Move code conformance tests from compiler tests

#KTI-962
2022-11-03 11:49:51 +01:00
parent dec0946896
commit 080b034950
7 changed files with 37 additions and 19 deletions
@@ -0,0 +1,27 @@
+plugins {
+    kotlin("jvm")
+    id("jps-compatible")
+}
+
+dependencies {
+    testImplementation(intellijCore())
+    testImplementation(projectTests(":compiler:tests-common"))
+
+    testImplementation("com.fasterxml.jackson.dataformat:jackson-dataformat-xml:2.12.7")
+    testImplementation("com.fasterxml.jackson.module:jackson-module-kotlin:2.12.7")
+    testImplementation("com.fasterxml.woodstox:woodstox-core:6.2.4")
+}
+
+sourceSets {
+    "main" {}
+    "test" {
+        projectDefault()
+    }
+}
+
+projectTest() {
+    dependsOn(":dist")
+    workingDir = rootDir
+}
+
+testsJar()
@@ -0,0 +1,410 @@
+/*
+ * 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.code
+
+import com.intellij.openapi.util.io.FileUtil
+import junit.framework.TestCase
+import org.jetbrains.kotlin.config.LanguageFeature
+import java.io.File
+import java.util.*
+import java.util.regex.Pattern
+import kotlin.collections.HashSet
+
+class CodeConformanceTest : TestCase() {
+    companion object {
+        private val JAVA_FILE_PATTERN = Pattern.compile(".+\\.java")
+        private val SOURCES_FILE_PATTERN = Pattern.compile(".+\\.(java|kt|js)")
+        private const val MAX_STEPS_COUNT = 100
+        private val nonSourcesMatcher = FileMatcher(
+            File("."),
+            listOf(
+                ".git",
+                ".idea",
+                "build/js",
+                "build/tmp",
+                "buildSrc",
+                "compiler/build",
+                "compiler/fir/lightTree/testData",
+                "compiler/testData/psi/kdoc",
+                "compiler/tests/org/jetbrains/kotlin/code/CodeConformanceTest.kt",
+                "compiler/util/src/org/jetbrains/kotlin/config/MavenComparableVersion.java",
+                "dependencies",
+                "dependencies/protobuf/protobuf-relocated/build",
+                "dist",
+                "idea/testData/codeInsight/renderingKDoc",
+                "js/js.tests/.gradle",
+                "js/js.tests/build",
+                "js/js.translator/qunit/qunit.js",
+                "js/js.translator/testData/node_modules",
+                "local",
+                "libraries/kotlin.test/js/it/.gradle",
+                "libraries/kotlin.test/js/it/node_modules",
+                "libraries/reflect/api/src/java9/java/kotlin/reflect/jvm/internal/impl",
+                "libraries/reflect/build",
+                "libraries/stdlib/jdk8/moduleTest/NonExportedPackagesTest.kt",
+                "libraries/stdlib/js-ir/.gradle",
+                "libraries/stdlib/js-ir/build",
+                "libraries/stdlib/js-ir-minimal-for-test/.gradle",
+                "libraries/stdlib/js-ir-minimal-for-test/build",
+                "libraries/stdlib/js-v1/.gradle",
+                "libraries/stdlib/js-v1/build",
+                "libraries/tools/binary-compatibility-validator/src/main/kotlin/org.jetbrains.kotlin.tools",
+                "libraries/tools/kotlin-gradle-plugin-core/gradle_api_jar/build/tmp",
+                "libraries/tools/kotlin-gradle-plugin-integration-tests/out",
+                "libraries/tools/kotlin-js-tests/src/test/web/qunit.js",
+                "libraries/tools/kotlin-maven-plugin/target",
+                "libraries/tools/kotlin-source-map-loader/.gradle",
+                "libraries/tools/kotlin-test-js-runner/.gradle",
+                "libraries/tools/kotlin-test-js-runner/lib",
+                "libraries/tools/kotlin-test-js-runner/node_modules",
+                "libraries/tools/kotlin-test-nodejs-runner/.gradle",
+                "libraries/tools/kotlin-test-nodejs-runner/node_modules",
+                "libraries/tools/kotlinp/src",
+                "libraries/tools/new-project-wizard/new-project-wizard-cli/build",
+                "out",
+                "kotlin-native/build",
