Fix for issue 28606 - Wait for thread that runs the interrupted isolate to exit completely before e…

runtime/vm/debugger_api_impl_test.cc

Index: runtime/vm/debugger_api_impl_test.cc
diff --git a/runtime/vm/debugger_api_impl_test.cc b/runtime/vm/debugger_api_impl_test.cc
index beb26e467b270b470d7b8116732727c5de4ef278..ee47df91c54befe28139ed51089bfc845238bc61 100644
--- a/runtime/vm/debugger_api_impl_test.cc
+++ b/runtime/vm/debugger_api_impl_test.cc
@@ -1446,6 +1446,7 @@ VM_UNIT_TEST_CASE(Debug_IsolateID) {
 static Monitor* sync = NULL;
 static bool isolate_interrupted = false;
 static bool pause_event_handled = false;
+static bool interrupt_thread_stopped = false;
 static Dart_IsolateId interrupt_isolate_id = ILLEGAL_ISOLATE_ID;
 static volatile bool continue_isolate_loop = true;
 
@@ -1533,6 +1534,12 @@ static void InterruptIsolateRun(uword unused) {
   EXPECT_VALID(retval);
   Dart_ExitScope();
   Dart_ShutdownIsolate();
+  {
+    // Notify the waiting thread that we are done.
+    MonitorLocker ml(sync);
+    interrupt_thread_stopped = true;
+    ml.Notify();
+  }
 }
 
 
@@ -1543,6 +1550,10 @@ TEST_CASE(Debug_InterruptIsolate) {
   Dart_SetIsolateEventHandler(&TestInterruptIsolate);
   EXPECT(interrupt_isolate_id == ILLEGAL_ISOLATE_ID);
   Dart_SetPausedEventHandler(InterruptIsolateHandler);
+  {
+    MonitorLocker ml(sync);
+    interrupt_thread_stopped = false;
+  }
   int result = OSThread::Start("DebugInterruptIsolate", InterruptIsolateRun, 0);
   EXPECT_EQ(0, result);
 
@@ -1580,6 +1591,17 @@ TEST_CASE(Debug_InterruptIsolate) {
     }
   }
   EXPECT(interrupt_isolate_id == ILLEGAL_ISOLATE_ID);
+
+  // Wait for the OSThread that we started above, if we do
+  // not wait we end up with a race between the process
+  // exiting and cleaning up while the thread above is cleaning
+  // up stuff from the isolate leading to flaky crashes.
+  {
+    MonitorLocker ml(sync);
+    while (!interrupt_thread_stopped) {
+      ml.Wait();
+    }
+  }
   OS::PrintErr("Complete\n");
   FLAG_trace_shutdown = saved_flag;
 }