Extract shouldWritePreReleaseFlag(), use in JS as well as JVM

Fix the difference in behavior between JS and JVM

compiler/backend/src/org/jetbrains/kotlin/codegen/writeAnnotationUtil.kt

@@ -17,8 +17,7 @@
 package org.jetbrains.kotlin.codegen
 
 import org.jetbrains.kotlin.codegen.state.GenerationState
-import org.jetbrains.kotlin.config.KotlinCompilerVersion
-import org.jetbrains.kotlin.config.LanguageVersion
+import org.jetbrains.kotlin.config.shouldWritePreReleaseFlag
 import org.jetbrains.kotlin.load.java.JvmAnnotationNames
 import org.jetbrains.kotlin.load.java.JvmBytecodeBinaryVersion
 import org.jetbrains.kotlin.load.kotlin.JvmMetadataVersion
@@ -37,9 +36,7 @@ fun writeKotlinMetadata(
     av.visit(JvmAnnotationNames.BYTECODE_VERSION_FIELD_NAME, JvmBytecodeBinaryVersion.INSTANCE.toArray())
     av.visit(JvmAnnotationNames.KIND_FIELD_NAME, kind.id)
     var flags = extraFlags
-    val languageVersion = state.languageVersionSettings.languageVersion
-    if (KotlinCompilerVersion.isPreRelease() && languageVersion == LanguageVersion.LATEST_STABLE ||
-        !languageVersion.isStable) {
+    if (state.languageVersionSettings.shouldWritePreReleaseFlag()) {
         flags = flags or JvmAnnotationNames.METADATA_PRE_RELEASE_FLAG
     }
     if (flags != 0) {
@@ -53,4 +50,4 @@ fun writeSyntheticClassMetadata(cb: ClassBuilder, state: GenerationState) {
     writeKotlinMetadata(cb, state, KotlinClassHeader.Kind.SYNTHETIC_CLASS, 0) { _ ->
         // Do nothing
     }
-}
+}

compiler/tests/org/jetbrains/kotlin/serialization/js/KotlinJavascriptSerializerTest.kt

@@ -24,6 +24,7 @@ import org.jetbrains.kotlin.cli.jvm.compiler.EnvironmentConfigFiles
 import org.jetbrains.kotlin.cli.jvm.compiler.KotlinCoreEnvironment
 import org.jetbrains.kotlin.config.CompilerConfiguration
 import org.jetbrains.kotlin.config.addKotlinSourceRoots
+import org.jetbrains.kotlin.config.languageVersionSettings
 import org.jetbrains.kotlin.descriptors.impl.ModuleDescriptorImpl
 import org.jetbrains.kotlin.incremental.components.LookupTracker
 import org.jetbrains.kotlin.js.analyze.TopDownAnalyzerFacadeForJS
@@ -78,7 +79,9 @@ class KotlinJavascriptSerializerTest : TestCaseWithTmpdir() {
                     imported = listOf(),
                     data = analysisResult.moduleDescriptor
             )
-            FileUtil.writeToFile(metaFile, KotlinJavascriptSerializationUtil.metadataAsString(analysisResult.bindingContext, description))
+            FileUtil.writeToFile(metaFile, KotlinJavascriptSerializationUtil.metadataAsString(
+                    analysisResult.bindingContext, description, configuration.languageVersionSettings
+            ))
         }
         finally {
             Disposer.dispose(rootDisposable)

compiler/util/src/org/jetbrains/kotlin/config/LanguageVersionSettings.kt

@@ -184,3 +184,9 @@ class LanguageVersionSettingsImpl @JvmOverloads constructor(
         val DEFAULT = LanguageVersionSettingsImpl(LanguageVersion.LATEST_STABLE, ApiVersion.LATEST_STABLE)
     }
 }
+
+fun LanguageVersionSettings.shouldWritePreReleaseFlag(): Boolean {
+    if (!languageVersion.isStable) return true
+
+    return KotlinCompilerVersion.isPreRelease() && languageVersion == LanguageVersion.LATEST_STABLE
+}