Fix bug 1529: check for NULL handle in v8::TryCatch::StackTrace.

src/api.cc

 // Copyright 2011 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 1664 matching lines @@
 
 v8::Local<Value> v8::TryCatch::StackTrace() const {
   ASSERT(isolate_ == i::Isolate::Current());
   if (HasCaught()) {
     i::Object* raw_obj = reinterpret_cast<i::Object*>(exception_);
     if (!raw_obj->IsJSObject()) return v8::Local<Value>();
     i::HandleScope scope(isolate_);
     i::Handle<i::JSObject> obj(i::JSObject::cast(raw_obj), isolate_);
     i::Handle<i::String> name = isolate_->factory()->LookupAsciiSymbol("stack");
     if (!obj->HasProperty(*name)) return v8::Local<Value>();
-    return v8::Utils::ToLocal(scope.CloseAndEscape(i::GetProperty(obj, name)));
+    i::Handle<i::Object> value = i::GetProperty(obj, name);
+    if (value.is_null()) return v8::Local<Value>();
+    return v8::Utils::ToLocal(scope.CloseAndEscape(value));
   } else {
     return v8::Local<Value>();
   }
 }
 
 
 v8::Local<v8::Message> v8::TryCatch::Message() const {
   ASSERT(isolate_ == i::Isolate::Current());
   if (HasCaught() && message_ != i::Smi::FromInt(0)) {
     i::Object* message = reinterpret_cast<i::Object*>(message_);
@@ skipping 4400 matching lines @@
 
 
 char* HandleScopeImplementer::Iterate(ObjectVisitor* v, char* storage) {
   HandleScopeImplementer* scope_implementer =
       reinterpret_cast<HandleScopeImplementer*>(storage);
   scope_implementer->IterateThis(v);
   return storage + ArchiveSpacePerThread();
 }
 
 } }  // namespace v8::internal