Allow running tests within a debugger (#25655)

Fix #25633

Also improves the simple ignored-by-default Playground to easily run one test case at a time

## How much have you relied on LLM-based tools in this contribution?

not

## How was the solution tested?

duh

Author: SolalPirelli

compiler/test/dotty/tools/TestSources.scala

@@ -10,6 +10,21 @@ import dotty.Properties
 
 object TestSources {
 
+  private val isWorkingDirectoryInsideCompiler = Paths.get(".").toAbsolutePath.normalize.endsWith("compiler")
+
+  def rootPath(): Path =
+    if isWorkingDirectoryInsideCompiler
+    then Paths.get("..")
+    else Paths.get(".")
+
+  def getPath(relative: String): Path =
+    if isWorkingDirectoryInsideCompiler
+    then Paths.get("..", relative)
+    // important to not do `get(".", relative)` (or equivalently `rootPath().resolve(relative)`),
+    // the rest of the testing framework depends on exact paths,
+    // so "error in ./x.scala" and "error in x.scala" aren't considered equivalent.
+    else Paths.get(relative)
+
   // pos tests lists
 
   def posFromTastyExcludelistFile: String = "compiler/test/dotc/pos-from-tasty.excludelist"
@@ -85,7 +100,7 @@ object TestSources {
   // load lists
 
   private def loadList(path: String): List[String] = {
-    val list = Files.readAllLines(Paths.get(path))
+    val list = Files.readAllLines(getPath(path))
       .iterator()
       .asScala
       .map(_.trim)                     // allow indentation

compiler/test/dotty/tools/dotc/BootstrappedOnlyCompilationTests.scala

@@ -186,7 +186,7 @@ class BootstrappedOnlyCompilationTests {
     // 1. hack with absolute path for -Xplugin
     // 2. copy `pluginFile` to destination
     def compileFilesInDir(dir: String, run: Boolean = false): CompilationTest = {
-      val outDir = defaultOutputDir + "testPlugins/"
+      val outDir = new java.io.File(defaultOutputDir, "testPlugins")
       val sourceDir = new java.io.File(dir)
 
       val dirs = sourceDir.listFiles.toList.filter(_.isDirectory)

compiler/test/dotty/tools/dotc/CompilationTests.scala

@@ -4,35 +4,26 @@ package dotc
 
 import scala.language.unsafeNulls
 
-import org.junit.{ Test, BeforeClass, AfterClass, Ignore }
-import org.junit.Assert._
-import org.junit.Assume._
-import org.junit.experimental.categories.Category
-
-import java.io.File
-import java.nio.file._
-import java.util.stream.{ Stream => JStream }
-import scala.jdk.CollectionConverters._
-import scala.util.matching.Regex
-import scala.concurrent.duration._
-import TestSources.sources
-import TestSources.scoverageIgnoreExcludelisted
-import reporting.TestReporter
-import vulpix._
-import dotty.tools.dotc.config.ScalaSettings
-import dotty.tools.dotc.coverage.Serializer
+import org.junit.{ Test, AfterClass }
+import org.junit.Assume.*
+
+import java.nio.file.*
+import scala.concurrent.duration.*
+
+import dotty.tools.dotc.reporting.TestReporter
+import dotty.tools.vulpix.*
 
 class CompilationTests {
-  import ParallelTesting._
-  import TestConfiguration._
-  import CompilationTests._
+  import ParallelTesting.*
+  import TestConfiguration.*
+  import CompilationTests.*
   import CompilationTest.aggregateTests
 
