Use JvmName on kotlin.Metadata parameters to improve public API

#KT-26359 Fixed

compiler/testData/codegen/box/jvmPackageName/metadataField.kt

@@ -12,10 +12,8 @@ fun f() {}
 
 // FILE: bar.kt
 
-@file:Suppress("INVISIBLE_REFERENCE", "INVISIBLE_MEMBER")
-
 fun getPackageName(classFqName: String): String =
-        Class.forName(classFqName).getAnnotation(Metadata::class.java).pn
+    Class.forName(classFqName).getAnnotation(Metadata::class.java).packageName
 
 fun box(): String {
     val bar = getPackageName("BarKt")

compiler/testData/diagnostics/testsWithStdLib/annotations/explicitMetadata.kt

@@ -1,9 +1,9 @@
 <!EXPLICIT_METADATA_IS_DISALLOWED!>@Metadata<!>
 class A
 
-<!EXPLICIT_METADATA_IS_DISALLOWED!>@Metadata(xs = "_")<!>
+<!EXPLICIT_METADATA_IS_DISALLOWED!>@Metadata(extraString = "_")<!>
 annotation class B(val m: Metadata)
 
-<!WRONG_ANNOTATION_TARGET, EXPLICIT_METADATA_IS_DISALLOWED!>@Metadata(xi = 0)<!>
+<!WRONG_ANNOTATION_TARGET, EXPLICIT_METADATA_IS_DISALLOWED!>@Metadata(extraInt = 0)<!>
 @B(Metadata())
 fun f() {}

compiler/testData/diagnostics/testsWithStdLib/annotations/explicitMetadata.txt

@@ -1,6 +1,6 @@
 package
 
-@kotlin.Metadata(xi = 0) @B(m = kotlin.Metadata) public fun f(): kotlin.Unit
+@kotlin.Metadata(extraInt = 0) @B(m = kotlin.Metadata) public fun f(): kotlin.Unit
 
 @kotlin.Metadata public final class A {
     public constructor A()
@@ -9,7 +9,7 @@ package
     public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
 }
 
-@kotlin.Metadata(xs = "_") public final annotation class B : kotlin.Annotation {
+@kotlin.Metadata(extraString = "_") public final annotation class B : kotlin.Annotation {
     public constructor B(/*0*/ m: kotlin.Metadata)
     public final val m: kotlin.Metadata
     public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean

core/metadata.jvm/src/org/jetbrains/kotlin/metadata/jvm/deserialization/JvmProtoBufUtil.kt

@@ -50,7 +50,7 @@ object JvmProtoBufUtil {
         JvmNameResolver(JvmProtoBuf.StringTableTypes.parseDelimitedFrom(this, EXTENSION_REGISTRY), strings)
 
     /**
-     * Serializes [message] and [stringTable] into a string array which must be further written to [Metadata.d1]
+     * Serializes [message] and [stringTable] into a string array which must be further written to [Metadata.data1]
      */
     @JvmStatic
     fun writeData(message: MessageLite, stringTable: JvmStringTable): Array<String> =

core/reflection.jvm/src/kotlin/reflect/jvm/reflectLambda.kt

@@ -14,8 +14,6 @@
  * limitations under the License.
  */
 
-@file:Suppress("INVISIBLE_REFERENCE", "INVISIBLE_MEMBER")
-
 package kotlin.reflect.jvm
 
 import org.jetbrains.kotlin.load.java.JvmAnnotationNames
@@ -35,10 +33,12 @@ import kotlin.reflect.jvm.internal.deserializeToDescriptor
  */
 fun <R> Function<R>.reflect(): KFunction<R>? {
     val annotation = javaClass.getAnnotation(Metadata::class.java) ?: return null
-    val data = annotation.d1.takeUnless(Array<String>::isEmpty) ?: return null
+    val data = annotation.data1.takeUnless(Array<String>::isEmpty) ?: return null
-    val (nameResolver, proto) = JvmProtoBufUtil.readFunctionDataFrom(data, annotation.d2)
+    val (nameResolver, proto) = JvmProtoBufUtil.readFunctionDataFrom(data, annotation.data2)
-    val metadataVersion =
+    val metadataVersion = JvmMetadataVersion(
-        JvmMetadataVersion(annotation.mv, (annotation.xi and JvmAnnotationNames.METADATA_STRICT_VERSION_SEMANTICS_FLAG) != 0)
+        annotation.metadataVersion,
+        (annotation.extraInt and JvmAnnotationNames.METADATA_STRICT_VERSION_SEMANTICS_FLAG) != 0
+    )
 
     val descriptor = deserializeToDescriptor(
         javaClass, proto, nameResolver, TypeTable(proto.typeTable), metadataVersion, MemberDeserializer::loadFunction

