.readAnnotation(c.strings))
@@ -116,8 +116,8 @@ internal class KlibMetadataExtensions : MetadataExtensions {
         }
     }
 
-    override fun readTypeParameterExtensions(v: KmTypeParameterVisitor, proto: ProtoBuf.TypeParameter, c: ReadContext) {
+    override fun readTypeParameterExtensions(kmTypeParameter: KmTypeParameter, proto: ProtoBuf.TypeParameter, c: ReadContext) {
-        val extension = v.visitExtensions(KlibTypeParameterExtensionVisitor.TYPE) as? KlibTypeParameterExtensionVisitor ?: return
+        val extension = kmTypeParameter.visitExtensions(KlibTypeParameterExtensionVisitor.TYPE) as? KlibTypeParameterExtensionVisitor ?: return
 
         proto.getExtension(KlibMetadataProtoBuf.typeParameterAnnotation).forEach { annotation ->
             extension.visitAnnotation(annotation.readAnnotation(c.strings))
@@ -127,33 +127,32 @@ internal class KlibMetadataExtensions : MetadataExtensions {
         }
     }
 
-    override fun readTypeExtensions(v: KmTypeVisitor, proto: ProtoBuf.Type, c: ReadContext) {
+    override fun readTypeExtensions(kmType: KmType, proto: ProtoBuf.Type, c: ReadContext) {
-        val extension = v.visitExtensions(KlibTypeExtensionVisitor.TYPE) as? KlibTypeExtensionVisitor ?: return
+        val extension = kmType.visitExtensions(KlibTypeExtensionVisitor.TYPE) as? KlibTypeExtensionVisitor ?: return
 
         proto.getExtension(KlibMetadataProtoBuf.typeAnnotation).forEach { annotation ->
             extension.visitAnnotation(annotation.readAnnotation(c.strings))
         }
     }
 
-    override fun readTypeAliasExtensions(v: KmTypeAliasVisitor, proto: ProtoBuf.TypeAlias, c: ReadContext) {
+    override fun readTypeAliasExtensions(kmTypeAlias: KmTypeAlias, proto: ProtoBuf.TypeAlias, c: ReadContext) {
-        val extension = v.visitExtensions(KlibTypeAliasExtensionVisitor.TYPE) as? KlibTypeAliasExtensionVisitor ?: return
+        val extension = kmTypeAlias.visitExtensions(KlibTypeAliasExtensionVisitor.TYPE) as? KlibTypeAliasExtensionVisitor ?: return
 
         proto.getExtension(KlibMetadataProtoBuf.typeAliasUniqId).let { descriptorUniqId ->
             extension.visitUniqId(descriptorUniqId.readUniqId())
         }
     }
 
-    override fun readValueParameterExtensions(v: KmValueParameterVisitor, proto: ProtoBuf.ValueParameter, c: ReadContext) {
+    override fun readValueParameterExtensions(kmValueParameter: KmValueParameter, proto: ProtoBuf.ValueParameter, c: ReadContext) {
-        val extension = v.visitExtensions(KlibValueParameterExtensionVisitor.TYPE) as? KlibValueParameterExtensionVisitor ?: return
+        val extension = kmValueParameter.visitExtensions(KlibValueParameterExtensionVisitor.TYPE) as? KlibValueParameterExtensionVisitor ?: return
 
         proto.getExtension(KlibMetadataProtoBuf.parameterAnnotation).forEach { annotation ->
             extension.visitAnnotation(annotation.readAnnotation(c.strings))
         }
     }
 
-    override fun writeClassExtensions(extension: KmClassExtension, proto: ProtoBuf.Class.Builder, c: WriteContext): Boolean {
+    override fun writeClassExtensions(kmClass: KmClass, proto: ProtoBuf.Class.Builder, c: WriteContext) {
-        if (extension.type != KlibClassExtensionVisitor.TYPE) return false
+        kmClass.klibExtensions.accept(object : KlibClassExtensionVisitor() {
-        extension.accept(object : KlibClassExtensionVisitor() {
             override fun visitAnnotation(annotation: KmAnnotation) {
                 proto.addExtension(
                     KlibMetadataProtoBuf.classAnnotation,
@@ -192,31 +191,27 @@ internal class KlibMetadataExtensions : MetadataExtensions {
                 }
             }
         })
-        return true
     }
 
     override fun writePackageExtensions(
-        extension: KmPackageExtension,
+        kmPackage: KmPackage,
         proto: ProtoBuf.Package.Builder,
         c: WriteContext
-    ): Boolean {
+    ) {
-        if (extension.type != KlibPackageExtensionVisitor.TYPE) return false
+        kmPackage.klibExtensions.accept(object : KlibPackageExtensionVisitor() {
-        extension.accept(object : KlibPackageExtensionVisitor() {
             override fun visitFqName(name: String) {
                 val nameIdx = (c.strings as StringTableImpl).getPackageFqNameIndex(FqName(name))
                 proto.setExtension(KlibMetadataProtoBuf.packageFqName, nameIdx)
             }
         })
-        return true
     }
 
