node/lib/internal/modules/run_main.js
Anna Henningsen e948ef351b
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: https://github.com/nodejs/node/pull/34558

PR-URL: https://github.com/nodejs/node/pull/34640
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Guy Bedford <guybedford@gmail.com>
Reviewed-By: Myles Borins <myles.borins@gmail.com>
Reviewed-By: Yongsheng Zhang <zyszys98@gmail.com>
2020-08-08 20:33:46 +02:00

80 lines
2.5 KiB
JavaScript

'use strict';
const CJSLoader = require('internal/modules/cjs/loader');
const { Module, toRealPath, readPackageScope } = CJSLoader;
const { getOptionValue } = require('internal/options');
const path = require('path');
function resolveMainPath(main) {
// Note extension resolution for the main entry point can be deprecated in a
// future major.
// Module._findPath is monkey-patchable here.
let mainPath = Module._findPath(path.resolve(main), null, true);
if (!mainPath)
return;
const preserveSymlinksMain = getOptionValue('--preserve-symlinks-main');
if (!preserveSymlinksMain)
mainPath = toRealPath(mainPath);
return mainPath;
}
function shouldUseESMLoader(mainPath) {
const userLoader = getOptionValue('--experimental-loader');
if (userLoader)
return true;
const esModuleSpecifierResolution =
getOptionValue('--es-module-specifier-resolution');
if (esModuleSpecifierResolution === 'node')
return true;
// Determine the module format of the main
if (mainPath && mainPath.endsWith('.mjs'))
return true;
if (!mainPath || mainPath.endsWith('.cjs'))
return false;
const pkg = readPackageScope(mainPath);
return pkg && pkg.data.type === 'module';
}
function runMainESM(mainPath) {
const esmLoader = require('internal/process/esm_loader');
const { pathToFileURL } = require('internal/url');
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
// monkey-patchable code that belongs to the CJS loader (exposed by
// `require('module')`) even when the entry point is ESM.
function executeUserEntryPoint(main = process.argv[1]) {
const resolvedMain = resolveMainPath(main);
const useESMLoader = shouldUseESMLoader(resolvedMain);
if (useESMLoader) {
runMainESM(resolvedMain || main);
} else {
// Module._load is the monkey-patchable CJS module loader.
Module._load(main, null, true);
}
}
module.exports = {
executeUserEntryPoint,
handleMainPromise,
};