+                "kotlin-native/performance",
+                "kotlin-native/samples"
+            )
+        )
+
+        private val COPYRIGHT_EXCLUDED_FILES_AND_DIRS_MATCHER = FileMatcher(
+            File("."),
+            listOf(
+                "build",
+                "buildSrc/build/generated-sources",
+                "buildSrc/prepare-deps/build",
+                "compiler/ir/serialization.js/build/fullRuntime",
+                "compiler/ir/serialization.js/build/reducedRuntime/src/libraries/stdlib/js-ir/runtime/longjs.kt",
+                "compiler/tests/org/jetbrains/kotlin/code/CodeConformanceTest.kt",
+                "dependencies",
+                "dependencies/android-sdk/build",
+                "dependencies/protobuf/protobuf-relocated/build",
+                "dist",
+                "idea/idea-jvm/src/org/jetbrains/kotlin/idea/copyright",
+                "js/js.tests/.gradle",
+                "js/js.tests/build",
+                "js/js.translator/testData/node_modules",
+                "libraries/kotlin.test/js/it/.gradle",
+                "libraries/kotlin.test/js/it/node_modules",
+                "libraries/stdlib/common/build",
+                "libraries/stdlib/js-ir/.gradle",
+                "libraries/stdlib/js-ir/build",
+                "libraries/stdlib/js-ir/build/",
+                "libraries/stdlib/js-ir/runtime/longjs.kt",
+                "libraries/stdlib/js-ir-minimal-for-test/.gradle",
+                "libraries/stdlib/js-ir-minimal-for-test/build",
+                "libraries/stdlib/js-v1/.gradle",
+                "libraries/stdlib/js-v1/build",
+                "libraries/stdlib/js-v1/node_modules",
+                "libraries/stdlib/wasm/build",
+                "libraries/tools/kotlin-gradle-plugin-integration-tests/build",
+                "libraries/tools/kotlin-gradle-plugin-integration-tests/.testKitDir",
+                "libraries/tools/kotlin-gradle-plugin-integration-tests/out",
+                "libraries/tools/kotlin-maven-plugin-test/target",
+                "libraries/tools/kotlin-test-js-runner/.gradle",
+                "libraries/tools/kotlin-test-js-runner/lib",
+                "libraries/tools/kotlin-test-js-runner/node_modules",
+                "libraries/tools/kotlin-test-nodejs-runner/.gradle",
+                "libraries/tools/kotlin-test-nodejs-runner/node_modules",
+                "libraries/tools/kotlin-source-map-loader/.gradle",
+                "kotlin-native", "libraries/stdlib/native-wasm", // Have a separate licences manager
+                "out",
+            )
+        )
+    }
+
+    fun testParserCode() {
+        val pattern = Pattern.compile("assert.*?\\b[^_]at.*?$", Pattern.MULTILINE)
+
+        for (sourceFile in FileUtil.findFilesByMask(JAVA_FILE_PATTERN, File("compiler/frontend/src/org/jetbrains/kotlin/parsing"))) {
+            val matcher = pattern.matcher(sourceFile.readText())
+            if (matcher.find()) {
+                fail("An at-method with side-effects is used inside assert: ${matcher.group()}\nin file: $sourceFile")
+            }
+        }
+    }
+
+    private fun isCorrectExtension(filename: String, extensions: Set<String>): Boolean {
+        val additionalExtensions = listOf(
+            "after", "new", "before", "expected",
+            "todo", "delete", "touch", "prefix", "postfix", "map",
+            "fragment", "after2", "result", "log", "messages", "conflicts", "match", "imports", "txt", "xml"
+        )
+        val possibleAdditionalExtensions = extensions.plus(additionalExtensions)
+        val fileExtensions = filename.split("\\.").drop(1)
+        if (fileExtensions.size < 2) {
+            return true
+        }
+        val extension = fileExtensions.last()
+
+        return !((extension !in possibleAdditionalExtensions && (extension.toIntOrNull() ?: MAX_STEPS_COUNT) >= MAX_STEPS_COUNT))
+    }
+
+    fun testForgottenBunchDirectivesAndFiles() {
+        val sourceBunchFilePattern = Pattern.compile("(.+\\.java|.+\\.kt|.+\\.js)(\\.\\w+)?")