     override fun writeModuleFragmentExtensions(
-        type: KmExtensionType,
+        kmModuleFragment: KmModuleFragment,
         proto: ProtoBuf.PackageFragment.Builder,
         c: WriteContext
-    ): KmModuleFragmentExtensionVisitor? {
+    ) {
-        if (type != KlibModuleFragmentExtensionVisitor.TYPE) return null
+        kmModuleFragment.klibExtensions.accept(object : KlibModuleFragmentExtensionVisitor() {
-        return object : KlibModuleFragmentExtensionVisitor() {
             override fun visitFile(file: KlibSourceFile) {
                 val fileIdx = c.getIndexOf(file)
                 proto.addExtension(KlibMetadataProtoBuf.packageFragmentFiles, fileIdx)
@@ -230,16 +225,15 @@ internal class KlibMetadataExtensions : MetadataExtensions {
                 val classNameIdx = (c.strings as StringTableImpl).getQualifiedClassNameIndex(ClassId.fromString(className))
                 proto.addExtension(KlibMetadataProtoBuf.className, classNameIdx)
             }
-        }
+        })
     }
 
     override fun writeFunctionExtensions(
-        type: KmExtensionType,
+        kmFunction: KmFunction,
         proto: ProtoBuf.Function.Builder,
         c: WriteContext
-    ): KmFunctionExtensionVisitor? {
+    ) {
-        if (type != KlibFunctionExtensionVisitor.TYPE) return null
+        kmFunction.klibExtensions.accept(object : KlibFunctionExtensionVisitor() {
-        return object : KlibFunctionExtensionVisitor() {
             override fun visitAnnotation(annotation: KmAnnotation) {
                 proto.addExtension(
                     KlibMetadataProtoBuf.functionAnnotation,
@@ -258,16 +252,15 @@ internal class KlibMetadataExtensions : MetadataExtensions {
                 val index = c.getIndexOf(file)
                 proto.setExtension(KlibMetadataProtoBuf.functionFile, index)
             }
-        }
+        })
     }
 
     override fun writePropertyExtensions(
-        type: KmExtensionType,
+        kmProperty: KmProperty,
         proto: ProtoBuf.Property.Builder,
         c: WriteContext
-    ): KmPropertyExtensionVisitor? {
+    ) {
-        if (type != KlibPropertyExtensionVisitor.TYPE) return null
+        kmProperty.klibExtensions.accept(object : KlibPropertyExtensionVisitor() {
-        return object : KlibPropertyExtensionVisitor() {
             override fun visitAnnotation(annotation: KmAnnotation) {
                 proto.addExtension(
                     KlibMetadataProtoBuf.propertyAnnotation,
@@ -309,16 +302,15 @@ internal class KlibMetadataExtensions : MetadataExtensions {
                     value.writeAnnotationArgument(c.strings).build()
                 )
             }
-        }
+        })
     }
 
     override fun writeConstructorExtensions(
-        type: KmExtensionType,
+        kmConstructor: KmConstructor,
         proto: ProtoBuf.Constructor.Builder,
         c: WriteContext
-    ): KmConstructorExtensionVisitor? {
+    ) {
-        if (type != KlibConstructorExtensionVisitor.TYPE) return null
+        kmConstructor.klibExtensions.accept(object : KlibConstructorExtensionVisitor() {
-        return object : KlibConstructorExtensionVisitor() {
             override fun visitAnnotation(annotation: KmAnnotation) {
                 proto.addExtension(
                     KlibMetadataProtoBuf.constructorAnnotation,
@@ -332,16 +324,15 @@ internal class KlibMetadataExtensions : MetadataExtensions {
                     uniqId.writeUniqId().build()
                 )
             }
-        }
+        })
     }
 
     override fun writeTypeParameterExtensions(
-        type: KmExtensionType,
+        kmTypeParameter: KmTypeParameter,
         proto: ProtoBuf.TypeParameter.Builder,
         c: WriteContext
-    ): KmTypeParameterExtensionVisitor? {
+    ) {
-        if (type != KlibTypeParameterExtensionVisitor.TYPE) return null
+        kmTypeParameter.klibExtensions.accept(object : KlibTypeParameterExtensionVisitor() {
-        return object : KlibTypeParameterExtensionVisitor() {
             override fun visitAnnotation(annotation: KmAnnotation) {
                 proto.addExtension(
                     KlibMetadataProtoBuf.typeParameterAnnotation,
@@ -355,51 +346,48 @@ internal class KlibMetadataExtensions : MetadataExtensions {
                     uniqId.writeUniqId().build()
                 )
             }
-        }
+        })
     }
 
