fix(turbopack-ecmascript-runtime): prevent hanging when top level await is skipped (vercel/turborepo#8409)

### Description

A "race condition" was causing the queue to never be resolved.

### Testing Instructions

Added a new test for it


Fixes #65278

Author: ForsakenHarmony

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

@@ -333,12 +333,20 @@ const turbopackQueues = Symbol("turbopack queues");
 const turbopackExports = Symbol("turbopack exports");
 const turbopackError = Symbol("turbopack error");
 
+const enum QueueStatus {
+  Unknown = -1,
+  Unresolved = 0,
+  Resolved = 1,
+}
+
 type AsyncQueueFn = (() => void) & { queueCount: number };
-type AsyncQueue = AsyncQueueFn[] & { resolved: boolean };
+type AsyncQueue = AsyncQueueFn[] & {
+  status: QueueStatus;
+};
 
 function resolveQueue(queue?: AsyncQueue) {
-  if (queue && !queue.resolved) {
-    queue.resolved = true;
+  if (queue && queue.status !== QueueStatus.Resolved) {
+    queue.status = QueueStatus.Resolved;
     queue.forEach((fn) => fn.queueCount--);
     queue.forEach((fn) => (fn.queueCount-- ? fn.queueCount++ : fn()));
   }
@@ -355,11 +363,13 @@ type AsyncModuleExt = {
 type AsyncModulePromise<T = Exports> = Promise<T> & AsyncModuleExt;
 
 function wrapDeps(deps: Dep[]): AsyncModuleExt[] {
-  return deps.map((dep) => {
+  return deps.map((dep): AsyncModuleExt => {
     if (dep !== null && typeof dep === "object") {
       if (isAsyncModuleExt(dep)) return dep;
       if (isPromise(dep)) {
-        const queue: AsyncQueue = Object.assign([], { resolved: false });
+        const queue: AsyncQueue = Object.assign([], {
+          status: QueueStatus.Unresolved,
+        });
 
         const obj: AsyncModuleExt = {
           [turbopackExports]: {},
@@ -381,12 +391,10 @@ function wrapDeps(deps: Dep[]): AsyncModuleExt[] {
       }
     }
 
-    const ret: AsyncModuleExt = {
+    return {
       [turbopackExports]: dep,
       [turbopackQueues]: () => {},
     };
-
-    return ret;
   });
 }
 
@@ -401,7 +409,7 @@ function asyncModule(
   hasAwait: boolean
 ) {
   const queue: AsyncQueue | undefined = hasAwait
-    ? Object.assign([], { resolved: true })
+    ? Object.assign([], { status: QueueStatus.Unknown })
     : undefined;
 
   const depQueues: Set<AsyncQueue> = new Set();
@@ -450,7 +458,7 @@ function asyncModule(
     function fnQueue(q: AsyncQueue) {
       if (q !== queue && !depQueues.has(q)) {
         depQueues.add(q);
-        if (q && !q.resolved) {
+        if (q && q.status === QueueStatus.Unresolved) {
           fn.queueCount++;
           q.push(fn);
         }
@@ -474,8 +482,8 @@ function asyncModule(
 
   body(handleAsyncDependencies, asyncResult);
 
-  if (queue) {
-    queue.resolved = false;
+  if (queue && queue.status === QueueStatus.Unknown) {
+    queue.status = QueueStatus.Unresolved;
   }
 }
 

crates/turbopack-tests/index.d.ts

@@ -1,5 +1,5 @@
-import * as expectMod from "expect";
-import * as jest from "jest-circus";
+import * as expectMod from "./tests/execution/node_modules/expect";
+import * as jest from "./tests/execution/node_modules/jest-circus";
 
 export {};
 

crates/turbopack-tests/tests/execution/turbopack/async-modules/pack-3039-top-level-await/input/index.js

@@ -0,0 +1,6 @@
+it("should not hang", async () => {
+  debugger;
+  const { test } = await import("./wrapper");
+
+  expect(test()).toBe(5);
+}, 1000);

crates/turbopack-tests/tests/execution/turbopack/async-modules/pack-3039-top-level-await/input/repro.js

@@ -0,0 +1,7 @@
+export const x = 5;
+
+const a = 10;
+if (a !== 10) {
+  // intentionally nothing, the skipped await point causes the problem
+  await 0;
+}

crates/turbopack-tests/tests/execution/turbopack/async-modules/pack-3039-top-level-await/input/wrapper.js

@@ -0,0 +1,5 @@
+import { x } from "./repro.js";
+
+export function test() {
+  return x;
+}

crates/turbopack-tests/tests/execution/turbopack/wasm/complex/input/index.js

@@ -1,4 +1,4 @@
-const magicAsyncModule = require("./magic")
+const magicAsyncModule = require("./magic");
 
 describe("complex wasm", () => {
   it("should be possible to use imported memory", async () => {

crates/turbopack-tests/tests/execution/turbopack/wasm/simple/input/math.js

@@ -5,11 +5,11 @@ import { fibonacci } from "./fibonacci.wasm";
 export { add, factorial, fibonacci };
 
 export function factorialJavascript(i) {
-	if (i < 1) return 1;
-	return i * factorialJavascript(i - 1);
+  if (i < 1) return 1;
+  return i * factorialJavascript(i - 1);
 }
 
 export function fibonacciJavascript(i) {
-	if (i < 2) return 1;
-	return fibonacciJavascript(i - 1) + fibonacciJavascript(i - 2);
+  if (i < 2) return 1;
+  return fibonacciJavascript(i - 1) + fibonacciJavascript(i - 2);
 }

crates/turbopack-tests/tests/execution/webpack/async-modules/.reexport-unknown/input/async-unknown.js

@@ -0,0 +1,3 @@
+export * from "./unknown.js";
+
+await 1;

crates/turbopack-tests/tests/execution/webpack/async-modules/.reexport-unknown/input/index.js

@@ -0,0 +1,3 @@
+it("should handle re-export from async modules correctly", async () => {
+  await import("./test.js");
+});

crates/turbopack-tests/tests/execution/webpack/async-modules/.reexport-unknown/input/reexport-async-unknown.js

@@ -0,0 +1,3 @@
+export * from "./async-unknown.js";
+export { a } from "./async-unknown.js";
+export default "default";