   // Positive tests ------------------------------------------------------------
 
   @Test def pos: Unit = {
     implicit val testGroup: TestGroup = TestGroup("compilePos")
-    var tests = List(
+    val tests = List(
       compileFilesInDir("tests/pos", defaultOptions.and("-Wsafe-init", "-Wunused:all", "-Wshadow:private-shadow", "-Wshadow:type-parameter-shadow"), FileFilter.include(TestSources.posLintingAllowlist)),
       compileFilesInDir("tests/pos", defaultOptions.and("-Wsafe-init"), FileFilter.exclude(TestSources.posLintingAllowlist)),
       compileFilesInDir("tests/pos-deep-subtype", allowDeepSubtypes),
@@ -279,7 +270,7 @@ class CompilationTests {
     locally {
       val group = TestGroup("checkInitGlobal/tastySource")
       val tastSourceOptions = defaultOptions.and("-Ysafe-init-global")
-      val outDirLib = defaultOutputDir + group + "/A/tastySource/A"
+      val outDirLib = Paths.get(defaultOutputDir.getAbsolutePath, group.name,"A", "tastySource", "A").toString
 
       // Set -sourceroot such that the source code cannot be found by the compiler
       val libOptions = tastSourceOptions.and("-sourceroot", "tests/init-global/special")
@@ -311,8 +302,8 @@ class CompilationTests {
     locally {
       val i12128Group = TestGroup("checkInit/i12128")
       val i12128Options = options.without("-Werror")
-      val outDir1 = defaultOutputDir + i12128Group + "/Reflect_1/i12128/Reflect_1"
-      val outDir2 = defaultOutputDir + i12128Group + "/Macro_2/i12128/Macro_2"
+      val outDir1 = Paths.get(defaultOutputDir.getAbsolutePath, i12128Group.name, "Reflect_1", "i12128", "Reflect_1").toString
+      val outDir2 = Paths.get(defaultOutputDir.getAbsolutePath, i12128Group.name, "Macro_2", "i12128", "Macro_2").toString
 
       val tests = List(
         withCoverage(compileFile("tests/init/special/i12128/Reflect_1.scala", i12128Options)(using i12128Group).keepOutput),
@@ -331,9 +322,9 @@ class CompilationTests {
       val tastyErrorGroup = TestGroup("checkInit/tasty-error/val-or-defdef")
       val tastyErrorOptions = options.without("-Werror")
 
-      val classA0 = defaultOutputDir + tastyErrorGroup + "/A/v0/A"
-      val classA1 = defaultOutputDir + tastyErrorGroup + "/A/v1/A"
-      val classB1 = defaultOutputDir + tastyErrorGroup + "/B/v1/B"
+      val classA0 = Paths.get(defaultOutputDir.getAbsolutePath, tastyErrorGroup.name, "A", "v0", "A").toString
+      val classA1 = Paths.get(defaultOutputDir.getAbsolutePath, tastyErrorGroup.name, "A", "v1", "A").toString
+      val classB1 = Paths.get(defaultOutputDir.getAbsolutePath, tastyErrorGroup.name, "B", "v1", "B").toString
 
       val tests = List(
         withCoverage(compileFile("tests/init/tasty-error/val-or-defdef/v1/A.scala", tastyErrorOptions)(using tastyErrorGroup).keepOutput),
@@ -355,10 +346,10 @@ class CompilationTests {
       val tastyErrorGroup = TestGroup("checkInit/tasty-error/typedef")
       val tastyErrorOptions = options.without("-Werror").without("-Ycheck:all")
 
-      val classC = defaultOutputDir + tastyErrorGroup + "/C/typedef/C"
-      val classA0 = defaultOutputDir + tastyErrorGroup + "/A/v0/A"
-      val classA1 = defaultOutputDir + tastyErrorGroup + "/A/v1/A"
-      val classB1 = defaultOutputDir + tastyErrorGroup + "/B/v1/B"
+      val classC =  Paths.get(defaultOutputDir.getAbsolutePath, tastyErrorGroup.name, "C", "typedef", "C").toString
+      val classA0 = Paths.get(defaultOutputDir.getAbsolutePath, tastyErrorGroup.name, "A", "v0", "A").toString
+      val classA1 = Paths.get(defaultOutputDir.getAbsolutePath, tastyErrorGroup.name, "A", "v1", "A").toString
+      val classB1 = Paths.get(defaultOutputDir.getAbsolutePath, tastyErrorGroup.name, "B", "v1", "B").toString
 