-    override fun writeTypeExtensions(type: KmExtensionType, proto: ProtoBuf.Type.Builder, c: WriteContext): KmTypeExtensionVisitor? {
+    override fun writeTypeExtensions(type: KmType, proto: ProtoBuf.Type.Builder, c: WriteContext) {
-        if (type != KlibTypeExtensionVisitor.TYPE) return null
+        type.klibExtensions.accept(object : KlibTypeExtensionVisitor() {
-        return object : KlibTypeExtensionVisitor() {
             override fun visitAnnotation(annotation: KmAnnotation) {
                 proto.addExtension(
                     KlibMetadataProtoBuf.typeAnnotation,
                     annotation.writeAnnotation(c.strings).build()
                 )
             }
-        }
+        })
     }
 
     override fun writeTypeAliasExtensions(
-        type: KmExtensionType,
+        typeAlias: KmTypeAlias,
         proto: ProtoBuf.TypeAlias.Builder,
         c: WriteContext
-    ): KmTypeAliasExtensionVisitor? {
+    ) {
-        if (type != KlibTypeAliasExtensionVisitor.TYPE) return null
+        typeAlias.klibExtensions.accept(object : KlibTypeAliasExtensionVisitor() {
-        return object : KlibTypeAliasExtensionVisitor() {
             override fun visitUniqId(uniqId: UniqId) {
                 proto.setExtension(
                     KlibMetadataProtoBuf.typeAliasUniqId,
                     uniqId.writeUniqId().build()
                 )
             }
-        }
+        })
     }
 
     override fun writeValueParameterExtensions(
-        type: KmExtensionType,
+        valueParameter: KmValueParameter,
         proto: ProtoBuf.ValueParameter.Builder,
         c: WriteContext
-    ): KmValueParameterExtensionVisitor? {
+    ) {
-        if (type != KlibValueParameterExtensionVisitor.TYPE) return null
+        valueParameter.klibExtensions.accept(object : KlibValueParameterExtensionVisitor() {
-        return object : KlibValueParameterExtensionVisitor() {
             override fun visitAnnotation(annotation: KmAnnotation) {
                 proto.addExtension(
                     KlibMetadataProtoBuf.parameterAnnotation,
                     annotation.writeAnnotation(c.strings).build()
                 )
             }
-        }
+        })
     }
 
     override fun createClassExtension(): KmClassExtension =

libraries/kotlinx-metadata/klib/src/kotlinx/metadata/klib/klibMetadataExtensionVisitors.kt

@@ -2,7 +2,7 @@
  * Copyright 2010-2019 JetBrains s.r.o. and Kotlin Programming Language contributors.
  * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
  */
-@file:Suppress("DEPRECATION_ERROR")
+@file:Suppress("DEPRECATION_ERROR")  // Extension visitors
 
 package kotlinx.metadata.klib
 

libraries/kotlinx-metadata/src/kotlinx/metadata/Nodes.kt

@@ -821,7 +821,7 @@ public class KmTypeParameter @Deprecated(flagsCtorDeprecated) constructor(
         KmType(flags).addTo(upperBounds)
 
     @Deprecated(VISITOR_API_MESSAGE, level = DeprecationLevel.ERROR)
-    override fun visitExtensions(type: KmExtensionType): KmTypeParameterExtensionVisitor? =
+    override fun visitExtensions(type: KmExtensionType): KmTypeParameterExtensionVisitor =
         extensions.singleOfType(type)
 
     /**

libraries/kotlinx-metadata/src/kotlinx/metadata/internal/Readers.kt

@@ -86,9 +86,7 @@ public fun ProtoBuf.Class.toKmClass(
     contextReceiverTypes(c.types).mapTo(v.contextReceiverTypes) { it.toKmType(c) }
     versionRequirementList.mapTo(v.versionRequirements) { readVersionRequirement(it, c) }
 
-    for (extension in c.extensions) {
+    c.extensions.forEach { it.readClassExtensions(v, this, c) }
-        extension.readClassExtensions(v, this, c)
-    }
 
     return v
 }
@@ -119,9 +117,7 @@ public fun ProtoBuf.Package.toKmPackage(
 
     v.visitDeclarations(functionList, propertyList, typeAliasList, c)
 
-    for (extension in c.extensions) {
+    c.extensions.forEach { it.readPackageExtensions(v, this, c) }
-        extension.readPackageExtensions(v, this, c)
-    }
 
     return v
 }
@@ -141,9 +137,7 @@ public fun ProtoBuf.PackageFragment.toKmModuleFragment(
     v.pkg = `package`.toKmPackage(strings, contextExtensions)
     class_List.mapTo(v.classes) { it.toKmClass(strings, contextExtensions) }
 
