Make root-zone handleUncaughtError rethrow with the correct stack.

sdk/lib/async/zone.dart

Index: sdk/lib/async/zone.dart
diff --git a/sdk/lib/async/zone.dart b/sdk/lib/async/zone.dart
index 225f5d13d69f380f04d66563b18dc573adf1b865..2520f4d73ba9bad0b19be3ce0910deb2269816c9 100644
--- a/sdk/lib/async/zone.dart
+++ b/sdk/lib/async/zone.dart
@@ -891,10 +891,14 @@ class _CustomZone extends _Zone {
 void _rootHandleUncaughtError(
     Zone self, ZoneDelegate parent, Zone zone, error, StackTrace stackTrace) {
   _schedulePriorityAsyncCallback(() {
-    throw new _UncaughtAsyncError(error, stackTrace);
+    if (error == null) error = new NullThrownError();

[turnidge, 2015/10/02 21:00:53]

Use {}'s here and below.

[Lasse Reichstein Nielsen, 2015/10/02 22:50:59]

We don't generally do that (the surrounding code is full of other examples).

[turnidge, 2015/10/02 22:54:35]

Acknowledged.

+    if (stackTrace == null) throw error;
+    _rethrow(error, stackTrace);
   });
 }
 
+external void _rethrow(Object error, StackTrace stackTrace);

[Ivan Posva, 2015/10/02 23:40:39]

Nit: I think it would be better to match the signature of the calling function
which does not have Object as the error being thrown which is more correct in my
opinion.

[Lasse Reichstein Nielsen, 2015/10/05 06:18:49]

I think Object is the right type here - it's accepting any object, and we won't
use it dynamically, so Object is the precise type. 

I also think that the Zone's error object should have been typed as Object, but
I guess that's too late to fix.

+
 dynamic _rootRun(Zone self, ZoneDelegate parent, Zone zone, f()) {
   if (Zone._current == zone) return f();
 
@@ -1009,26 +1013,6 @@ Zone _rootFork(Zone self, ZoneDelegate parent, Zone zone,
   return new _CustomZone(zone, specification, valueMap);
 }
 
-class _RootZoneSpecification implements ZoneSpecification {
-  HandleUncaughtErrorHandler get handleUncaughtError =>
-      _rootHandleUncaughtError;
-  RunHandler get run => _rootRun;
-  RunUnaryHandler get runUnary => _rootRunUnary;
-  RunBinaryHandler get runBinary => _rootRunBinary;
-  RegisterCallbackHandler get registerCallback => _rootRegisterCallback;
-  RegisterUnaryCallbackHandler get registerUnaryCallback =>
-      _rootRegisterUnaryCallback;
-  RegisterBinaryCallbackHandler get registerBinaryCallback =>
-      _rootRegisterBinaryCallback;
-  ErrorCallbackHandler get errorCallback => _rootErrorCallback;
-  ScheduleMicrotaskHandler get scheduleMicrotask => _rootScheduleMicrotask;
-  CreateTimerHandler get createTimer => _rootCreateTimer;
-  CreatePeriodicTimerHandler get createPeriodicTimer =>
-      _rootCreatePeriodicTimer;
-  PrintHandler get print => _rootPrint;
-  ForkHandler get fork => _rootFork;
-}

[turnidge, 2015/10/02 21:00:53]

What's all this about?

[Lasse Reichstein Nielsen, 2015/10/02 22:50:59]

My editor told me the class was unused, so I removed it. Pure clean-up
while-I-was-here.

-
 class _RootZone extends _Zone {
   const _RootZone();