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

@@ -10,12 +10,7 @@ import org.jetbrains.kotlin.metadata.jvm.deserialization.JvmMetadataVersion
 
 /**
  * A mirror to the [Metadata] annotation on a JVM class file, containing the metadata of Kotlin declarations declared in the class file.
- * Properties of this class correspond to the properties of [Metadata], but the names are not shortened because there's no restriction
+ * Properties of this class correspond 1:1 to the properties of [Metadata].
- * on the bytecode size here.
- *
- * Note that [Metadata] is not yet public (see https://youtrack.jetbrains.com/issue/KT-23602). In order to create an instance of
- * [KotlinClassHeader] from the [Metadata] annotation instance obtained reflectively, one could use Java code to workaround
- * the internal visibility error.
  *
  * @param kind see [kind]
  * @param metadataVersion see [metadataVersion]
@@ -39,7 +34,7 @@ class KotlinClassHeader(
     /**
      * A kind of the metadata this header encodes.
      *
-     * @see Metadata.k
+     * @see Metadata.kind
      * @see CLASS_KIND
      * @see FILE_FACADE_KIND
      * @see SYNTHETIC_CLASS_KIND
@@ -51,7 +46,7 @@ class KotlinClassHeader(
     /**
      * The version of the metadata provided in other properties of this header.
      *
-     * @see Metadata.mv
+     * @see Metadata.metadataVersion
      * @see COMPATIBLE_METADATA_VERSION
      */
     val metadataVersion: IntArray = metadataVersion ?: intArrayOf()
@@ -59,7 +54,7 @@ class KotlinClassHeader(
     /**
      * The version of the bytecode interface (naming conventions, signatures) of the corresponding class file.
      *
-     * @see Metadata.bv
+     * @see Metadata.bytecodeVersion
      * @see COMPATIBLE_BYTECODE_VERSION
      */
     val bytecodeVersion: IntArray = bytecodeVersion ?: intArrayOf()
@@ -67,35 +62,35 @@ class KotlinClassHeader(
     /**
      * The first array of strings used to encode the metadata.
      *
-     * @see Metadata.d1
+     * @see Metadata.data1
      */
     val data1: Array<String> = data1 ?: emptyArray()
 
     /**
      * The second array of strings used to encode the metadata.
      *
-     * @see Metadata.d2
+     * @see Metadata.data2
      */
     val data2: Array<String> = data2 ?: emptyArray()
 
     /**
      * An extra string field for the metadata.
      *
-     * @see Metadata.xs
+     * @see Metadata.extraString
      */
     val extraString: String = extraString ?: ""
 
     /**
      * Fully qualified name of the Kotlin package of the corresponding class, in case [JvmPackageName] was used.
      *
-     * @see Metadata.pn
+     * @see Metadata.packageName
      */
     val packageName: String = packageName ?: ""
 
     /**
      * An extra int field for the metadata.
      *
-     * @see Metadata.xi
+     * @see Metadata.extraInt
      */
     val extraInt: Int = extraInt ?: 0
 

libraries/kotlinx-metadata/jvm/test/kotlinx/metadata/test/MetadataSmokeTest.kt

@@ -15,10 +15,9 @@ import java.net.URLClassLoader
 import kotlin.reflect.full.primaryConstructor
 
 class MetadataSmokeTest {
-    @Suppress("INVISIBLE_MEMBER", "INVISIBLE_REFERENCE")
     private fun Class<*>.readMetadata(): KotlinClassHeader {
         return getAnnotation(Metadata::class.java).run {
-            KotlinClassHeader(k, mv, bv, d1, d2, xs, pn, xi)
+            KotlinClassHeader(kind, metadataVersion, bytecodeVersion, data1, data2, extraString, packageName, extraInt)
         }
     }
 