-    for (extension in c.extensions) {
+    c.extensions.forEach { it.readModuleFragmentExtensions(v, this, c) }
-        extension.readModuleFragmentExtensions(v, this, c)
-    }
 
     return v
 }
@@ -171,9 +165,7 @@ private fun ProtoBuf.Constructor.toKmConstructor(c: ReadContext): KmConstructor
     valueParameterList.mapTo(v.valueParameters) { it.toKmValueParameter(c) }
     versionRequirementList.mapTo(v.versionRequirements) { readVersionRequirement(it, c) }
 
-    for (extension in c.extensions) {
+    c.extensions.forEach { it.readConstructorExtensions(v, this, c) }
-        extension.readConstructorExtensions(v, this, c)
-    }
 
     return v
 }
@@ -196,9 +188,7 @@ private fun ProtoBuf.Function.toKmFunction(outer: ReadContext): KmFunction {
 
     versionRequirementList.mapTo(v.versionRequirements) { readVersionRequirement(it, c) }
 
-    for (extension in c.extensions) {
+    c.extensions.forEach { it.readFunctionExtensions(v, this, c) }
-        extension.readFunctionExtensions(v, this, c)
-    }
 
     return v
 }
@@ -217,9 +207,7 @@ public fun ProtoBuf.Property.toKmProperty(outer: ReadContext): KmProperty {
     v.returnType = returnType(c.types).toKmType(c)
     versionRequirementList.mapTo(v.versionRequirements) { readVersionRequirement(it, c) }
 
-    for (extension in c.extensions) {
+    c.extensions.forEach { it.readPropertyExtensions(v, this, c) }
-        extension.readPropertyExtensions(v, this, c)
-    }
 
     return v
 }
@@ -236,9 +224,7 @@ private fun ProtoBuf.TypeAlias.toKmTypeAlias(outer: ReadContext): KmTypeAlias {
 
     versionRequirementList.mapTo(v.versionRequirements) { readVersionRequirement(it, c) }
 
-    for (extension in c.extensions) {
+    c.extensions.forEach { it.readTypeAliasExtensions(v, this, c) }
-        extension.readTypeAliasExtensions(v, this, c)
-    }
 
     return v
 }
@@ -249,9 +235,7 @@ private fun ProtoBuf.ValueParameter.toKmValueParameter(c: ReadContext): KmValueP
 
     v.varargElementType = varargElementType(c.types)?.toKmType(c)
 
-    for (extension in c.extensions) {
+    c.extensions.forEach { it.readValueParameterExtensions(v, this, c) }
-        extension.readValueParameterExtensions(v, this, c)
-    }
 
     return v
 }
@@ -268,9 +252,7 @@ private fun ProtoBuf.TypeParameter.toKmTypeParameter(
 
     upperBounds(c.types).mapTo(ktp.upperBounds) { it.toKmType(c) }
 
-    for (extension in c.extensions) {
+    c.extensions.forEach { it.readTypeParameterExtensions(ktp, this, c) }
-        extension.readTypeParameterExtensions(ktp, this, c)
-    }
 
     return ktp
 }
@@ -313,9 +295,7 @@ private fun ProtoBuf.Type.toKmType(c: ReadContext): KmType {
         KmFlexibleTypeUpperBound(it, if (hasFlexibleTypeCapabilitiesId()) c[flexibleTypeCapabilitiesId] else null)
     }
 
-    for (extension in c.extensions) {
+    c.extensions.forEach { it.readTypeExtensions(v, this, c) }
-        extension.readTypeExtensions(v, this, c)
-    }
 
     return v
 }

libraries/kotlinx-metadata/src/kotlinx/metadata/internal/WriteUtils.kt

@@ -6,9 +6,6 @@
 package kotlinx.metadata.internal
 
 import kotlinx.metadata.*
-import kotlinx.metadata.internal.extensions.KmExtension
-import kotlinx.metadata.internal.extensions.MetadataExtensions
-import kotlinx.metadata.internal.extensions.applySingleExtension
 import org.jetbrains.kotlin.metadata.ProtoBuf
 import org.jetbrains.kotlin.metadata.deserialization.Flags
 import org.jetbrains.kotlin.metadata.serialization.StringTable
@@ -115,9 +112,3 @@ internal fun StringTable.getClassNameIndex(name: ClassName): Int =
         getQualifiedClassNameIndex(name.substring(1), true)
     else
         getQualifiedClassNameIndex(name, false)
-
-@Suppress("DEPRECATION_ERROR")
-internal fun <V : KmExtensionVisitor, E : KmExtension<V>> List<E>.writeExtensions(writer: MetadataExtensions.(KmExtensionType) -> V?) =
-    forEach { ext ->
-        applySingleExtension(ext.type) { writer(ext.type) }?.let { ext.accept(it) }
-    }

libraries/kotlinx-metadata/src/kotlinx/metadata/internal/Writers.kt

@@ -8,7 +8,6 @@ package kotlinx.metadata.internal
 import kotlinx.metadata.*
 import kotlinx.metadata.internal.common.KmModuleFragment
 import kotlinx.metadata.internal.extensions.MetadataExtensions
-import kotlinx.metadata.internal.extensions.matchExtensions
 import org.jetbrains.kotlin.metadata.ProtoBuf
 import org.jetbrains.kotlin.metadata.deserialization.VersionRequirement
 import org.jetbrains.kotlin.metadata.serialization.MutableVersionRequirementTable
@@ -24,6 +23,8 @@ public interface WriteContextExtension
 public open class WriteContext(public val strings: StringTable, public val contextExtensions: List<WriteContextExtension> = emptyList()) {
     internal val versionRequirements: MutableVersionRequirementTable = MutableVersionRequirementTable()
 
