KGP - Fix flaky tests invoking javac through JDK APIs

Tests invoking javac APIs were flaky because ClasspathAnalyzerTest
was using Gradle's ProjectBuilder, which appends tools.jar to
the system class loader. Other tests do not do that, and they
invoke javac APIs directly.

In some executions, this causes some javac classes to be loaded
from the system class loader (the one patched by Gradle), while
some of them will be loaded by UrlClassLoader which points to tools.jar
in java.home. Having javac classes from different class loaders causes
java.lang.IllegalAccessError as package private access across class loaders
is not allowed. https://bugs.openjdk.java.net/browse/JDK-8068152 has more
information on this issue.

This change fixes the issue by fully removing usage of ProjectBuilder.

Test: ClasspathAnalyzerTest

Author: gavra0

libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/internal/kapt/incremental/ClasspathAnalyzer.kt

@@ -54,7 +54,7 @@ abstract class StructureTransformLegacyAction : TransformAction<TransformParamet
     }
 }
 
-private fun transform(input: File, outputs: TransformOutputs) {
+internal fun transform(input: File, outputs: TransformOutputs) {
     val data = if (input.isDirectory) {
         visitDirectory(input)
     } else {

libraries/tools/kotlin-gradle-plugin/src/test/kotlin/org/jetbrains/kotlin/gradle/internal/kapt/incremental/ClasspathAnalyzerTest.kt

@@ -6,10 +6,6 @@
 package org.jetbrains.kotlin.gradle.internal.kapt.incremental
 
 import org.gradle.api.artifacts.transform.TransformOutputs
-import org.gradle.api.artifacts.transform.TransformParameters
-import org.gradle.api.file.FileSystemLocation
-import org.gradle.api.provider.Provider
-import org.gradle.testfixtures.ProjectBuilder
 import org.jetbrains.org.objectweb.asm.ClassWriter
 import org.jetbrains.org.objectweb.asm.Opcodes
 import org.junit.Assert.*
@@ -39,7 +35,7 @@ class ClasspathAnalyzerTest {
             }
         }
         val outputs = TransformOutputsMock(tmp.newFolder())
-        StructureTransformTestAction(classesDir, tmp.newFolder("project")).transform(outputs)
+        transform(classesDir, outputs)
 
         val data = ClasspathEntryData.ClasspathEntrySerializer.loadFrom(outputs.createdOutputs.single())
         assertEquals(setOf("test/A", "test/B"), data.classAbiHash.keys)
@@ -75,7 +71,7 @@ class ClasspathAnalyzerTest {
             }
         }
         val outputs = TransformOutputsMock(tmp.newFolder())
-        StructureTransformTestAction(inputJar, tmp.newFolder("project")).transform(outputs)
+        transform(inputJar, outputs)
 
         val data = ClasspathEntryData.ClasspathEntrySerializer.loadFrom(outputs.createdOutputs.single())
         assertEquals(setOf("test/A", "test/B"), data.classAbiHash.keys)
@@ -101,7 +97,7 @@ class ClasspathAnalyzerTest {
             }
         }
         val outputsA = TransformOutputsMock(tmp.newFolder())
-        StructureTransformTestAction(jarA, tmp.newFolder("projectA")).transform(outputsA)
+        transform(jarA, outputsA)
 
         val jarB = tmp.newFile("inputB.jar").also { jar ->
             ZipOutputStream(jar.outputStream()).use {
@@ -115,17 +111,15 @@ class ClasspathAnalyzerTest {
             }
         }
         val outputsB = TransformOutputsMock(tmp.newFolder())
-        StructureTransformTestAction(jarB, tmp.newFolder("projectB")).transform(outputsB)
+        transform(jarB, outputsB)
 
         assertArrayEquals(outputsA.createdOutputs.single().readBytes(), outputsB.createdOutputs.single().readBytes())
     }
 
     @Test
     fun emptyInput() {
-        val transformAction = StructureTransformTestAction(tmp.newFolder("input"), tmp.newFolder("project"))
         val outputs = TransformOutputsMock(tmp.newFolder())
-
-        transformAction.transform(outputs)
+        transform(tmp.newFolder("input"), outputs)
 
         val data = ClasspathEntryData.ClasspathEntrySerializer.loadFrom(outputs.createdOutputs.single())
         assertTrue(data.classAbiHash.isEmpty())
@@ -149,10 +143,8 @@ class ClasspathAnalyzerTest {
                 it.closeEntry()
             }
         }
-        val transformAction = StructureTransformTestAction(inputJar, tmp.newFolder("project"))
         val outputs = TransformOutputsMock(tmp.newFolder())
-
-        transformAction.transform(outputs)
+        transform(inputJar, outputs)
 
         val data = ClasspathEntryData.ClasspathEntrySerializer.loadFrom(outputs.createdOutputs.single())
         assertEquals(setOf("test/A", "test/B", "test/C"), data.classAbiHash.keys)
@@ -166,17 +158,6 @@ class ClasspathAnalyzerTest {
     }
 }
 
-class StructureTransformTestAction(val input: File, val projectDir: File) : StructureTransformAction() {
-    private val project = ProjectBuilder.builder().withProjectDir(projectDir).build()
-
-    override val inputArtifact: Provider<FileSystemLocation> = project.provider { project.objects.fileProperty().fileValue(input).get() }
-
-    override fun getParameters(): TransformParameters.None? {
-        //no need for StructureTransformAction and so for test
-        return null
-    }
-}
-
 class TransformOutputsMock(val outputDir: File) : TransformOutputs {
     val createdOutputs = mutableListOf<File>()
 
@@ -192,4 +173,4 @@ class TransformOutputsMock(val outputDir: File) : TransformOutputs {
         return newDir
     }
 
-}
+}