module: handle Top-Level Await non-fulfills better

Handle situations in which the main `Promise` from a TLA module
is not fulfilled better:

- When not resolving the `Promise` at all, set a non-zero exit code
  (unless another one has been requested explicitly) to distinguish
  the result from a successful completion.
- When rejecting the `Promise`, always treat it like an uncaught
  exception. In particular, this also ensures a non-zero exit code.

Refs: #34558

PR-URL: #34640
Reviewed-By: James M Snell <[email protected]>
Reviewed-By: Guy Bedford <[email protected]>
Reviewed-By: Myles Borins <[email protected]>
Reviewed-By: Yongsheng Zhang <[email protected]>

Author: addaleax

doc/api/process.md

@@ -2566,6 +2566,8 @@ cases:
   and generally can only happen during development of Node.js itself.
 * `12` **Invalid Debug Argument**: The `--inspect` and/or `--inspect-brk`
   options were set, but the port number chosen was invalid or unavailable.
+* `13` **Unfinished Top-Level Await**: `await` was used outside of a function
+  in the top-level code, but the passed `Promise` never resolved.
 * `>128` **Signal Exits**: If Node.js receives a fatal signal such as
   `SIGKILL` or `SIGHUP`, then its exit code will be `128` plus the
   value of the signal code. This is a standard POSIX practice, since

lib/internal/modules/run_main.js

@@ -40,11 +40,23 @@ function shouldUseESMLoader(mainPath) {
 function runMainESM(mainPath) {
   const esmLoader = require('internal/process/esm_loader');
   const { pathToFileURL } = require('internal/url');
-  esmLoader.loadESM((ESMLoader) => {
+  handleMainPromise(esmLoader.loadESM((ESMLoader) => {
     const main = path.isAbsolute(mainPath) ?
       pathToFileURL(mainPath).href : mainPath;
     return ESMLoader.import(main);
-  });
+  }));
+}
+
+function handleMainPromise(promise) {
+  // Handle a Promise from running code that potentially does Top-Level Await.
+  // In that case, it makes sense to set the exit code to a specific non-zero
+  // value if the main code never finishes running.
+  function handler() {
+    if (process.exitCode === undefined)
+      process.exitCode = 13;
+  }
+  process.on('exit', handler);
+  return promise.finally(() => process.off('exit', handler));
 }
 
 // For backwards compatibility, we have to run a bunch of
@@ -62,5 +74,6 @@ function executeUserEntryPoint(main = process.argv[1]) {
 }
 
 module.exports = {
-  executeUserEntryPoint
+  executeUserEntryPoint,
+  handleMainPromise,
 };

lib/internal/process/execution.js

@@ -2,7 +2,6 @@
 
 const {
   JSONStringify,
-  PromiseResolve,
 } = primordials;
 
 const path = require('path');
@@ -43,20 +42,15 @@ function evalModule(source, print) {
   if (print) {
     throw new ERR_EVAL_ESM_CANNOT_PRINT();
   }
-  const { log, error } = require('internal/console/global');
-  const { decorateErrorStack } = require('internal/util');
-  const asyncESM = require('internal/process/esm_loader');
-  PromiseResolve(asyncESM.ESMLoader).then(async (loader) => {
+  const { log } = require('internal/console/global');
+  const { loadESM } = require('internal/process/esm_loader');
+  const { handleMainPromise } = require('internal/modules/run_main');
+  handleMainPromise(loadESM(async (loader) => {
     const { result } = await loader.eval(source);
     if (print) {
       log(result);
     }
-  })
-  .catch((e) => {
-    decorateErrorStack(e);
-    error(e);
-    process.exit(1);
-  });
+  }));
 }
 
 function evalScript(name, body, breakFirstLine, print) {

test/es-module/test-esm-tla-unfinished.mjs

@@ -0,0 +1,82 @@
+import '../common/index.mjs';
+import assert from 'assert';
+import child_process from 'child_process';
+import fixtures from '../common/fixtures.js';
+
+{
+  // Unresolved TLA promise, --eval
+  const { status, stdout, stderr } = child_process.spawnSync(
+    process.execPath,
+    ['--input-type=module', '--eval', 'await new Promise(() => {})'],
+    { encoding: 'utf8' });
+  assert.deepStrictEqual([status, stdout, stderr], [13, '', '']);
+}
+
+{
+  // Rejected TLA promise, --eval
+  const { status, stdout, stderr } = child_process.spawnSync(
+    process.execPath,
+    ['--input-type=module', '-e', 'await Promise.reject(new Error("Xyz"))'],
+    { encoding: 'utf8' });
+  assert.deepStrictEqual([status, stdout], [1, '']);
+  assert.match(stderr, /Error: Xyz/);
+}
+
+{
+  // Unresolved TLA promise with explicit exit code, --eval
+  const { status, stdout, stderr } = child_process.spawnSync(
+    process.execPath,
+    ['--input-type=module', '--eval',
+     'process.exitCode = 42;await new Promise(() => {})'],
+    { encoding: 'utf8' });
+  assert.deepStrictEqual([status, stdout, stderr], [42, '', '']);
+}
+
+{
+  // Rejected TLA promise with explicit exit code, --eval
+  const { status, stdout, stderr } = child_process.spawnSync(
+    process.execPath,
+    ['--input-type=module', '-e',
+     'process.exitCode = 42;await Promise.reject(new Error("Xyz"))'],
+    { encoding: 'utf8' });
+  assert.deepStrictEqual([status, stdout], [1, '']);
+  assert.match(stderr, /Error: Xyz/);
+}
+
+{
+  // Unresolved TLA promise, module file
+  const { status, stdout, stderr } = child_process.spawnSync(
+    process.execPath,
+    [fixtures.path('es-modules/tla/unresolved.mjs')],
+    { encoding: 'utf8' });
+  assert.deepStrictEqual([status, stdout, stderr], [13, '', '']);
+}
+
+{
+  // Rejected TLA promise, module file
+  const { status, stdout, stderr } = child_process.spawnSync(
+    process.execPath,
+    [fixtures.path('es-modules/tla/rejected.mjs')],
+    { encoding: 'utf8' });
+  assert.deepStrictEqual([status, stdout], [1, '']);
+  assert.match(stderr, /Error: Xyz/);
+}
+
+{
+  // Unresolved TLA promise, module file
+  const { status, stdout, stderr } = child_process.spawnSync(
+    process.execPath,
+    [fixtures.path('es-modules/tla/unresolved-withexitcode.mjs')],
+    { encoding: 'utf8' });
+  assert.deepStrictEqual([status, stdout, stderr], [42, '', '']);
+}
+
+{
+  // Rejected TLA promise, module file
+  const { status, stdout, stderr } = child_process.spawnSync(
+    process.execPath,
+    [fixtures.path('es-modules/tla/rejected-withexitcode.mjs')],
+    { encoding: 'utf8' });
+  assert.deepStrictEqual([status, stdout], [1, '']);
+  assert.match(stderr, /Error: Xyz/);
+}

test/fixtures/es-modules/tla/rejected-withexitcode.mjs

@@ -0,0 +1,2 @@
+process.exitCode = 42;
+await Promise.reject(new Error('Xyz'));

test/fixtures/es-modules/tla/rejected.mjs

@@ -0,0 +1 @@
+await Promise.reject(new Error('Xyz'));

test/fixtures/es-modules/tla/unresolved-withexitcode.mjs

@@ -0,0 +1,2 @@
+process.exitCode = 42;
+await new Promise(() => {});

test/fixtures/es-modules/tla/unresolved.mjs

@@ -0,0 +1 @@
+await new Promise(() => {});