+    internal val extensions = MetadataExtensions.INSTANCES
+
     public operator fun get(string: String): Int =
         strings.getStringIndex(string)
 
@@ -36,8 +37,8 @@ private fun WriteContext.writeTypeParameter(kmTypeParameter: KmTypeParameter): P
     kmTypeParameter.upperBounds.forEach { ub ->
         t.addUpperBound(writeType(ub).build())
     }
-    kmTypeParameter.extensions.writeExtensions {
+    extensions.forEach {
-        writeTypeParameterExtensions(it, t, this@writeTypeParameter)
+        it.writeTypeParameterExtensions(kmTypeParameter, t, this)
     }
     t.name = this[kmTypeParameter.name]
     t.id = kmTypeParameter.id
@@ -91,9 +92,7 @@ private fun WriteContext.writeType(kmType: KmType): ProtoBuf.Type.Builder {
         t.flexibleUpperBound = fubType.build()
     }
 
-    kmType.extensions.writeExtensions {
+    extensions.forEach { it.writeTypeExtensions(kmType, t, this) }
-        writeTypeExtensions(it, t, this@writeType)
-    }
 
     if (kmType.isNullable) {
         t.nullable = true
@@ -112,8 +111,8 @@ private fun WriteContext.writeConstructor(kmConstructor: KmConstructor): ProtoBu
         t.addValueParameter(writeValueParameter(it).build())
     }
     kmConstructor.versionRequirements.forEach { t.addVersionRequirement(writeVersionRequirement(it)) }
-    kmConstructor.extensions.writeExtensions {
+    extensions.forEach {
-        writeConstructorExtensions(it, t, this@writeConstructor)
+        it.writeConstructorExtensions(kmConstructor, t, this)
     }
     if (kmConstructor.flags != ProtoBuf.Constructor.getDefaultInstance().flags) {
         t.flags = kmConstructor.flags
@@ -125,14 +124,18 @@ private fun WriteContext.writeFunction(kmFunction: KmFunction): ProtoBuf.Functio
     val t = ProtoBuf.Function.newBuilder()
     t.addAllTypeParameter(kmFunction.typeParameters.map { writeTypeParameter(it).build() })
     kmFunction.receiverParameterType?.let { t.receiverType = writeType(it).build() }
+
     @OptIn(ExperimentalContextReceivers::class)
     t.addAllContextReceiverType(kmFunction.contextReceiverTypes.map { writeType(it).build() })
     t.addAllValueParameter(kmFunction.valueParameters.map { writeValueParameter(it).build() })
     t.returnType = writeType(kmFunction.returnType).build()
     t.addAllVersionRequirement(kmFunction.versionRequirements.map(::writeVersionRequirement))
+
     @OptIn(ExperimentalContracts::class)
     kmFunction.contract?.let { t.contract = writeContract(it) }
-    kmFunction.extensions.writeExtensions { writeFunctionExtensions(it, t, this@writeFunction) }
+
+    extensions.forEach { it.writeFunctionExtensions(kmFunction, t, this) }
+
     t.name = this[kmFunction.name]
     if (kmFunction.flags != ProtoBuf.Function.getDefaultInstance().flags) {
         t.flags = kmFunction.flags
@@ -148,12 +151,15 @@ public fun WriteContext.writeProperty(kmProperty: KmProperty): ProtoBuf.Property
         t.addTypeParameter(writeTypeParameter(tp).build())
     }
     kmProperty.receiverParameterType?.let { t.receiverType = writeType(it).build() }
+
     @OptIn(ExperimentalContextReceivers::class)
     t.addAllContextReceiverType(kmProperty.contextReceiverTypes.map { writeType(it).build() })
     kmProperty.setterParameter?.let { t.setterValueParameter = writeValueParameter(it).build() }
     t.returnType = writeType(kmProperty.returnType).build()
     t.addAllVersionRequirement(kmProperty.versionRequirements.map { writeVersionRequirement(it) })
-    kmProperty.extensions.writeExtensions { writePropertyExtensions(it, t, this@writeProperty) }
+
+    extensions.forEach { it.writePropertyExtensions(kmProperty, t, this) }
+
     t.name = this[kmProperty.name]
     if (kmProperty.flags != ProtoBuf.Property.getDefaultInstance().flags) {
         t.flags = kmProperty.flags
@@ -170,7 +176,7 @@ private fun WriteContext.writeValueParameter(
     val t = ProtoBuf.ValueParameter.newBuilder()
     t.type = writeType(kmValueParameter.type).build()
     kmValueParameter.varargElementType?.let { t.varargElementType = writeType(it).build() }
-    kmValueParameter.extensions.writeExtensions { writeValueParameterExtensions(it, t, this@writeValueParameter) }
+    extensions.forEach { it.writeValueParameterExtensions(kmValueParameter, t, this) }
     if (kmValueParameter.flags != ProtoBuf.ValueParameter.getDefaultInstance().flags) {
         t.flags = kmValueParameter.flags
     }
@@ -187,7 +193,7 @@ private fun WriteContext.writeTypeAlias(
     t.expandedType = writeType(typeAlias.expandedType).build()
     t.addAllAnnotation(typeAlias.annotations.map { it.writeAnnotation(strings).build() })
     t.addAllVersionRequirement(typeAlias.versionRequirements.map(::writeVersionRequirement))
-    typeAlias.extensions.writeExtensions { writeTypeAliasExtensions(it, t, this@writeTypeAlias) }
+    extensions.forEach { it.writeTypeAliasExtensions(typeAlias, t, this) }
 
