[stub builder] introduce a separate testsuite where classfiles generated by the K2 compiler

The result of k1/k2 should be similar here, the differences should be fixed by KT-60764

analysis/decompiled/decompiler-to-file-stubs/tests/org/jetbrains/kotlin/analysis/decompiler/stub/files/AbstractAdditionalStubInfoK2CompilerTest.kt

@@ -0,0 +1,10 @@
+/*
+ * 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.
+ */
+
+package org.jetbrains.kotlin.analysis.decompiler.stub.files
+
+abstract class AbstractAdditionalStubInfoK2CompilerTest : AbstractAdditionalStubInfoTest() {
+    override val useK2ToCompileCode = true
+}

analysis/decompiled/decompiler-to-file-stubs/tests/org/jetbrains/kotlin/analysis/decompiler/stub/files/AbstractAdditionalStubInfoTest.kt

@@ -22,7 +22,8 @@ abstract class AbstractAdditionalStubInfoTest : AbstractDecompiledClassTest() {
         val stub = KotlinClsStubBuilder().buildFileStub(FileContentImpl.createByFile(getClassFileToDecompile(testData, false)))!!
         val builder = StringBuilder()
         extractAdditionInfo(stub, builder, 0)
-        KotlinTestUtils.assertEqualsToFile(testData.expectedFile, builder.toString())
+        KotlinTestUtils.assertEqualsToFile(testData.getExpectedFile(useK2ToCompileCode), builder.toString())
+        testData.checkIfIdentical(useK2ToCompileCode)
     }
 
     private fun extractAdditionInfo(stub: StubElement<*>, builder: StringBuilder, level: Int) {

analysis/decompiled/decompiler-to-file-stubs/tests/org/jetbrains/kotlin/analysis/decompiler/stub/files/AbstractClsStubBuilderK2CompilerTest.kt

@@ -0,0 +1,10 @@
+/*
+ * 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.
+ */
+
+package org.jetbrains.kotlin.analysis.decompiler.stub.files
+
+abstract class AbstractClsStubBuilderK2CompilerTest : AbstractClsStubBuilderTest() {
+    override val useK2ToCompileCode: Boolean = true
+}

analysis/decompiled/decompiler-to-file-stubs/tests/org/jetbrains/kotlin/analysis/decompiler/stub/files/AbstractDecompiledClassTest.kt

@@ -9,23 +9,29 @@ import com.intellij.core.CoreApplicationEnvironment
 import com.intellij.openapi.vfs.VfsUtilCore
 import com.intellij.openapi.vfs.VirtualFile
 import com.intellij.openapi.vfs.impl.jar.CoreJarFileSystem
-import org.jetbrains.kotlin.analysis.decompiler.stub.file.CachedAttributeData
 import org.jetbrains.kotlin.analysis.decompiler.stub.file.ClsKotlinBinaryClassCache
 import org.jetbrains.kotlin.analysis.decompiler.stub.file.DummyFileAttributeService
 import org.jetbrains.kotlin.analysis.decompiler.stub.file.FileAttributeService
 import org.jetbrains.kotlin.cli.jvm.compiler.KotlinCoreEnvironment
+import org.jetbrains.kotlin.config.LanguageVersion
 import org.jetbrains.kotlin.test.*
+import org.jetbrains.kotlin.test.directives.FirDiagnosticsDirectives
+import org.jetbrains.kotlin.test.services.TestServices
+import org.jetbrains.kotlin.test.utils.FirIdenticalCheckerHelper
 import org.jetbrains.kotlin.utils.addIfNotNull
-import java.io.DataInput
-import java.io.DataOutput
 import java.nio.file.Files
 import java.nio.file.Path
 import java.util.stream.Collectors
 import kotlin.io.path.absolutePathString
 import kotlin.io.path.name
 import kotlin.io.path.readText
+import org.jetbrains.kotlin.test.services.JUnit5Assertions
+import java.io.File
+import org.jetbrains.kotlin.test.services.AssertionsService
 
 abstract class AbstractDecompiledClassTest : KotlinTestWithEnvironment() {
+    protected open val useK2ToCompileCode: Boolean = false
+
     override fun createEnvironment(): KotlinCoreEnvironment {
         return KotlinTestUtils.createEnvironmentWithMockJdkAndIdeaAnnotations(
             ApplicationEnvironmentDisposer.ROOT_DISPOSABLE,
@@ -55,6 +61,7 @@ abstract class AbstractDecompiledClassTest : KotlinTestWithEnvironment() {
                 this.add("-Xuse-type-table")
             }
             this.addAll(testData.additionalCompilerOptions)
+            addAll(listOf("-language-version", getLanguageVersionToCompile().versionString))
         }
         val library = CompilerTestUtil.compileJvmLibrary(
             src = testData.directory.toFile(),
@@ -65,6 +72,16 @@ abstract class AbstractDecompiledClassTest : KotlinTestWithEnvironment() {
         )
     }
 
