Introduce Debugger

Author: adpi2

compiler/test/dotty/tools/debug/DebugTests.scala

@@ -42,7 +42,10 @@ object DebugTests extends ParallelTesting:
     private def verifyDebug(dir: JFile, testSource: TestSource, warnings: Int, reporters: Seq[TestReporter], logger: LoggedRunnable) =
       if Properties.testsNoRun then addNoRunWarning()
       else
-        val status = debugMain(testSource.runClassPath)(_.launch())
+        val status = debugMain(testSource.runClassPath): debuggee =>
+          val debugger = Debugger(debuggee.jdiPort, maxDuration)
+          try debuggee.launch()
+          finally debugger.dispose()
         status match
           case Success(output) => ()
           case Failure(output) =>

compiler/test/dotty/tools/debug/Debugger.scala

@@ -0,0 +1,25 @@
+package dotty.tools.debug
+
+import com.sun.jdi.*
+import scala.jdk.CollectionConverters.*
+import scala.concurrent.duration.Duration
+
+class Debugger(vm: VirtualMachine, maxDuration: Duration):
+  export vm.dispose
+
+object Debugger:
+  // The socket JDI connector
+  private val connector = Bootstrap.virtualMachineManager
+    .attachingConnectors
+    .asScala
+    .find(_.getClass.getName == "com.sun.tools.jdi.SocketAttachingConnector")
+    .get
+
+  def apply(jdiPort: Int, maxDuration: Duration): Debugger =
+    val arguments = connector.defaultArguments()
+    arguments.get("hostname").setValue("localhost")
+    arguments.get("port").setValue(jdiPort.toString)
+    arguments.get("timeout").setValue(maxDuration.toMillis.toString)
+    val vm = connector.attach(arguments)
+    new Debugger(vm, maxDuration)
+