     if (typeAlias.flags != ProtoBuf.TypeAlias.getDefaultInstance().flags) {
         t.flags = typeAlias.flags
@@ -232,7 +238,7 @@ private fun WriteContext.writeVersionRequirement(kmVersionRequirement: KmVersion
         writeVersionFull = { t!!.versionFull = it }
     )
 
-    return this.versionRequirements[t] //??
+    return this.versionRequirements[t]
 }
 
 @ExperimentalContracts
@@ -324,7 +330,8 @@ public open class ClassWriter(stringTable: StringTable, contextExtensions: List<
         t.addAllContextReceiverType(kmClass.contextReceiverTypes.map { c.writeType(it).build() })
 
         t.addAllVersionRequirement(kmClass.versionRequirements.map { c.writeVersionRequirement(it) })
-        kmClass.extensions.matchExtensions { writeClassExtensions(it, t, c) }
+
+        c.extensions.forEach { it.writeClassExtensions(kmClass, t, c) }
 
         c.versionRequirements.serialize()?.let {
             t.versionRequirementTable = it
@@ -340,7 +347,7 @@ public open class PackageWriter(stringTable: StringTable, contextExtensions: Lis
         t.addAllFunction(kmPackage.functions.map { c.writeFunction(it).build() })
         t.addAllProperty(kmPackage.properties.map { c.writeProperty(it).build() })
         t.addAllTypeAlias(kmPackage.typeAliases.map { c.writeTypeAlias(it).build() })
-        kmPackage.extensions.matchExtensions { writePackageExtensions(it, t, c) }
+        c.extensions.forEach { it.writePackageExtensions(kmPackage, t, c) }
         c.versionRequirements.serialize()?.let {
             t.versionRequirementTable = it
         }
@@ -364,7 +371,7 @@ public open class ModuleFragmentWriter(stringTable: StringTable, contextExtensio
             t.addClass_(classWriter.t)
         }
 
-        kmPackageFragment.extensions.writeExtensions { writeModuleFragmentExtensions(it, t, c) }
+        c.extensions.forEach { it.writeModuleFragmentExtensions(kmPackageFragment, t, c) }
     }
 }
 

libraries/kotlinx-metadata/src/kotlinx/metadata/internal/common/KotlinCommonMetadata.kt

@@ -2,7 +2,7 @@
  * Copyright 2010-2022 JetBrains s.r.o. and Kotlin Programming Language contributors.
  * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
  */
-@file:Suppress("DEPRECATION_ERROR")
+@file:Suppress("DEPRECATION_ERROR") // deprecated .accept implementation
 
 package kotlinx.metadata.internal.common
 
@@ -23,9 +23,9 @@ import java.io.ByteArrayInputStream
  * Usually such metadata comes from serialized klibs. However, special `kotlin_builtins` file from standard library
  * distribution can also be read with this reader.
  */
-public class KotlinCommonMetadata private constructor(private val proto: ProtoBuf.PackageFragment) {
+public class KotlinCommonMetadata private constructor(proto: ProtoBuf.PackageFragment) {
 
-    public val kmModuleFragment: KmModuleFragment = readImpl()
+    public val kmModuleFragment: KmModuleFragment = readImpl(proto)
 
     @Deprecated(
         "To avoid excessive copying, use .kmModuleFragment property instead. Note that it returns a view and not a copy.",
@@ -43,7 +43,7 @@ public class KotlinCommonMetadata private constructor(private val proto: ProtoBu
     @Deprecated(VISITOR_API_MESSAGE, level = DeprecationLevel.ERROR)
     public fun accept(v: KmModuleFragmentVisitor): Unit = kmModuleFragment.accept(v)
 