+    private fun getLanguageVersionToCompile(): LanguageVersion {
+        return if (useK2ToCompileCode) {
+            val k2Version = maxOf(LanguageVersion.LATEST_STABLE, LanguageVersion.KOTLIN_2_0)
+            check(k2Version.usesK2)
+            k2Version
+        } else {
+            LanguageVersion.KOTLIN_1_9
+        }
+    }
+
     private fun findClassFileByName(library: Path, className: String): VirtualFile {
         val jarFileSystem = environment.projectEnvironment.environment.jarFileSystem as CoreJarFileSystem
         val root = jarFileSystem.refreshAndFindFileByPath(library.absolutePathString() + "!/")!!
@@ -93,6 +110,37 @@ internal data class TestData(
     val jvmFileName: String,
     val additionalCompilerOptions: List<String>,
 ) {
+    fun containsDirective(directive: String): Boolean {
+        return InTextDirectivesUtils.isDirectiveDefined(mainKotlinFile.readText(), "// $directive")
+    }
+
+    fun <R : Any> withFirIgnoreDirective(action: () -> R): R? {
+        val directive = "FIR_IGNORE"
+        if (containsDirective(directive)) return null
+        return action()
+    }
+
+
+    fun getExpectedFile(useK2: Boolean): Path {
+        if (useK2) {
+            IdenticalCheckerHelper.getFirFileToCompare(expectedFile.toFile()).takeIf { it.exists() }?.let { return it.toPath() }
+        }
+        return expectedFile
+    }
+
+    fun checkIfIdentical(useK2: Boolean) {
+        if (containsDirective(FirDiagnosticsDirectives.FIR_IDENTICAL.name)) {
+            return
+        }
+        if (useK2) {
+            if (IdenticalCheckerHelper.firAndClassicContentsAreEquals(expectedFile.toFile())) {
+                IdenticalCheckerHelper.deleteFirFile(expectedFile.toFile())
+                IdenticalCheckerHelper.addDirectiveToClassicFileAndAssert(mainKotlinFile.toFile())
+            }
+        }
+    }
+
+
     companion object {
         fun createFromDirectory(directory: Path): TestData {
             val allFiles = Files.list(directory).collect(Collectors.toList())
@@ -111,5 +159,23 @@ internal data class TestData(
             )
         }
     }
+
+    private object IdenticalCheckerHelper : FirIdenticalCheckerHelper(
+        TestServices().apply {
+            register(AssertionsService::class, JUnit5Assertions)
+        }
+    ) {
+        override fun getClassicFileToCompare(testDataFile: File): File {
+            val path = testDataFile.toPath()
+            val fileNameWithoutExtension = path.fileName.toString().removeSuffix(".k2.txt").removeSuffix(".txt")
+            return path.parent.resolve("$fileNameWithoutExtension.txt").toFile()
+        }
+
+        override fun getFirFileToCompare(testDataFile: File): File {
+            val path = testDataFile.toPath()
+            val fileNameWithoutExtension = path.fileName.toString().removeSuffix(".k2.txt").removeSuffix(".txt")
+            return path.parent.resolve("$fileNameWithoutExtension.k2.txt").toFile()
+        }
+    }
 }
 

analysis/decompiled/decompiler-to-file-stubs/tests/org/jetbrains/kotlin/analysis/decompiler/stub/files/AbstractStubBuilderTest.kt

@@ -19,9 +19,10 @@ abstract class AbstractStubBuilderTest : AbstractDecompiledClassTest() {
     fun runTest(testDirectory: String) {
         val testDirectoryPath = Paths.get(testDirectory)
         val testData = TestData.createFromDirectory(testDirectoryPath)
-
-        doTest(testData, useStringTable = true)
-        doTest(testData, useStringTable = false)
+        testData.withFirIgnoreDirective {
+            doTest(testData, useStringTable = true)
+            doTest(testData, useStringTable = false)
+        }
     }
 
 
@@ -31,7 +32,9 @@ abstract class AbstractStubBuilderTest : AbstractDecompiledClassTest() {
     }
 
     private fun testClsStubsForFile(classFile: VirtualFile, testData: TestData) {
-        KotlinTestUtils.assertEqualsToFile(testData.expectedFile, getStubToTest(classFile).serializeToString())
+        val stub = getStubToTest(classFile)
+        KotlinTestUtils.assertEqualsToFile(testData.getExpectedFile(useK2ToCompileCode), stub.serializeToString())
+        testData.checkIfIdentical(useK2ToCompileCode)
     }
 
     protected abstract fun getStubToTest(classFile: VirtualFile): PsiFileStub<*>

analysis/decompiled/decompiler-to-psi/tests/org/jetbrains/kotlin/analysis/decompiler/psi/AbstractByDecompiledPsiStubBuilderK2CompilerTest.kt

@@ -0,0 +1,10 @@
+/*
+ * 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.
+ */
+
+package org.jetbrains.kotlin.analysis.decompiler.psi
+
+abstract class AbstractByDecompiledPsiStubBuilderK2CompilerTest : AbstractByDecompiledPsiStubBuilderTest() {
+    override val useK2ToCompileCode: Boolean = true
+}