HMPP: Fix serialization of TargetPlatform in Kotlin facet

compiler/cli/cli-common/src/org/jetbrains/kotlin/platform/konan/NativePlatform.kt

@@ -10,20 +10,21 @@ import org.jetbrains.kotlin.platform.SimplePlatform
 import org.jetbrains.kotlin.platform.TargetPlatform
 import org.jetbrains.kotlin.platform.toTargetPlatform
 
-sealed class NativePlatform : SimplePlatform("Native")
+sealed class NativePlatform : SimplePlatform("Native") {
+    override val oldFashionedDescription: String
+        get() = toString() + " "
+}
 
 object NativePlatformUnspecifiedTarget : NativePlatform() {
-    override fun toString() = "$platformName (general)"
-
-    override val oldFashionedDescription: String
-        get() = "Native (general) "
+    override val targetName: String
+        get() = "general"
 }
 
 data class NativePlatformWithTarget(val target: KonanTarget) : NativePlatform() {
-    override fun toString() = "$platformName ($target)"
+    override fun toString() = super.toString() // override the method generated for data class
 
-    override val oldFashionedDescription: String
-        get() = "Native ($target) "
+    override val targetName: String
+        get() = target.visibleName
 }
 
 @Suppress("DEPRECATION_ERROR")
@@ -64,3 +65,6 @@ object NativePlatforms {
 }
 
 fun TargetPlatform?.isNative(): Boolean = this?.isNotEmpty() == true && all { it is NativePlatform }
+
+private val legacyNativePlatformUnspecifiedTargetSerializedRepresentation = "${NativePlatformUnspecifiedTarget.platformName} []"
+fun NativePlatformUnspecifiedTarget.legacySerializeToString(): String = legacyNativePlatformUnspecifiedTargetSerializedRepresentation

core/descriptors/src/org/jetbrains/kotlin/platform/TargetPlatform.kt

@@ -57,7 +57,14 @@ open class TargetPlatform(val componentPlatforms: Set<SimplePlatform>) : Collect
  * Ideally, each specific subtype should be either a data class or singleton.
  */
 abstract class SimplePlatform(val platformName: String) {
-    override fun toString(): String = platformName
+    override fun toString(): String {
+        val targetName = targetName
+        return if (targetName.isNotEmpty()) "$platformName ($targetName)" else platformName
+    }
+
+    // description of TargetPlatformVersion or name of custom platform-specific target; used in serialization
+    open val targetName: String
+        get() = targetPlatformVersion.description
 
     /** See KDoc for [TargetPlatform.oldFashionedDescription] */
     abstract val oldFashionedDescription: String
@@ -87,4 +94,4 @@ fun TargetPlatform?.isCommon(): Boolean = this != null && size > 1 && iterator()
 
 fun SimplePlatform.toTargetPlatform(): TargetPlatform = TargetPlatform(setOf(this))
 
-fun SimplePlatform.serializeToString() = "${this.platformName} [${this.targetPlatformVersion.description}]"
+fun SimplePlatform.serializeToString(): String = "$platformName [$targetName]"

core/descriptors/src/org/jetbrains/kotlin/platform/platformUtil.kt

@@ -25,16 +25,16 @@ fun <T> TargetPlatform?.has(klass: Class<T>): Boolean = this != null && subplatf
  * also provides better description for multiplatforms.
  */
 val TargetPlatform.oldFashionedDescription: String
-    // the invocation if isCommon is not preferable as it could be governed by separate flag and may
-    // to appear independently on count of target platforms
+    // this method mistakenly detects "common native" platform as "Common (experimental)"
+    // though this does not seem to have any significant effect
     get() = this.singleOrNull()?.oldFashionedDescription ?: "Common (experimental) "
 
 
 /**
  * Renders multiplatform in form
- *      '$PLATFORM_1 / $PLATFORM_2 / ...'
+ *      '$PLATFORM_1/$PLATFORM_2/...'
  * e.g.
- *      'JVM (1.8) / JS / Native'
+ *      'JVM (1.8)/JS/Native (ios_x64)'
  */
 val TargetPlatform.presentableDescription: String
-    get() = componentPlatforms.joinToString(separator = "/")
+    get() = componentPlatforms.joinToString(separator = "/")

idea/idea-jps-common/src/org/jetbrains/kotlin/config/facetSerialization.kt

@@ -21,6 +21,9 @@ import org.jetbrains.kotlin.platform.js.JsPlatform
 import org.jetbrains.kotlin.platform.jvm.JdkPlatform
 import org.jetbrains.kotlin.platform.jvm.JvmPlatform
 import org.jetbrains.kotlin.platform.konan.NativePlatform
+import org.jetbrains.kotlin.platform.konan.NativePlatformUnspecifiedTarget
+import org.jetbrains.kotlin.platform.konan.NativePlatforms
+import org.jetbrains.kotlin.platform.konan.legacySerializeToString
 import java.lang.reflect.Modifier
 import kotlin.reflect.KClass
 import kotlin.reflect.full.superclasses
@@ -104,19 +107,40 @@ private fun readV1Config(element: Element): KotlinFacetSettings {
     }
 }
 
