diff --git a/lib/internal/modules/esm/get_format.js b/lib/internal/modules/esm/get_format.js index ee50bea472758d..1931688e85d05e 100644 --- a/lib/internal/modules/esm/get_format.js +++ b/lib/internal/modules/esm/get_format.js @@ -110,8 +110,10 @@ function getFileProtocolModuleFormat(url, context = { __proto__: null }, ignoreE default: { // The user did not pass `--experimental-default-type`. // `source` is undefined when this is called from `defaultResolve`; // but this gets called again from `defaultLoad`/`defaultLoadSync`. - if (source && getOptionValue('--experimental-detect-module')) { - return containsModuleSyntax(`${source}`, fileURLToPath(url)) ? 'module' : 'commonjs'; + if (getOptionValue('--experimental-detect-module')) { + return source ? + (containsModuleSyntax(`${source}`, fileURLToPath(url)) ? 'module' : 'commonjs') : + null; } return 'commonjs'; } @@ -136,9 +138,13 @@ function getFileProtocolModuleFormat(url, context = { __proto__: null }, ignoreE return 'commonjs'; } default: { // The user did not pass `--experimental-default-type`. - if (source && getOptionValue('--experimental-detect-module') && - getFormatOfExtensionlessFile(url) === 'module') { - return containsModuleSyntax(`${source}`, fileURLToPath(url)) ? 'module' : 'commonjs'; + if (getOptionValue('--experimental-detect-module')) { + if (!source) { return null; } + const format = getFormatOfExtensionlessFile(url); + if (format === 'module') { + return containsModuleSyntax(`${source}`, fileURLToPath(url)) ? 'module' : 'commonjs'; + } + return format; } return 'commonjs'; } diff --git a/lib/internal/modules/esm/load.js b/lib/internal/modules/esm/load.js index f706b5b808da27..6f9b73abd8a761 100644 --- a/lib/internal/modules/esm/load.js +++ b/lib/internal/modules/esm/load.js @@ -105,7 +105,7 @@ function getSourceSync(url, context) { * @param {LoadContext} context * @returns {LoadReturn} */ -async function defaultLoad(url, context = { __proto__: null }) { +async function defaultLoad(url, context = kEmptyObject) { let responseURL = url; let { importAttributes, @@ -129,18 +129,22 @@ async function defaultLoad(url, context = { __proto__: null }) { if (urlInstance.protocol === 'node:') { source = null; - } else if (source == null) { - ({ responseURL, source } = await getSource(urlInstance, context)); - context.source = source; - } + format ??= 'builtin'; + } else { + let contextToPass = context; + if (source == null) { + ({ responseURL, source } = await getSource(urlInstance, context)); + contextToPass = { __proto__: context, source }; + } - if (format == null || format === 'commonjs') { // Now that we have the source for the module, run `defaultGetFormat` again in case we detect ESM syntax. - format = await defaultGetFormat(urlInstance, context); - } + format ??= await defaultGetFormat(urlInstance, contextToPass); - if (format === 'commonjs') { - source = null; // Let the CommonJS loader handle it (for now) + if (format === 'commonjs' && contextToPass !== context) { + // For backward compatibility reasons, we need to discard the source in + // order for the CJS loader to re-fetch it. + source = null; + } } validateAttributes(url, format, importAttributes); diff --git a/test/es-module/test-esm-detect-ambiguous.mjs b/test/es-module/test-esm-detect-ambiguous.mjs index 61629965518a82..34c5f17f007c8f 100644 --- a/test/es-module/test-esm-detect-ambiguous.mjs +++ b/test/es-module/test-esm-detect-ambiguous.mjs @@ -152,6 +152,29 @@ describe('--experimental-detect-module', { concurrency: true }, () => { strictEqual(signal, null); }); } + + it('should not hint wrong format in resolve hook', async () => { + let writeSync; + const { stdout, stderr, code, signal } = await spawnPromisified(process.execPath, [ + '--experimental-detect-module', + '--no-warnings', + '--loader', + `data:text/javascript,import { writeSync } from "node:fs"; export ${encodeURIComponent( + async function resolve(s, c, next) { + const result = await next(s, c); + writeSync(1, result.format + '\n'); + return result; + } + )}`, + fixtures.path('es-modules/package-without-type/noext-esm'), + ]); + + strictEqual(stderr, ''); + strictEqual(stdout, 'null\nexecuted\n'); + strictEqual(code, 0); + strictEqual(signal, null); + + }); }); describe('file input in a "type": "commonjs" package', { concurrency: true }, () => {