       val tests = List(
         withCoverage(compileFile("tests/init/tasty-error/typedef/C.scala", tastyErrorOptions)(using tastyErrorGroup).keepOutput),

compiler/test/dotty/tools/dotc/Playground.scala

@@ -1,13 +1,23 @@
 package dotty.tools.dotc
 
-import dotty.tools.vulpix._
+import dotty.tools.vulpix.*
 import org.junit.Test
 import org.junit.Ignore
 
+// For ease of debugging individual tests
 @Ignore class Playground:
-  import TestConfiguration._
-  import CompilationTests._
+  import TestConfiguration.*
+  import CompilationTests.*
+  import CompilationTest.aggregateTests
 
   @Test def example: Unit =
-    implicit val testGroup: TestGroup = TestGroup("playground")
-    compileFile("tests/playground/example.scala", defaultOptions).checkCompile()
+    implicit val testGroup: TestGroup = TestGroup("single-test")
+    // can add, e.g., .and("-some-option")
+    val options = defaultOptions
+    // can also use `compileDir` (single test as a dir), `compileFilesInDir` (all tests within a dir)
+    val test = compileFile("tests/pos/tuple-filter.scala", options)
+    // or `RunTestWithCoverage` for "run" tests with output, or `WarnTestWithCoverage` for "warn" tests with warnings
+    type TestKind = PosTestWithCoverage
+    val compilationTest = withCoverage(aggregateTests(test))
+    runWithCoverageOrFallback[TestKind](compilationTest, testGroup.name)
+

compiler/test/dotty/tools/dotc/TastyBootstrapTests.scala

@@ -37,16 +37,16 @@ class TastyBootstrapTests {
     val dotty2Group = TestGroup("tastyBootstrap/dotty2")
 
     // Make sure that the directory is clean
-    dotty.tools.io.Directory(defaultOutputDir + "tastyBootstrap").deleteRecursively()
+    dotty.tools.io.Directory(new java.io.File(defaultOutputDir, "tastyBootstrap").getAbsolutePath).deleteRecursively()
 
     val opt = TestFlags(
       List(
         // compile with bootstrapped library on cp:
-        defaultOutputDir + libGroup + "/lib/",
+        Paths.get(defaultOutputDir.getAbsolutePath, libGroup.name, "lib").toString,
         // and bootstrapped tasty-core:
-        defaultOutputDir + tastyCoreGroup + "/tastyCore/",
+        Paths.get(defaultOutputDir.getAbsolutePath, tastyCoreGroup.name, "tastyCore").toString,
         // as well as bootstrapped compiler:
-        defaultOutputDir + dotty1Group + "/dotty1/",
+        Paths.get(defaultOutputDir.getAbsolutePath, dotty1Group.name, "dotty1").toString,
         // and the other compiler dependencies:
         Properties.compilerInterface, Properties.scalaLibrary, Properties.scalaAsm,
         Properties.dottyInterfaces, Properties.jlineTerminal, Properties.jlineReader,

compiler/test/dotty/tools/dotc/coverage/CoverageTests.scala

@@ -8,15 +8,13 @@ import org.junit.experimental.categories.Category
 import dotty.{BootstrappedOnlyTests, Properties}
 import dotty.tools.vulpix.*
 import dotty.tools.vulpix.TestConfiguration.*
-import dotty.tools.dotc.Main
 import dotty.tools.dotc.reporting.TestReporter
 
 import java.nio.file.{FileSystems, Files, Path, Paths, StandardCopyOption}
 import scala.jdk.CollectionConverters.*
 import scala.util.Properties.userDir
 import scala.language.unsafeNulls
 import scala.collection.mutable.Buffer
-import dotty.tools.dotc.util.DiffUtil
 
