Trigger debug event on not yet caught exception in promises.

src/runtime.cc

Index: src/runtime.cc
diff --git a/src/runtime.cc b/src/runtime.cc
index c508b4a644fb2540caf3c178d11af3ab7841a057..7fffa3275fc452e6e86a4cc28678f79c69867ce9 100644
--- a/src/runtime.cc
+++ b/src/runtime.cc
@@ -5649,6 +5649,20 @@ RUNTIME_FUNCTION(Runtime_DebugPrepareStepInIfStepping) {
 }
 
 
+// Notify the debugger if an expcetion in a promise is not caught (yet).
+RUNTIME_FUNCTION(Runtime_DebugPendingExceptionInPromise) {
+  SealHandleScope shs(isolate);
+#ifdef ENABLE_DEBUGGER_SUPPORT
+  ASSERT(args.length() == 2);
+  HandleScope scope(isolate);

[rossberg, 2014/04/24 07:27:36]

Why have both a SHS and a HS in the same function?

[rossberg, 2014/04/24 08:08:38]

Seems like you missed this one.

+  CONVERT_ARG_HANDLE_CHECKED(Object, exception, 0);
+  CONVERT_ARG_HANDLE_CHECKED(Object, deferred_promise, 1);

[rossberg, 2014/04/24 07:27:36]

One more.

[Yang, 2014/04/24 10:42:04]

Done.

+  isolate->debugger()->OnException(exception, false, deferred_promise);

[yurys, 2014/04/24 07:48:43]

It might make sense to report the exception as uncaught=true here in case there
is no catch handler on the promise yet.

[Yang, 2014/04/24 07:59:59]

Done.

Alternatively, we could always fire this runtime function, and set uncaught
depending on whether we already have a catch handler. Devtools would then filter
out caught ones. That would give you guys more flexibility (not sure if
necessary).

[yurys, 2014/04/24 08:49:50]

I believe this is not necessary. We have three modes in DevTools:
1) don't pause on exception
2) pause on uncaught exceptions only (controlled by
Debug.setBreakOnUncaughtException();)
3) pause on all exceptions (controlled by  Debug.setBreakOnException();)
All of them are handled in v8 at the moment and I believe the promises should
follow that logic too.

+#endif  // ENABLE_DEBUGGER_SUPPORT
+  return isolate->heap()->undefined_value();
+}
+
+
 // Set a local property, even if it is READ_ONLY.  If the property does not
 // exist, it will be added with attributes NONE.
 RUNTIME_FUNCTION(Runtime_IgnoreAttributesAndSetProperty) {