+// TODO: Introduce new version of facet serialization. See https://youtrack.jetbrains.com/issue/KT-38235
+//  This is necessary to avoid having too much custom logic for platform serialization.
 fun Element.getFacetPlatformByConfigurationElement(): TargetPlatform {
     val platformNames = getAttributeValue("allPlatforms")?.split('/')?.toSet()
-    if (platformNames != null) {
-        return TargetPlatform(CommonPlatforms.allSimplePlatforms
-                                  .flatMap { it.componentPlatforms }
-                                  .filter { platformNames.contains(it.serializeToString()) }
-                                  .toSet())
+    if (platformNames != null && platformNames.isNotEmpty()) {
+        val knownSimplePlatforms = HashMap<String, SimplePlatform>() // serialization presentation to simple platform
+
+        // first, collect serialization presentations for every known simple platform
+        CommonPlatforms.allSimplePlatforms
+            .flatMap { it.componentPlatforms }
+            .forEach { knownSimplePlatforms[it.serializeToString()] = it }
+
+        // next, add legacy aliases for some of the simple platforms; ex: unspecifiedNativePlatform
+        NativePlatformUnspecifiedTarget.let { knownSimplePlatforms[it.legacySerializeToString()] = it }
+
+        val simplePlatforms = platformNames.mapNotNull(knownSimplePlatforms::get)
+        if (simplePlatforms.isNotEmpty()) return TargetPlatform(simplePlatforms.toSet())
+
+        // empty set of simple platforms is not allowed, in such case fallback to legacy algorithm
     }
-    // failed to read list of all platforms. Fallback to legacy algorythm
-    val platformName = getAttributeValue("platform")
-    // this code could be simplified using union after fixing the equals method in SimplePlatform
-    val allPlatforms = ArrayList(CommonPlatforms.allSimplePlatforms).also { it.add(CommonPlatforms.defaultCommonPlatform) }
-    return allPlatforms.firstOrNull { it.oldFashionedDescription == platformName }.orDefault()
+
+    // failed to read list of all platforms. Fallback to legacy algorithm
+    val platformName = getAttributeValue("platform") as String
+
+    return CommonPlatforms.allSimplePlatforms.firstOrNull {
+        // first, look for exact match through all simple platforms
+        it.oldFashionedDescription == platformName
+    } ?: CommonPlatforms.defaultCommonPlatform.takeIf {
+        // then, check exact match for the default common platform
+        it.oldFashionedDescription == platformName
+    } ?: NativePlatforms.unspecifiedNativePlatform.takeIf {
+        // if none of the above succeeded, check if it's an old-style record about native platform (without suffix with target name)
+        it.oldFashionedDescription.startsWith(platformName)
+    }.orDefault() // finally, fallback to the default platform
 }
 
 private fun readV2AndLaterConfig(element: Element): KotlinFacetSettings {
@@ -298,9 +322,14 @@ private fun buildChildElement(element: Element, tag: String, bean: Any, filter:
 private fun KotlinFacetSettings.writeLatestConfig(element: Element) {
     val filter = SkipDefaultsSerializationFilter()
 
-    targetPlatform?.let {
-        element.setAttribute("platform", it.oldFashionedDescription)
-        element.setAttribute("allPlatforms", it.componentPlatforms.map { it.serializeToString() }.sorted().joinToString(separator = "/"))
+    // TODO: Introduce new version of facet serialization. See https://youtrack.jetbrains.com/issue/KT-38235
+    //  This is necessary to avoid having too much custom logic for platform serialization.
+    targetPlatform?.let { targetPlatform ->
+        element.setAttribute("platform", targetPlatform.oldFashionedDescription)
+        element.setAttribute(
+            "allPlatforms",
+            targetPlatform.componentPlatforms.map { it.serializeToString() }.sorted().joinToString(separator = "/")
+        )
     }
     if (!useProjectSettings) {
         element.setAttribute("useProjectSettings", useProjectSettings.toString())