+        val root = nonSourcesMatcher.root
+        val extensions = File(root, ".bunch").readLines().map { it.split("_") }.flatten().toSet()
+        val failBuilder = mutableListOf<String>()
+        nonSourcesMatcher.excludeWalkTopDown(sourceBunchFilePattern).forEach { sourceFile ->
+            val matches = Regex("BUNCH (\\w+)")
+                .findAll(sourceFile.readText())
+                .map { it.groupValues[1] }
+                .toSet()
+                .filterNot { it in extensions }
+            for (bunch in matches) {
+                val filename = FileUtil.toSystemIndependentName(sourceFile.toRelativeString(root))
+                failBuilder.add("$filename has unregistered $bunch bunch directive")
+            }
+
+            if (!isCorrectExtension(sourceFile.name, extensions)) {
+                val filename = FileUtil.toSystemIndependentName(sourceFile.toRelativeString(root))
+                failBuilder.add("$filename has unknown bunch extension")
+            }
+        }
+
+        if (failBuilder.isNotEmpty()) {
+            fail("\n" + failBuilder.joinToString("\n"))
+        }
+    }
+
+    fun testNoBadSubstringsInProjectCode() {
+        class TestData(val message: String, val filter: (File, String) -> Boolean) {
+            val result: MutableList<File> = ArrayList()
+        }
+
+        val atAuthorPattern = Pattern.compile("/\\*.+@author.+\\*/", Pattern.DOTALL)
+
+        val tests = listOf(
+            TestData(
+                "%d source files contain @author javadoc tag.\nPlease remove them or exclude in this test:\n%s"
+            ) { _, source ->
+                // substring check is an optimization
+                "@author" in source && atAuthorPattern.matcher(source).find() &&
+                        "ASM: a very small and fast Java bytecode manipulation framework" !in source &&
+                        "package org.jetbrains.kotlin.tools.projectWizard.settings.version.maven" !in source
+            },
+            TestData(
+                "%d source files use something from com.beust.jcommander.internal package.\n" +
+                        "This code won't work when there's no TestNG in the classpath of our IDEA plugin, " +
+                        "because there's only an optional dependency on testng.jar.\n" +
+                        "Most probably you meant to use Guava's Lists, Maps or Sets instead. " +
+                        "Please change references in these files to com.google.common.collect:\n%s"
+            ) { _, source ->
+                "com.beust.jcommander.internal" in source
+            },
+            TestData(
+                "%d source files contain references to package org.jetbrains.jet.\n" +
+                        "Package org.jetbrains.jet is deprecated now in favor of org.jetbrains.kotlin. " +
+                        "Please consider changing the package in these files:\n%s"
+            ) { _, source ->
+                "org.jetbrains.jet" in source
+            },
+            TestData(
+                "%d source files contain references to package kotlin.reflect.jvm.internal.impl.\n" +
+                        "This package contains internal reflection implementation and is a result of a " +
+                        "post-processing of kotlin-reflect.jar by jarjar.\n" +
+                        "Most probably you meant to use classes from org.jetbrains.kotlin.**.\n" +
+                        "Please change references in these files or exclude them in this test:\n%s"
+            ) { _, source ->
+                "kotlin.reflect.jvm.internal.impl" in source
+            },
+            TestData(
+                "%d source files contain references to package org.objectweb.asm.\n" +
+                        "Package org.jetbrains.org.objectweb.asm should be used instead to avoid troubles with different asm versions in classpath. " +
+                        "Please consider changing the package in these files:\n%s"
+            ) { _, source ->
+                " org.objectweb.asm" in source
+            }
+        )
+
+        nonSourcesMatcher.excludeWalkTopDown(SOURCES_FILE_PATTERN).forEach { sourceFile ->
+            val source = sourceFile.readText()
+            for (test in tests) {
+                if (test.filter(sourceFile, source)) test.result.add(sourceFile)
+            }
+        }
+
+        if (tests.flatMap { it.result }.isNotEmpty()) {
+            fail(buildString {
+                for (test in tests) {
+                    if (test.result.isNotEmpty()) {
+                        append(test.message.format(test.result.size, test.result.joinToString("\n")))
+                        appendLine()
