Avoid to run dart code during paused_on_exit

runtime/observatory/tests/service/issue_30555_test.dart

Index: runtime/observatory/tests/service/issue_30555_test.dart
diff --git a/runtime/observatory/tests/service/issue_30555_test.dart b/runtime/observatory/tests/service/issue_30555_test.dart
new file mode 100644
index 0000000000000000000000000000000000000000..2e5d5069b1e1dffb37846d15c093d4d77254c45a
--- /dev/null
+++ b/runtime/observatory/tests/service/issue_30555_test.dart
@@ -0,0 +1,65 @@
+// Copyright (c) 2015, the Dart project authors.  Please see the AUTHORS file

[siva, 2017/08/28 23:11:31]

2017

[cbernaschina, 2017/08/28 23:21:27]

Done.

+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+// VMOptions=--error_on_bad_type --error_on_bad_override
+
+import 'dart:async';
+import 'dart:developer';
+import 'package:observatory/service_io.dart';
+import 'package:unittest/unittest.dart';
+import 'test_helper.dart';
+
+import "dart:isolate" as dart;
+
+void isolate(dart.SendPort port) {
+  dart.RawReceivePort receive = new dart.RawReceivePort((_) {
+    debugger();
+  });
+  port.send(receive.sendPort);

[siva, 2017/08/28 23:11:31]

Maybe move the port send to inside the timer to make sure there are no timing
related issues which makes it possible for the "port.send(null)" command to
succeed.

[cbernaschina, 2017/08/28 23:21:27]

The final logic is changed

+  new Timer.periodic(const Duration(milliseconds: 1), (_) {
+    throw new Exception();
+  });
+}
+
+void test() {
+  dart.RawReceivePort receive = new dart.RawReceivePort((port) {
+    port;

[siva, 2017/08/28 23:11:31]

Maybe remove this line as discussed offline.

[cbernaschina, 2017/08/28 23:21:27]

Done.

+    debugger();
+  });
+  dart.Isolate.spawn(isolate, receive.sendPort);
+}
+
+var tests = [
+  (VM vm) async {
+    await vm.load();
+    int step = 0;
+    var sub = await vm.listenEventStream("Debug", (c) {
+      print(c);
+      switch (step) {
+        case 0: //Resume
+          break;
+        case 1: //PauseOnStart
+          vm.isolates[1].resume();
+          break;
+        case 2: //Resume
+          break;
+        case 3: //Debugger
+          vm.isolates[0]
+              .evalFrame(vm.isolates[0].topFrame.index, "port.send(null);");
+          break;
+        case 4: //PauseOnExit
+          break;
+        case 5:
+          expect(false, isTrue);
+          break;
+      }

[siva, 2017/08/28 23:11:31]

As discussed offline maybe make these events recorded in the debugger more
explicit instead of relying on the step number, dues to timing issues some of
the events may come out of sequence causing the test to fail or get into a weird
state.

[cbernaschina, 2017/08/28 23:21:27]

Done.

+      step++;
+    });
+    vm.isolates[0].resume();
+    await new Future.delayed(const Duration(seconds: 2));
+    sub.cancel();
+  }
+];
+
+main(args) async => runVMTests(args, tests,
+    pause_on_start: true, pause_on_exit: true, testeeConcurrent: test);