 import java.nio.charset.StandardCharsets
 import java.util.stream.Collectors

compiler/test/dotty/tools/dotc/printing/PrintingTest.scala

@@ -26,9 +26,9 @@ import java.io.File
 class PrintingTest {
 
   def options(phase: String, flags: List[String]) =
-    val outDir = ParallelTesting.defaultOutputDir + "printing" + File.pathSeparator
-    File(outDir).mkdirs()
-    List(s"-Vprint:$phase", "-color:never", "-nowarn", "-d", outDir, "-classpath", TestConfiguration.basicClasspath) ::: flags
+    val outDir = new File(ParallelTesting.defaultOutputDir, "printing")
+    outDir.mkdirs()
+    List(s"-Vprint:$phase", "-color:never", "-nowarn", "-d", outDir.getAbsolutePath, "-classpath", TestConfiguration.basicClasspath) ::: flags
 
   private def compileFile(path: JPath, phase: String): Boolean = {
     val baseFilePath  = path.toString.stripSuffix(".scala").stripSuffix(".java")

compiler/test/dotty/tools/vulpix/ParallelTesting.scala

@@ -162,7 +162,7 @@ trait ParallelTesting extends RunnerOrchestration with CoverageSupport:
 
     final override def toString: String = sourceFiles match {
       case Array(f) => f.getPath
-      case _        => outDir.getPath.stripPrefix(defaultOutputDir).stripPrefix(name).stripPrefix("/")
+      case _        => outDir.getPath.stripPrefix(defaultOutputDirName).stripPrefix(name).stripPrefix("/")
     }
   }
 
@@ -507,11 +507,16 @@ trait ParallelTesting extends RunnerOrchestration with CoverageSupport:
       def scalacOptions = toolArgs.getOrElse(ToolName.Scalac, Nil)
       def javacOptions  = toolArgs.getOrElse(ToolName.Javac, Nil)
 
-      val flags = flags0
+      var flags = flags0
         .and(scalacOptions*)
         .and("-d", targetDir.getPath)
         .withClasspath(targetDir.getPath)
 
+      // We must set -sourceroot for SemanticDB extraction to work properly inside an IDE,
+      // but we have many existing coverage tests that assume it is not set, so as a workaround:
+      if !flags.all.contains("-coverage-out") then
+        flags = flags.and("-sourceroot", TestSources.rootPath().toAbsolutePath.toString)
+
       def compileWithJavac(fs: Array[String]) = if (fs.nonEmpty) {
         val fullArgs = Array(
           "-encoding", StandardCharsets.UTF_8.name,
@@ -1409,24 +1414,23 @@ trait ParallelTesting extends RunnerOrchestration with CoverageSupport:
   end CompilationTest
 
   /** Create out directory for directory `d` */
-  def createOutputDirsForDir(d: JFile, sourceDir: JFile, outDir: String): JFile = {
-    val targetDir = new JFile(outDir + s"${sourceDir.getName}/${d.getName}")
+  def createOutputDirsForDir(d: JFile, sourceDir: JFile, outDir: JFile): JFile = {
+    val targetDir = new JFile(outDir, s"${sourceDir.getName}/${d.getName}")
     targetDir.mkdirs()
     targetDir
   }
 
   /** Create out directory for `file` */
-  private def createOutputDirsForFile(file: JFile, sourceDir: JFile, outDir: String): JFile = {
+  private def createOutputDirsForFile(file: JFile, sourceDir: JFile, outDir: JFile): JFile = {
     val uniqueSubdir = file.getName.substring(0, file.getName.lastIndexOf('.'))
-    val targetDir = new JFile(outDir + s"${sourceDir.getName}${JFile.separatorChar}$uniqueSubdir")
+    val targetDir = new JFile(outDir, s"${sourceDir.getName}${JFile.separatorChar}$uniqueSubdir")
     targetDir.mkdirs()
     targetDir
   }
 