+                        appendLine()
+                    }
+                }
+            })
+        }
+    }
+
+    fun testThirdPartyCopyrights() {
+        val filesWithUnlistedCopyrights = mutableListOf<String>()
+        val knownThirdPartyCode = loadKnownThirdPartyCodeList()
+        val copyrightRegex = Regex("""\bCopyright\b""")
+        val root = COPYRIGHT_EXCLUDED_FILES_AND_DIRS_MATCHER.root
+
+        COPYRIGHT_EXCLUDED_FILES_AND_DIRS_MATCHER.excludeWalkTopDown(SOURCES_FILE_PATTERN)
+            .filter { sourceFile ->
+                val relativePath = FileUtil.toSystemIndependentName(sourceFile.toRelativeString(root))
+                !knownThirdPartyCode.any { relativePath.startsWith(it) }
+            }
+            .forEach { sourceFile ->
+                sourceFile.useLines { lineSequence ->
+                    for (line in lineSequence) {
+                        if (copyrightRegex in line && "JetBrains" !in line) {
+                            val relativePath = FileUtil.toSystemIndependentName(sourceFile.toRelativeString(root))
+                            filesWithUnlistedCopyrights.add("$relativePath: $line")
+                        }
+                    }
+                }
+            }
+
+        if (filesWithUnlistedCopyrights.isNotEmpty()) {
+            fail(
+                "The following files contain third-party copyrights and no license information. " +
+                        "Please update license/README.md accordingly:\n${filesWithUnlistedCopyrights.joinToString("\n")}"
+            )
+        }
+    }
+
+    private class FileMatcher(val root: File, paths: Collection<String>) {
+        private val files = paths.map { File(it) }
+        private val paths = files.mapTo(HashSet()) { it.invariantSeparatorsPath }
+        private val relativePaths = files.filterTo(ArrayList()) { it.isDirectory }.mapTo(HashSet()) { it.invariantSeparatorsPath + "/" }
+
+        fun matchExact(file: File): Boolean {
+            return file.relativeTo(root).invariantSeparatorsPath in paths
+        }
+
+        fun matchWithContains(file: File): Boolean {
+            if (matchExact(file)) return true
+            val relativePath = file.relativeTo(root).invariantSeparatorsPath
+            return relativePaths.any { relativePath.startsWith(it) }
+        }
+    }
+
+    private fun FileMatcher.excludeWalkTopDown(filePattern: Pattern): Sequence<File> {
+        return root.walkTopDown()
+            .onEnter { dir ->
+                !matchExact(dir) // Don't enter to ignored dirs
+            }
+            .filter { file -> !matchExact(file) } // filter ignored files
+            .filter { file -> filePattern.matcher(file.name).matches() }
+            .filter { file -> file.isFile }
+    }
+
+    fun testRepositoriesAbuse() {
+        class RepoAllowList(val repo: String, root: File, allowList: Set<String>, val exclude: String? = null) {
+            val matcher = FileMatcher(root, allowList)
+        }
+
+        val root = nonSourcesMatcher.root
+
+        val repoCheckers = listOf(
+            RepoAllowList(
+                // Please use cache-redirector for importing in tests
+                "https://maven.pkg.jetbrains.space/kotlin/p/kotlin/dev", root,
+                setOf("repo/scripts/cache-redirector.settings.gradle.kts")
+            ),
+            RepoAllowList(
+                "https://cache-redirector.jetbrains.com/maven.pkg.jetbrains.space/kotlin/p/kotlin/dev", root,
+                setOf("repo/scripts/cache-redirector.settings.gradle.kts")
+            ),
+            RepoAllowList(
+                // Please use cache-redirector for importing in tests
+                "https://maven.pkg.jetbrains.space/kotlin/p/kotlin/eap", root,
+                setOf("repo/scripts/cache-redirector.settings.gradle.kts")
+            ),
+            RepoAllowList(
+                "https://cache-redirector.jetbrains.com/maven.pkg.jetbrains.space/kotlin/p/kotlin/dev", root,
+                setOf("repo/scripts/cache-redirector.settings.gradle.kts")
+            ),
+            RepoAllowList(
+                "kotlin/ktor", root,
+                setOf("repo/scripts/cache-redirector.settings.gradle.kts")
+            ),
+            RepoAllowList(
+                "bintray.com", root,
+                setOf("repo/scripts/cache-redirector.settings.gradle.kts"),
+                exclude = "jcenter.bintray.com"
+            )
+        )
+
+        data class RepoOccurance(val repo: String, val file: File)
+        data class RepoOccurrences(val repo: String, val files: Collection<File>)
+
+        val extensionsPattern = Pattern.compile(".+\\.(java|kt|gradle|kts|xml)(\\.\\w+)?")