-    private fun readImpl(): KmModuleFragment {
+    private fun readImpl(proto: ProtoBuf.PackageFragment): KmModuleFragment {
         val v = KmModuleFragment()
         val strings = NameResolverImpl(proto.strings, proto.qualifiedNames)
         if (proto.hasPackage()) {

libraries/kotlinx-metadata/src/kotlinx/metadata/internal/extensions/ExtensionNodes.kt

@@ -2,7 +2,7 @@
  * Copyright 2010-2022 JetBrains s.r.o. and Kotlin Programming Language contributors.
  * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
  */
-@file:Suppress("DEPRECATION_ERROR")
+@file:Suppress("DEPRECATION_ERROR") // deprecated visitors API
 
 package kotlinx.metadata.internal.extensions
 

libraries/kotlinx-metadata/src/kotlinx/metadata/internal/extensions/ExtensionUtils.kt

@@ -2,34 +2,10 @@
  * Copyright 2010-2022 JetBrains s.r.o. and Kotlin Programming Language contributors.
  * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
  */
-@file:Suppress("DEPRECATION_ERROR")
+@file:Suppress("DEPRECATION_ERROR") // KmExtensionType will be moved to an internal package
 package kotlinx.metadata.internal.extensions
 
 import kotlinx.metadata.KmExtensionType
-import kotlinx.metadata.KmExtensionVisitor
-
-internal fun <T : KmExtensionVisitor> applySingleExtension(type: KmExtensionType, block: MetadataExtensions.() -> T?): T? {
-    var result: T? = null
-    for (extension in MetadataExtensions.INSTANCES) {
-        val current = block(extension) ?: continue
-        if (result != null) {
-            throw IllegalStateException("Multiple extensions handle the same extension type: $type")
-        }
-        result = current
-    }
-    return result
-}
-
-internal fun <E : KmExtension<*>> List<E>.matchExtensions(block: MetadataExtensions.(E) -> Boolean) {
-    forEach { ext ->
-        var processed = false
-        for (extesion in MetadataExtensions.INSTANCES) {
-            val current = extesion.block(ext)
-            if (processed && current) throw IllegalStateException("Multiple extensions handle the same extension type: ${ext.type}")
-            processed = current
-        }
-    }
-}
 
 internal fun <N : KmExtension<*>> Collection<N>.singleOfType(type: KmExtensionType): N {
     var result: N? = null

libraries/kotlinx-metadata/src/kotlinx/metadata/internal/extensions/MetadataExtensions.kt

@@ -11,55 +11,54 @@ import kotlinx.metadata.internal.common.*
 import org.jetbrains.kotlin.metadata.ProtoBuf
 import java.util.*
 
-@Suppress("DEPRECATION_ERROR")
 public interface MetadataExtensions {
-    public fun readClassExtensions(v: KmClassVisitor, proto: ProtoBuf.Class, c: ReadContext)
+    public fun readClassExtensions(kmClass: KmClass, proto: ProtoBuf.Class, c: ReadContext)
 
-    public fun readPackageExtensions(v: KmPackageVisitor, proto: ProtoBuf.Package, c: ReadContext)
+    public fun readPackageExtensions(kmPackage: KmPackage, proto: ProtoBuf.Package, c: ReadContext)
 
-    public fun readModuleFragmentExtensions(v: KmModuleFragmentVisitor, proto: ProtoBuf.PackageFragment, c: ReadContext)
+    public fun readModuleFragmentExtensions(kmModuleFragment: KmModuleFragment, proto: ProtoBuf.PackageFragment, c: ReadContext)
 
-    public fun readFunctionExtensions(v: KmFunctionVisitor, proto: ProtoBuf.Function, c: ReadContext)
+    public fun readFunctionExtensions(kmFunction: KmFunction, proto: ProtoBuf.Function, c: ReadContext)
 
-    public fun readPropertyExtensions(v: KmPropertyVisitor, proto: ProtoBuf.Property, c: ReadContext)
+    public fun readPropertyExtensions(kmProperty: KmProperty, proto: ProtoBuf.Property, c: ReadContext)
 
-    public fun readConstructorExtensions(v: KmConstructorVisitor, proto: ProtoBuf.Constructor, c: ReadContext)
+    public fun readConstructorExtensions(kmConstructor: KmConstructor, proto: ProtoBuf.Constructor, c: ReadContext)
 
-    public fun readTypeParameterExtensions(v: KmTypeParameterVisitor, proto: ProtoBuf.TypeParameter, c: ReadContext)
+    public fun readTypeParameterExtensions(kmTypeParameter: KmTypeParameter, proto: ProtoBuf.TypeParameter, c: ReadContext)
 
