UPDATE_KOTLIN_VERSION: 2.1.0-Beta2

build.gradle.kts

@@ -1,5 +1,6 @@
 import com.google.devtools.ksp.configureKtlint
 import com.google.devtools.ksp.configureKtlintApplyToIdea
+import org.jetbrains.kotlin.gradle.dsl.KotlinVersion
 
 val sonatypeUserName: String? by project
 val sonatypePassword: String? by project
@@ -124,5 +125,9 @@ subprojects {
 
     tasks.withType<org.jetbrains.kotlin.gradle.tasks.KotlinCompile>().configureEach {
         compilerOptions.freeCompilerArgs.add("-Xskip-prerelease-check")
+
+        // For access to internal classes.
+        // FIXME: get rid of internal accesses
+        compilerOptions.languageVersion.set(KotlinVersion.KOTLIN_1_9)
     }
 }

compiler-plugin/src/main/kotlin/com/google/devtools/ksp/KotlinSymbolProcessingExtension.kt

@@ -50,8 +50,10 @@ import com.intellij.openapi.vfs.StandardFileSystems
 import com.intellij.openapi.vfs.VirtualFileManager
 import com.intellij.psi.PsiJavaFile
 import com.intellij.psi.PsiManager
+import com.intellij.psi.impl.file.impl.JavaFileManager
 import org.jetbrains.kotlin.analyzer.AnalysisResult
 import org.jetbrains.kotlin.cli.common.messages.CompilerMessageSeverity
+import org.jetbrains.kotlin.cli.jvm.compiler.KotlinCliJavaFileManagerImpl
 import org.jetbrains.kotlin.config.JvmAnalysisFlags
 import org.jetbrains.kotlin.config.LanguageVersionSettings
 import org.jetbrains.kotlin.container.ComponentProvider
@@ -157,6 +159,8 @@ abstract class AbstractKotlinSymbolProcessingExtension(
         val psiManager = PsiManager.getInstance(project)
         if (initialized) {
             psiManager.dropPsiCaches()
+            psiManager.dropResolveCaches()
+            invalidateKotlinCliJavaFileManagerCache(project)
         } else {
             // In case of broken builds.
             if (javaShadowBase.exists()) {
@@ -503,3 +507,13 @@ fun findTargetInfos(languageVersionSettings: LanguageVersionSettings, module: Mo
             else -> UnknownPlatformInfoImpl(platform.toString())
         }
     } ?: emptyList()
+
+// FIXME: remove as soon as possible.
+private fun invalidateKotlinCliJavaFileManagerCache(project: Project): Boolean {
+    val javaFileManager = (JavaFileManager.getInstance(project) as? KotlinCliJavaFileManagerImpl) ?: return false
+    val privateCacheField = KotlinCliJavaFileManagerImpl::class.java.getDeclaredField("topLevelClassesCache")
+    if (!privateCacheField.trySetAccessible())
+        return false
+    (privateCacheField.get(javaFileManager) as? MutableMap<*, *>)?.clear() ?: return false
+    return true
+}

gradle-plugin/src/main/kotlin/com/google/devtools/ksp/gradle/KotlinFactories.kt

@@ -163,7 +163,7 @@ class KotlinFactories {
                         from = compilerOptions,
                         into = kspTask.compilerOptions
                     )
-                    kspTask.produceUnpackedKlib.set(false)
+                    kspTask.produceUnpackagedKlib.set(false)
                     kspTask.onlyIf {
                         // KonanTarget is not properly serializable, hence we should check by name
                         // see https://youtrack.jetbrains.com/issue/KT-61657.

gradle-plugin/src/test/kotlin/com/google/devtools/ksp/gradle/SourceSetConfigurationsTest.kt

@@ -81,7 +81,7 @@ class SourceSetConfigurationsTest {
             """
                 kotlin {
                     jvm { }
-                    android(name = "foo") { }
+                    androidTarget(name = "foo") { }
                     js(IR) { browser() }
                     androidNativeX86 { }
                     androidNativeX64(name = "bar") { }

gradle.properties

@@ -1,7 +1,7 @@
 # Copied from kotlinc
 org.gradle.jvmargs=-Duser.country=US -Dkotlin.daemon.jvm.options=-Xmx4096m -Dfile.encoding=UTF-8
 
-kotlinBaseVersion=2.1.0-Beta1
+kotlinBaseVersion=2.1.0-Beta2
 agpBaseVersion=7.3.1
 intellijVersion=233.13135.103
 junitVersion=4.13.1
@@ -23,5 +23,5 @@ compilerTestEnabled=false
 kotlin.jvm.target.validation.mode=warning
 
 # Build or runtime dependencies of this project
-buildKotlinVersion=1.9.23
-buildKspVersion=1.9.23-1.0.20
+buildKotlinVersion=2.0.21
+buildKspVersion=2.0.21-1.0.25

integration-tests/src/test/kotlin/com/google/devtools/ksp/test/PlaygroundIT.kt

@@ -271,15 +271,15 @@ class PlaygroundIT(val useKSP2: Boolean) {
         val kotlinCompile = "org.jetbrains.kotlin.gradle.tasks.KotlinCompile"
         val buildFile = File(project.root, "workload/build.gradle.kts")
         buildFile.appendText("\ntasks.withType<$kotlinCompile> {")
-        buildFile.appendText("\n    kotlinOptions.apiVersion = \"1.5\"")
-        buildFile.appendText("\n    kotlinOptions.languageVersion = \"1.5\"")
+        buildFile.appendText("\n    kotlinOptions.apiVersion = \"1.6\"")
+        buildFile.appendText("\n    kotlinOptions.languageVersion = \"1.6\"")
         buildFile.appendText("\n}")
 
         val kotlinVersion = System.getProperty("kotlinVersion").split('-').first()
         val gradleRunner = GradleRunner.create().withProjectDir(project.root)
         gradleRunner.buildAndCheck("clean", "build") { result ->
-            Assert.assertTrue(result.output.contains("language version: 1.5"))
-            Assert.assertTrue(result.output.contains("api version: 1.5"))
+            Assert.assertTrue(result.output.contains("language version: 1.6"))
+            Assert.assertTrue(result.output.contains("api version: 1.6"))
             if (!useKSP2) {
                 // In case KSP 1 and KSP 2 uses different compiler versions, ignore this test for KSP 2 for now.
                 Assert.assertTrue(result.output.contains("compiler version: $kotlinVersion"))

integration-tests/src/test/resources/kmp/test-processor/src/main/kotlin/TestProcessor.kt

@@ -67,7 +67,7 @@ class ClassVisitor : KSTopDownVisitor<OutputStreamWriter, Unit>() {
         data: OutputStreamWriter
     ) {
         super.visitClassDeclaration(classDeclaration, data)
-        val symbolName = classDeclaration.simpleName.asString().toLowerCase()
+        val symbolName = classDeclaration.simpleName.asString().lowercase()
         data.write("    val $symbolName = true\n")
     }
 }