+        val repoOccurrences: List<RepoOccurrences> = nonSourcesMatcher.excludeWalkTopDown(extensionsPattern)
+            .flatMap { file ->
+                val checkers = repoCheckers.filter { checker ->
+                    !checker.matcher.matchWithContains(file)
+                }
+
+                if (checkers.isNotEmpty()) {
+                    val occurrences = ArrayList<RepoOccurance>()
+                    file.useLines { lines ->
+                        for (line in lines) {
+                            for (checker in checkers) {
+                                if (line.contains(checker.repo) && (checker.exclude == null || !line.contains(checker.exclude))) {
+                                    occurrences.add(RepoOccurance(checker.repo, file))
+                                }
+                            }
+                        }
+                    }
+                    occurrences
+                } else {
+                    listOf()
+                }
+            }
+            .groupBy { it.repo }
+            .map { (repo, occurrences) -> RepoOccurrences(repo, occurrences.mapTo(HashSet()) { it.file }) }
+
+        if (repoOccurrences.isNotEmpty()) {
+            val repoOccurrencesStableOrder = repoOccurrences
+                .map { occurrence -> RepoOccurrences(occurrence.repo, occurrence.files.sortedBy { file -> file.path }) }
+                .sortedBy { it.repo }
+            fail(
+                buildString {
+                    appendLine("The following files use repositories and not listed in the correspondent allow lists")
+                    for ((repo, files) in repoOccurrencesStableOrder) {
+                        appendLine(repo)
+                        for (file in files) {
+                            appendLine("  ${file.relativeTo(root).invariantSeparatorsPath}")
+                        }
+                    }
+                }
+            )
+        }
+    }
+
+    private fun loadKnownThirdPartyCodeList(): List<String> {
+        File("license/README.md").useLines { lineSequence ->
+            return lineSequence
+                .filter { it.startsWith(" - Path: ") }
+                .map { it.removePrefix(" - Path: ").trim().ensureFileOrEndsWithSlash() }
+                .toList()
+
+        }
+    }
+
+    fun testLanguageFeatureOrder() {
+        val values = enumValues<LanguageFeature>()
+        val enabledFeatures = values.filter { it.sinceVersion != null }
+
+        if (enabledFeatures.sortedBy { it.sinceVersion!! } != enabledFeatures) {
+            val (a, b) = enabledFeatures.zipWithNext().first { (a, b) -> a.sinceVersion!! > b.sinceVersion!! }
+            fail(
+                "Please make sure LanguageFeature entries are sorted by sinceVersion to improve readability & reduce confusion.\n" +
+                        "The feature $b is out of order; its sinceVersion is ${b.sinceVersion}, yet it comes after $a, whose " +
+                        "sinceVersion is ${a.sinceVersion}.\n"
+            )
+        }
+    }
+}
+
+private fun String.ensureFileOrEndsWithSlash() =
+    if (endsWith("/") || "." in substringAfterLast('/')) this else "$this/"
@@ -0,0 +1,70 @@
+/*
+ * 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.code
+
+import com.fasterxml.jackson.databind.DeserializationFeature
+import com.fasterxml.jackson.dataformat.xml.XmlMapper
+import com.fasterxml.jackson.dataformat.xml.annotation.JacksonXmlElementWrapper
+import com.fasterxml.jackson.dataformat.xml.annotation.JacksonXmlProperty
+import com.fasterxml.jackson.dataformat.xml.annotation.JacksonXmlRootElement
+import com.fasterxml.jackson.module.kotlin.readValue
+import com.fasterxml.jackson.module.kotlin.registerKotlinModule
+import org.jetbrains.kotlin.test.testFramework.KtUsefulTestCase
+import org.junit.Test
+import java.io.File
+
+
+class DepsVerificationMetadataTest {
+    @JacksonXmlRootElement(localName = "verification-metadata")
+    private data class VerificationMetadata(
+        @field:JacksonXmlElementWrapper(localName = "components")
+        val components: List<Component> = listOf()
+    )
+
+    private data class Component(
+        @field:JacksonXmlProperty(isAttribute = true)
+        val group: String,
+        @field:JacksonXmlProperty(isAttribute = true)
+        val name: String,
+        @field:JacksonXmlProperty(isAttribute = true)
+        val version: String,
+        @field:JacksonXmlElementWrapper(useWrapping = false)
+        val artifact: List<Artifact>,
+    )
+
+    private data class Artifact(
+        @field:JacksonXmlProperty(isAttribute = true)
+        val name: String,
+        val md5: Hash?,
+        val sha256: Hash?
