improvement for async module runtime

crates/turbopack-ecmascript-runtime/js/src/shared/runtime-utils.ts

@@ -147,11 +147,7 @@ function exportValue(module: Module, value: any) {
 }
 
 function exportNamespace(module: Module, namespace: any) {
-  if (isAsyncModuleExt(module.exports)) {
-    module.exports[turbopackExports] = namespace;
-  } else {
-    module.exports = module.namespaceObject = namespace;
-  }
+  module.exports = module.namespaceObject = namespace;
 }
 
 function createGetter(obj: Record<string | symbol, any>, key: string | symbol) {
@@ -397,21 +393,31 @@ function asyncModule(
 
   const depQueues: Set<AsyncQueue> = new Set();
 
-  ensureDynamicExports(module, module.exports);
-  const exports = module.exports;
-
   const { resolve, reject, promise: rawPromise } = createPromise<Exports>();
 
   const promise: AsyncModulePromise = Object.assign(rawPromise, {
-    [turbopackExports]: exports,
+    [turbopackExports]: module.exports,
     [turbopackQueues]: (fn) => {
       queue && fn(queue);
       depQueues.forEach(fn);
       promise["catch"](() => {});
     },
   } satisfies AsyncModuleExt);
 
-  module.exports = module.namespaceObject = promise;
+  const attributes: PropertyDescriptor = {
+    get(): any {
+      return promise;
+    },
+    set(v: any) {
+      // Calling `esmExport` leads to this.
+      if (v !== promise) {
+        promise[turbopackExports] = v;
+      }
+    },
+  };
+
+  Object.defineProperty(module, "exports", attributes);
+  Object.defineProperty(module, "namespaceObject", attributes);
 
   function handleAsyncDependencies(deps: Dep[]) {
     const currentDeps = wrapDeps(deps);

crates/turbopack-tests/tests/execution.rs

@@ -155,6 +155,12 @@ fn get_messages(js_results: JsResult) -> Vec<String> {
 async fn run(resource: PathBuf, snapshot_mode: IssueSnapshotMode) -> Result<JsResult> {
     register();
 
+    // Clean up old output files.
+    let output_path = resource.join("output");
+    if output_path.exists() {
+        std::fs::remove_dir_all(&output_path)?;
+    }
+
     let tt = TurboTasks::new(MemoryBackend::default());
     tt.run_once(async move {
         let resource_str = resource.to_str().unwrap();