Attempt to log the stack where cross-request promises are being resolved

src/workerd/io/worker.c++

@@ -1194,6 +1194,20 @@ Worker::Isolate::Isolate(kj::Own<Api> apiParam,
                   v8::Local<v8::Value> argument)> callback) -> v8::Maybe<void> {
         try {
           auto& js = jsg::Lock::from(isolate);
+
+          {
+            // TODO(soon): Hopefully this logging is temporary. We want to get an idea
+            // of where the cross request promises are being resolved just in general.
+            // To do so we need to try to capture a stack. We do so by creating an error
+            // object and logging it.
+            v8::HandleScope handleScope(isolate);
+            auto err = v8::Exception::Error(js.str(""_kj)).As<v8::Object>();
+            jsg::check(err->Set(
+                js.v8Context(), js.str("name"_kj), js.str("Cross Request Promise Resolve"_kj)));
+            auto stack = jsg::check(err->Get(js.v8Context(), js.str("stack"_kj)));
+            KJ_LOG(WARNING, kj::str("NOSENTRY ", stack));
+          }
+
           // The promise tag is generally opaque except for right here. The tag
           // wraps an instanceof kj::Own<IoCrossContextExecutor>, which wraps an atomically
           // refcounted pointer to the DeleteQueue for the correct isolate.