Report promise reject with no handler (behind a flag).

src/runtime/runtime.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include <stdlib.h>
 #include <limits>
 
 #include "src/v8.h"
 
 #include "src/accessors.h"
@@ skipping 5323 matching lines @@
 
 RUNTIME_FUNCTION(Runtime_DebugPromiseEvent) {
   DCHECK(args.length() == 1);
   HandleScope scope(isolate);
   CONVERT_ARG_HANDLE_CHECKED(JSObject, data, 0);
   isolate->debug()->OnPromiseEvent(data);
   return isolate->heap()->undefined_value();
 }
 
 
-RUNTIME_FUNCTION(Runtime_DebugPromiseRejectEvent) {
+RUNTIME_FUNCTION(Runtime_PromiseRejectEvent) {
   DCHECK(args.length() == 2);
   HandleScope scope(isolate);
   CONVERT_ARG_HANDLE_CHECKED(JSObject, promise, 0);
   CONVERT_ARG_HANDLE_CHECKED(Object, value, 1);
-  isolate->debug()->OnPromiseReject(promise, value);
+  // Check whether the promise has been marked as having triggered a message.
+  Handle<Symbol> key = isolate->factory()->promise_debug_symbol();
+  Maybe<bool> marked = JSObject::HasOwnProperty(promise, key);
+  DCHECK(marked.has_value);
+  if (!marked.value) {
+    isolate->debug()->OnPromiseReject(promise, value);
+    isolate->ReportPromiseReject(promise, value, NULL);
+  }
   return isolate->heap()->undefined_value();
 }
 
 
 RUNTIME_FUNCTION(Runtime_DebugAsyncTaskEvent) {
   DCHECK(args.length() == 1);
   HandleScope scope(isolate);
   CONVERT_ARG_HANDLE_CHECKED(JSObject, data, 0);
   isolate->debug()->OnAsyncTaskEvent(data);
   return isolate->heap()->undefined_value();
@@ skipping 9212 matching lines @@
   }
   return NULL;
 }
 
 
 const Runtime::Function* Runtime::FunctionForId(Runtime::FunctionId id) {
   return &(kIntrinsicFunctions[static_cast<int>(id)]);
 }
 }
 }  // namespace v8::internal