src: set ModuleWrap internal fields only once

There is no need to initialize the internal fields to undefined
and then initialize them to something else in the caller. Simply
pass the internal fields into the constructor to initialize
them just once.

PR-URL: nodejs#49391
Reviewed-By: Darshan Sen <[email protected]>
Reviewed-By: Yagiz Nizipli <[email protected]>
Reviewed-By: Stephen Belanger <[email protected]>
Reviewed-By: Chengzhong Wu <[email protected]>

Author: joyeecheung

src/module_wrap.cc

@@ -52,16 +52,22 @@ using v8::Value;
 ModuleWrap::ModuleWrap(Environment* env,
                        Local<Object> object,
                        Local<Module> module,
-                       Local<String> url)
-  : BaseObject(env, object),
-    module_(env->isolate(), module),
-    id_(env->get_next_module_id()) {
+                       Local<String> url,
+                       Local<Object> context_object,
+                       Local<Value> synthetic_evaluation_step)
+    : BaseObject(env, object),
+      module_(env->isolate(), module),
+      id_(env->get_next_module_id()) {
   env->id_to_module_map.emplace(id_, this);
 
-  Local<Value> undefined = Undefined(env->isolate());
   object->SetInternalField(kURLSlot, url);
-  object->SetInternalField(kSyntheticEvaluationStepsSlot, undefined);
-  object->SetInternalField(kContextObjectSlot, undefined);
+  object->SetInternalField(kSyntheticEvaluationStepsSlot,
+                           synthetic_evaluation_step);
+  object->SetInternalField(kContextObjectSlot, context_object);
+
+  if (!synthetic_evaluation_step->IsUndefined()) {
+    synthetic_ = true;
+  }
 }
 
 ModuleWrap::~ModuleWrap() {
@@ -79,7 +85,9 @@ ModuleWrap::~ModuleWrap() {
 
 Local<Context> ModuleWrap::context() const {
   Local<Value> obj = object()->GetInternalField(kContextObjectSlot).As<Value>();
-  if (obj.IsEmpty()) return {};
+  // If this fails, there is likely a bug e.g. ModuleWrap::context() is accessed
+  // before the ModuleWrap constructor completes.
+  CHECK(obj->IsObject());
   return obj.As<Object>()->GetCreationContext().ToLocalChecked();
 }
 
@@ -227,18 +235,16 @@ void ModuleWrap::New(const FunctionCallbackInfo<Value>& args) {
     return;
   }
 
-  ModuleWrap* obj = new ModuleWrap(env, that, module, url);
-
-  if (synthetic) {
-    obj->synthetic_ = true;
-    obj->object()->SetInternalField(kSyntheticEvaluationStepsSlot, args[3]);
-  }
-
   // Use the extras object as an object whose GetCreationContext() will be the
   // original `context`, since the `Context` itself strictly speaking cannot
   // be stored in an internal field.
-  obj->object()->SetInternalField(kContextObjectSlot,
-      context->GetExtrasBindingObject());
+  Local<Object> context_object = context->GetExtrasBindingObject();
+  Local<Value> synthetic_evaluation_step =
+      synthetic ? args[3] : Undefined(env->isolate()).As<v8::Value>();
+
+  ModuleWrap* obj = new ModuleWrap(
+      env, that, module, url, context_object, synthetic_evaluation_step);
+
   obj->contextify_context_ = contextify_context;
 
   env->hash_to_module_map.emplace(module->GetIdentityHash(), obj);

src/module_wrap.h

@@ -72,7 +72,9 @@ class ModuleWrap : public BaseObject {
   ModuleWrap(Environment* env,
              v8::Local<v8::Object> object,
              v8::Local<v8::Module> module,
-             v8::Local<v8::String> url);
+             v8::Local<v8::String> url,
+             v8::Local<v8::Object> context_object,
+             v8::Local<v8::Value> synthetic_evaluation_step);
   ~ModuleWrap() override;
 
   static void New(const v8::FunctionCallbackInfo<v8::Value>& args);