libraries/stdlib/jvm/runtime/kotlin/Metadata.kt

@@ -7,7 +7,7 @@ package kotlin
 
 /**
  * This annotation is present on any class file produced by the Kotlin compiler and is read by the compiler and reflection.
- * Parameters have very short names on purpose: these names appear in the generated class files, and we'd like to reduce their size.
+ * Parameters have very short JVM names on purpose: these names appear in all generated class files, and we'd like to reduce their size.
  */
 @Retention(AnnotationRetention.RUNTIME)
 @Target(AnnotationTarget.CLASS)
@@ -24,35 +24,42 @@ public annotation class Metadata(
      *
      * The class file with a kind not listed here is treated as a non-Kotlin file.
      */
-    val k: Int = 1,
+    @get:JvmName("k")
+    val kind: Int = 1,
     /**
      * The version of the metadata provided in the arguments of this annotation.
      */
-    val mv: IntArray = [],
+    @get:JvmName("mv")
+    val metadataVersion: IntArray = [],
     /**
      * The version of the bytecode interface (naming conventions, signatures) of the class file annotated with this annotation.
      */
-    val bv: IntArray = [],
+    @get:JvmName("bv")
+    val bytecodeVersion: IntArray = [],
     /**
      * Metadata in a custom format. The format may be different (or even absent) for different kinds.
      */
-    val d1: Array<String> = [],
+    @get:JvmName("d1")
+    val data1: Array<String> = [],
     /**
      * An addition to [d1]: array of strings which occur in metadata, written in plain text so that strings already present
      * in the constant pool are reused. These strings may be then indexed in the metadata by an integer index in this array.
      */
-    val d2: Array<String> = [],
+    @get:JvmName("d2")
+    val data2: Array<String> = [],
     /**
      * An extra string. For a multi-file part class, internal name of the facade class.
      */
-    val xs: String = "",
+    @get:JvmName("xs")
+    val extraString: String = "",
     /**
      * Fully qualified name of the package this class is located in, from Kotlin's point of view, or empty string if this name
      * does not differ from the JVM's package FQ name. These names can be different in case the [JvmPackageName] annotation is used.
      * Note that this information is also stored in the corresponding module's `.kotlin_module` file.
      */
     @SinceKotlin("1.2")
-    val pn: String = "",
+    @get:JvmName("pn")
+    val packageName: String = "",
     /**
      * An extra int. Bits of this number represent the following flags:
      *
@@ -63,5 +70,6 @@ public annotation class Metadata(
      *   the major.minor version of this metadata ([mv]).
      */
     @SinceKotlin("1.1")
-    val xi: Int = 0
+    @get:JvmName("xi")
+    val extraInt: Int = 0
 )

libraries/tools/kotlinp/src/org/jetbrains/kotlin/kotlinp/readKotlinClassHeader.kt

@@ -6,10 +6,7 @@
 package org.jetbrains.kotlin.kotlinp
 
 import kotlinx.metadata.jvm.KotlinClassHeader
-import org.objectweb.asm.AnnotationVisitor
+import org.objectweb.asm.*
-import org.objectweb.asm.ClassReader
-import org.objectweb.asm.ClassVisitor
-import org.objectweb.asm.Opcodes
 import java.io.File
 import java.io.FileInputStream
 
@@ -17,9 +14,10 @@ internal fun File.readKotlinClassHeader(): KotlinClassHeader? {
     var header: KotlinClassHeader? = null
 
     try {
+        val metadataDesc = Type.getDescriptor(Metadata::class.java)
         ClassReader(FileInputStream(this)).accept(object : ClassVisitor(Opcodes.ASM4) {
             override fun visitAnnotation(desc: String, visible: Boolean): AnnotationVisitor? =
-                if (desc == "Lkotlin/Metadata;") readMetadataVisitor { header = it }
+                if (desc == metadataDesc) readMetadataVisitor { header = it }
                 else null
         }, ClassReader.SKIP_CODE or ClassReader.SKIP_DEBUG or ClassReader.SKIP_FRAMES)
     } catch (e: Exception) {
@@ -29,7 +27,6 @@ internal fun File.readKotlinClassHeader(): KotlinClassHeader? {
     return header
 }
 
-@Suppress("INVISIBLE_MEMBER", "INVISIBLE_REFERENCE")
 private fun readMetadataVisitor(output: (KotlinClassHeader) -> Unit): AnnotationVisitor =
     object : AnnotationVisitor(Opcodes.ASM4) {
         var kind: Int? = null
@@ -43,19 +40,19 @@ private fun readMetadataVisitor(output: (KotlinClassHeader) -> Unit): Annotation
 
         override fun visit(name: String?, value: Any?) {
             when (name) {
-                Metadata::k.name -> kind = value as? Int
+                "k" -> kind = value as? Int
-                Metadata::mv.name -> metadataVersion = value as? IntArray
+                "mv" -> metadataVersion = value as? IntArray
-                Metadata::bv.name -> bytecodeVersion = value as? IntArray
+                "bv" -> bytecodeVersion = value as? IntArray
-                Metadata::xs.name -> extraString = value as? String
+                "xs" -> extraString = value as? String
-                Metadata::xi.name -> extraInt = value as? Int
+                "xi" -> extraInt = value as? Int
-                Metadata::pn.name -> packageName = value as? String
+                "pn" -> packageName = value as? String
             }
         }
 
         override fun visitArray(name: String?): AnnotationVisitor? =
             when (name) {
-                Metadata::d1.name -> stringArrayVisitor { data1 = it }
+                "d1" -> stringArrayVisitor { data1 = it }
-                Metadata::d2.name -> stringArrayVisitor { data2 = it }
+                "d2" -> stringArrayVisitor { data2 = it }
                 else -> null
             }