   /** Make sure that directory string is as expected */
-  private def checkRequirements(f: String, sourceDir: JFile, outDir: String): Unit = {
+  private def checkRequirements(f: String, sourceDir: JFile, outDir: JFile): Unit = {
     require(sourceDir.isDirectory && sourceDir.exists, "passed non-directory to `compileFilesInDir`: " + sourceDir)
-    require(outDir.last == JFile.separatorChar, "please specify an `outDir` with a trailing file separator")
   }
 
   /** Separates directories from files and returns them as `(dirs, files)` */
@@ -1440,11 +1444,10 @@ trait ParallelTesting extends RunnerOrchestration with CoverageSupport:
 
   /** Compiles a single file from the string path `f` using the supplied flags */
   def compileFile(f: String, flags: TestFlags)(implicit testGroup: TestGroup): CompilationTest = {
-    val sourceFile = new JFile(f)
+    val sourceFile = TestSources.getPath(f).toFile
     val parent = sourceFile.getParentFile
     val outDir =
-      defaultOutputDir + testGroup + JFile.separator +
-      sourceFile.getName.substring(0, sourceFile.getName.lastIndexOf('.')) + JFile.separator
+      new JFile(new JFile(defaultOutputDir, testGroup.name), sourceFile.getName.substring(0, sourceFile.getName.lastIndexOf('.')))
 
     require(
       sourceFile.exists && !sourceFile.isDirectory &&
@@ -1469,8 +1472,8 @@ trait ParallelTesting extends RunnerOrchestration with CoverageSupport:
    *  can be used for randomization.
    */
   def compileDir(f: String, flags: TestFlags, randomOrder: Option[Int] = None, recursive: Boolean = true)(using testGroup: TestGroup): CompilationTest = {
-    val outDir = defaultOutputDir + testGroup + JFile.separator
-    val sourceDir = new JFile(f)
+    val outDir = new JFile(defaultOutputDir, testGroup.name)
+    val sourceDir = TestSources.getPath(f).toFile
     checkRequirements(f, sourceDir, outDir)
 
     def flatten(f: JFile): Array[JFile] =
@@ -1488,7 +1491,7 @@ trait ParallelTesting extends RunnerOrchestration with CoverageSupport:
     }
 
     // Directories in which to compile all containing files with `flags`:
-    val targetDir = new JFile(outDir + JFile.separator + sourceDir.getName + JFile.separator)
+    val targetDir = new JFile(outDir, sourceDir.getName)
     targetDir.mkdirs()
 
     val target = JointCompilationSource(s"compiling '$f' in test '$testGroup'", randomized, flags, targetDir)
@@ -1500,10 +1503,8 @@ trait ParallelTesting extends RunnerOrchestration with CoverageSupport:
    *  dissociated
    */
   def compileList(testName: String, files: List[String], flags: TestFlags)(implicit testGroup: TestGroup): CompilationTest = {
-    val outDir = defaultOutputDir + testGroup + JFile.separator + testName + JFile.separator
-
     // Directories in which to compile all containing files with `flags`:
-    val targetDir = new JFile(outDir)
+    val targetDir = new JFile(new JFile(defaultOutputDir, testGroup.name), testName)
     targetDir.mkdirs()
     assert(targetDir.exists, s"couldn't create target directory: $targetDir")
 
@@ -1531,8 +1532,8 @@ trait ParallelTesting extends RunnerOrchestration with CoverageSupport:
    *    the same name as the directory (with the file extension `.check`)
    */
   def compileFilesInDir(f: String, flags: TestFlags, fileFilter: FileFilter = FileFilter.NoFilter)(implicit testGroup: TestGroup): CompilationTest = {
-    val outDir = defaultOutputDir + testGroup + JFile.separator
-    val sourceDir = new JFile(f)
+    val outDir = new JFile(defaultOutputDir, testGroup.name)
+    val sourceDir = TestSources.getPath(f).toFile
     checkRequirements(f, sourceDir, outDir)
 