-    public fun readTypeExtensions(v: KmTypeVisitor, proto: ProtoBuf.Type, c: ReadContext)
+    public fun readTypeExtensions(kmType: KmType, proto: ProtoBuf.Type, c: ReadContext)
 
-    public fun readTypeAliasExtensions(v: KmTypeAliasVisitor, proto: ProtoBuf.TypeAlias, c: ReadContext)
+    public fun readTypeAliasExtensions(kmTypeAlias: KmTypeAlias, proto: ProtoBuf.TypeAlias, c: ReadContext)
 
-    public fun readValueParameterExtensions(v: KmValueParameterVisitor, proto: ProtoBuf.ValueParameter, c: ReadContext)
+    public fun readValueParameterExtensions(kmValueParameter: KmValueParameter, proto: ProtoBuf.ValueParameter, c: ReadContext)
 
-    public fun writeClassExtensions(extension: KmClassExtension, proto: ProtoBuf.Class.Builder, c: WriteContext): Boolean
+    public fun writeClassExtensions(kmClass: KmClass, proto: ProtoBuf.Class.Builder, c: WriteContext)
 
-    public fun writePackageExtensions(extension: KmPackageExtension, proto: ProtoBuf.Package.Builder, c: WriteContext): Boolean
+    public fun writePackageExtensions(kmPackage: KmPackage, proto: ProtoBuf.Package.Builder, c: WriteContext)
 
     public fun writeModuleFragmentExtensions(
-        type: KmExtensionType, proto: ProtoBuf.PackageFragment.Builder, c: WriteContext
+        kmModuleFragment: KmModuleFragment, proto: ProtoBuf.PackageFragment.Builder, c: WriteContext
-    ): KmModuleFragmentExtensionVisitor?
+    )
 
-    public fun writeFunctionExtensions(type: KmExtensionType, proto: ProtoBuf.Function.Builder, c: WriteContext): KmFunctionExtensionVisitor?
+    public fun writeFunctionExtensions(kmFunction: KmFunction, proto: ProtoBuf.Function.Builder, c: WriteContext)
 
-    public fun writePropertyExtensions(type: KmExtensionType, proto: ProtoBuf.Property.Builder, c: WriteContext): KmPropertyExtensionVisitor?
+    public fun writePropertyExtensions(kmProperty: KmProperty, proto: ProtoBuf.Property.Builder, c: WriteContext)
 
     public fun writeConstructorExtensions(
-        type: KmExtensionType, proto: ProtoBuf.Constructor.Builder, c: WriteContext
+        kmConstructor: KmConstructor, proto: ProtoBuf.Constructor.Builder, c: WriteContext
-    ): KmConstructorExtensionVisitor?
+    )
 
     public fun writeTypeParameterExtensions(
-        type: KmExtensionType, proto: ProtoBuf.TypeParameter.Builder, c: WriteContext
+        kmTypeParameter: KmTypeParameter, proto: ProtoBuf.TypeParameter.Builder, c: WriteContext
-    ): KmTypeParameterExtensionVisitor?
+    )
 
-    public fun writeTypeExtensions(type: KmExtensionType, proto: ProtoBuf.Type.Builder, c: WriteContext): KmTypeExtensionVisitor?
+    public fun writeTypeExtensions(type: KmType, proto: ProtoBuf.Type.Builder, c: WriteContext)
 
-    public fun writeTypeAliasExtensions(type: KmExtensionType, proto: ProtoBuf.TypeAlias.Builder, c: WriteContext): KmTypeAliasExtensionVisitor?
+    public fun writeTypeAliasExtensions(typeAlias: KmTypeAlias, proto: ProtoBuf.TypeAlias.Builder, c: WriteContext)
 
     public fun writeValueParameterExtensions(
-        type: KmExtensionType, proto: ProtoBuf.ValueParameter.Builder, c: WriteContext
+        valueParameter: KmValueParameter, proto: ProtoBuf.ValueParameter.Builder, c: WriteContext
-    ): KmValueParameterExtensionVisitor?
+    )
 
     public fun createClassExtension(): KmClassExtension
 

libraries/tools/kotlinp/test/org/jetbrains/kotlin/kotlinp/test/KotlinpTestUtils.kt

@@ -81,10 +81,10 @@ private fun compileAndPrintAllFiles(
             "class" -> {
                 val metadata = kotlinp.readClassFile(outputFile)
                 val classFile = kotlinp.readMetadata(metadata)
-                val classFile3 = KotlinClassMetadata.read(transformClassFileWithNodes(metadata, classFile))
+                val classFile2 = KotlinClassMetadata.read(transformClassFileWithNodes(metadata, classFile))
 
                 for ((sb, classFileToRender) in listOf(
-                    main to classFile, afterNodes to classFile3
+                    main to classFile, afterNodes to classFile2
                 )) {
                     sb.appendFileName(outputFile.relativeTo(tmpdir))
                     sb.append(kotlinp.renderClassFile(classFileToRender))