module: fix async resolution error within the sync findPackageJSON

PR-URL: #56382 Reviewed-By: Jordan Harband <ljharb@gmail.com> Reviewed-By: Geoffrey Booth <webadmin@geoffreybooth.com>

Author: JakobJingleheimer

doc/api/module.md

@@ -81,13 +81,17 @@ added: v23.2.0
 * `base` {string|URL} The absolute location (`file:` URL string or FS path) of the
  containing module. For CJS, use `__filename` (not `__dirname`!); for ESM, use
  `import.meta.url`. You do not need to pass it if `specifier` is an `absolute specifier`.
-* Returns: {string|undefined} A path if the `package.json` is found. When `startLocation`
+* Returns: {string|undefined} A path if the `package.json` is found. When `specifier`
  is a package, the package's root `package.json`; when a relative or unresolved, the closest
- `package.json` to the `startLocation`.
+ `package.json` to the `specifier`.
 
-> **Caveat**: Do not use this to try to determine module format. There are many things effecting
+> **Caveat**: Do not use this to try to determine module format. There are many things affecting
 > that determination; the `type` field of package.json is the _least_ definitive (ex file extension
-> superceeds it, and a loader hook superceeds that).
+> supersedes it, and a loader hook supersedes that).
+
+> **Caveat**: This currently leverages only the built-in default resolver; if
+> [`resolve` customization hooks][resolve hook] are registered, they will not affect the resolution.
+> This may change in the future.
 
 ```text
 /path/to/project

lib/internal/modules/package_json_reader.js

@@ -267,8 +267,8 @@ function getPackageJSONURL(specifier, base) {
  throw new ERR_MODULE_NOT_FOUND(packageName, fileURLToPath(base), null);
 }
 
-const pjsonImportAttributes = { __proto__: null, type: 'json' };
-let cascadedLoader;
+/** @type {import('./esm/resolve.js').defaultResolve} */
+let defaultResolve;
 /**
  * @param {URL['href'] | string | URL} specifier The location for which to get the "root" package.json
  * @param {URL['href'] | string | URL} [base] The location of the current module (ex file://tmp/foo.js).
@@ -296,10 +296,15 @@ function findPackageJSON(specifier, base = 'data:') {
  }
 
  let resolvedTarget;
- cascadedLoader ??= require('internal/modules/esm/loader').getOrInitializeCascadedLoader();
+ defaultResolve ??= require('internal/modules/esm/resolve').defaultResolve;
 
  try {
- resolvedTarget = cascadedLoader.resolve(specifier, `${parentURL}`, pjsonImportAttributes).url;
+ // TODO(@JakobJingleheimer): Detect whether findPackageJSON is being used within a loader
+ // (possibly piggyback on `allowImportMetaResolve`)
+ // - When inside, use the default resolve
+ // - (I think it's impossible to use the chain because of re-entry & a deadlock from atomics).
+ // - When outside, use cascadedLoader.resolveSync (not implemented yet, but the pieces exist).
+ resolvedTarget = defaultResolve(specifier, { parentURL: `${parentURL}` }).url;
  } catch (err) {
  if (err.code === 'ERR_UNSUPPORTED_DIR_IMPORT') {
  resolvedTarget = err.url;

test/parallel/test-find-package-json.js

@@ -149,4 +149,44 @@ describe('findPackageJSON', () => { // Throws when no arguments are provided
  });
  }));
  });
+
+ it('should work within a loader', async () => {
+ const specifierBase = './packages/root-types-field';
+ const target = fixtures.fileURL(specifierBase, 'index.js');
+ const foundPjsonPath = path.toNamespacedPath(fixtures.path(specifierBase, 'package.json'));
+ const { code, stderr, stdout } = await common.spawnPromisified(process.execPath, [
+ '--no-warnings',
+ '--loader',
+ [
+ 'data:text/javascript,',
+ 'import fs from "node:fs";',
+ 'import module from "node:module";',
+ encodeURIComponent(`fs.writeSync(1, module.findPackageJSON(${JSON.stringify(target)}));`),
+ 'export const resolve = async (s, c, n) => n(s);',
+ ].join(''),
+ '--eval',
+ 'import "node:os";', // Can be anything that triggers the resolve hook chain
+ ]);
+
+ assert.strictEqual(stderr, '');
+ assert.ok(stdout.includes(foundPjsonPath), stdout);
+ assert.strictEqual(code, 0);
+ });
+
+ it('should work with an async resolve hook registered', async () => {
+ const specifierBase = './packages/root-types-field';
+ const target = fixtures.fileURL(specifierBase, 'index.js');
+ const foundPjsonPath = path.toNamespacedPath(fixtures.path(specifierBase, 'package.json'));
+ const { code, stderr, stdout } = await common.spawnPromisified(process.execPath, [
+ '--no-warnings',
+ '--loader',
+ 'data:text/javascript,export const resolve = async (s, c, n) => n(s);',
+ '--print',
+ `require("node:module").findPackageJSON(${JSON.stringify(target)})`,
+ ]);
+
+ assert.strictEqual(stderr, '');
+ assert.ok(stdout.includes(foundPjsonPath), stdout);
+ assert.strictEqual(code, 0);
+ });
 });