     val (dirs, files) = compilationTargets(sourceDir, fileFilter)
@@ -1571,9 +1572,8 @@ trait ParallelTesting extends RunnerOrchestration with CoverageSupport:
    *  Tests in the first part of the tuple must be executed before the second.
    *  Both testsRequires explicit delete().
    */
-  def compileTastyInDir(f: String, flags0: TestFlags, fromTastyFilter: FileFilter)(
-      implicit testGroup: TestGroup): TastyCompilationTest = {
-    val outDir = defaultOutputDir + testGroup + JFile.separator
+  def compileTastyInDir(f: String, flags0: TestFlags, fromTastyFilter: FileFilter)(implicit testGroup: TestGroup): TastyCompilationTest = {
+    val outDir = new JFile(defaultOutputDir, testGroup.name)
     val flags = flags0 `and` "-Yretain-trees"
     val sourceDir = new JFile(f)
     checkRequirements(f, sourceDir, outDir)
@@ -1636,7 +1636,7 @@ trait ParallelTesting extends RunnerOrchestration with CoverageSupport:
     val semanticDbFlag = "-Xsemanticdb"
     assert(!flags.options.contains(bestEffortFlag), "Best effort compilation flag should not be added manually")
 
-    val outDir = defaultOutputDir + testGroup + JFile.separator
+    val outDir = new JFile(defaultOutputDir, testGroup.name)
     val sourceDir = new JFile(f)
     checkRequirements(f, sourceDir, outDir)
 
@@ -1739,7 +1739,7 @@ trait ParallelTesting extends RunnerOrchestration with CoverageSupport:
       val step1SourceFiles = step1SourceDir.listFiles
       val step2SourceFiles = step2SourceDir.listFiles
 
-      val outDir = defaultOutputDir + testGroup + JFile.separator + dir.getName().toString + JFile.separator
+      val outDir = new JFile(new JFile(defaultOutputDir, testGroup.name), dir.getName)
 
       val step1OutDir = createOutputDirsForDir(step1SourceDir, step1SourceDir, outDir)
       val step2OutDir = createOutputDirsForDir(step2SourceDir, step2SourceDir, outDir)
@@ -1825,7 +1825,7 @@ trait ParallelTesting extends RunnerOrchestration with CoverageSupport:
    *  tests.
    */
   def compileShallowFilesInDir(f: String, flags: TestFlags)(implicit testGroup: TestGroup): CompilationTest = {
-    val outDir = defaultOutputDir + testGroup + JFile.separator
+    val outDir = new JFile(defaultOutputDir, testGroup.name)
     val sourceDir = new JFile(f)
     checkRequirements(f, sourceDir, outDir)
 
@@ -1851,7 +1851,8 @@ trait ParallelTesting extends RunnerOrchestration with CoverageSupport:
 
 object ParallelTesting:
 
-  def defaultOutputDir: String = "out"+JFile.separator
+  def defaultOutputDirName: String = "out" + JFile.separator
+  def defaultOutputDir: JFile = TestSources.getPath(defaultOutputDirName).toFile
 
   def isSourceFile(f: JFile): Boolean = {
     val name = f.getName

tests/init-global/special/tastySource/B.check

@@ -5,8 +5,10 @@
   |Reading mutable state of other static objects is forbidden as it breaks initialization-time irrelevance. Calling trace:
   |├── object B:	[ B.scala:1 ]
   |│   ^
-  |├── (no source)	[ tastySource/A.scala:2 ]
-  |├── (no source)	[ tastySource/A.scala:4 ]
+  |├── def foo(fn: => Int) = bar(fn)	[ A.scala:2 ]
+  |│                         ^^^^^^^
+  |├── def bar(fn: => Int) = fn	[ A.scala:4 ]
+  |│                         ^^
   |├── var y = A.foo(bar) * 2	[ B.scala:2 ]
   |│                 ^^^
   |└── def bar = C.n * 3      // warn	[ B.scala:4 ]