+    )
+
+    private data class Hash(@field:JacksonXmlProperty(isAttribute = true) val value: String)
+
+    @Test
+    fun dependenciesHasValidHashes() {
+        val mapper = XmlMapper()
+            .apply {
+                configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false)
+                registerKotlinModule()
+            }
+        val verificationMetadata = mapper.readValue<VerificationMetadata>(File("gradle/verification-metadata.xml"))
+        val fails = mutableListOf<String>()
+
+        verificationMetadata.components.forEach { component ->
+            component.artifact.forEach { artifact ->
+                if (artifact.md5 == null) {
+                    fails.add("${artifact.name} - md5 is missing")
+                }
+                if (artifact.sha256 == null) {
+                    fails.add("${artifact.name} - sha256 is missing")
+                }
+            }
+        }
+
+        KtUsefulTestCase.assertEmpty(fails)
+    }
+}
@@ -0,0 +1,97 @@
+/*
+ * 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.code
+
+import junit.framework.TestCase
+import org.jetbrains.kotlin.codegen.forTestCompile.ForTestCompileRuntime
+import org.jetbrains.kotlin.load.java.JvmAbi
+import java.lang.reflect.Field
+import java.lang.reflect.Modifier
+import kotlin.reflect.jvm.javaField
+
+class ReflectionCodeSanityTest : TestCase() {
+    private lateinit var classLoader: ClassLoader
+
+    override fun setUp() {
+        super.setUp()
+        classLoader = ForTestCompileRuntime.runtimeAndReflectJarClassLoader()
+    }
+
+    override fun tearDown() {
+        ReflectionCodeSanityTest::classLoader.javaField!!.set(this, null)
+        super.tearDown()
+    }
+
+    private fun loadClass(name: String): Class<*> =
+            classLoader.loadClass("kotlin.reflect.jvm.internal.$name")
+
+    private fun collectClassesWithSupers(vararg names: String): Set<Class<*>> {
+        val result = linkedSetOf<Class<*>>()
+        fun addClassToCheck(klass: Class<*>) {
+            if (result.add(klass)) {
+                klass.superclass?.let(::addClassToCheck)
+            }
+        }
+
+        for (name in names) {
+            addClassToCheck(loadClass(name))
+        }
+
+        return result
+    }
+
+    fun testNoDelegatedPropertiesInKClassAndKProperties() {
+        val badFields = linkedSetOf<Field>()
+        for (klass in collectClassesWithSupers(
+                "KClassImpl",
+                "KMutableProperty0Impl",
+                "KMutableProperty1Impl",
+                "KMutableProperty2Impl"
+        )) {
+            badFields.addAll(klass.declaredFields.filter { it.name.endsWith(JvmAbi.DELEGATED_PROPERTY_NAME_SUFFIX) })
+        }
+
+        if (badFields.isNotEmpty()) {
+            fail("The fields listed below appear to be delegates for properties.\n" +
+                 "It's highly not recommended to use property delegates in reflection.jvm because a KProperty instance\n" +
+                 "is created for each delegated property and that makes the initialization sequence of reflection\n" +
+                 "implementation classes unpredictable and leads to a deadlock or ExceptionInInitializerError.\n\n" +
+                 "Please un-delegate the corresponding properties:\n\n" +
+                 badFields.joinToString("\n"))
+        }
+    }
+
+    fun testMaxAllowedFields() {
+        // The following classes are instantiated a lot in Kotlin applications and thus they should be optimized as best as possible.
+        // This test checks that these classes have not more fields than a predefined small number, which can usually be calculated as
+        // the number of constructor parameters (number of objects needed to initialize an instance) + 1 for 'data', the reflection cache.
+        val classesWithMaxAllowedFields = linkedMapOf(
+                "KClassImpl" to 2,   // jClass, data
+                "KPackageImpl" to 3  // jClass, moduleName, data
+        )
+
+        val badClasses = linkedMapOf<Class<*>, Collection<Field>>()
+        for ((className, maxAllowedFields) in classesWithMaxAllowedFields) {
+            val klass = loadClass(className)
+            val fields = generateSequence(klass) { it.superclass }
+                    .flatMap { it.declaredFields.asSequence() }
+                    .filterNot { Modifier.isStatic(it.modifiers) }
+                    .toList()
+            if (fields.size > maxAllowedFields) {
+                badClasses[klass] = fields
+            }
+        }
+
+        if (badClasses.isNotEmpty()) {
+            fail("Some classes in reflection.jvm contain more fields than it is allowed. Please optimize storage in these classes:\n\n" +
+                 badClasses.entries.joinToString("\n") { entry ->
+                     val (klass, fields) = entry
+                     "$klass has ${fields.size} fields but max allowed = ${classesWithMaxAllowedFields[klass.simpleName]}:\n" +
+                     fields.joinToString("\n") { "    $it" }
+                 })
+        }
+    }
+}