src: set ModuleWrap internal fields only once

joyeecheung · richardlau · commit 2c2892bf88f4 · 2024-03-15T17:55:20.000Z
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: #49391 Backport-PR-URL: #51004 Reviewed-By: Darshan Sen <raisinten@gmail.com> Reviewed-By: Yagiz Nizipli <yagiz@nizipli.com> Reviewed-By: Stephen Belanger <admin@stephenbelanger.com> Reviewed-By: Chengzhong Wu <legendecas@gmail.com>
diff --git a/src/module_wrap.cc b/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);
diff --git a/src/module_wrap.h b/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);
