esm: link modules synchronously when no async loader hooks are used

joyeecheung · richardlau · commit d55c3e7f0bbd · 2025-09-20T04:32:39.000Z
When no async loader hooks are registered, perform the linking as synchronously as possible to reduce the chance of races from the the shared module loading cache. PR-URL: #59519 Fixes: #59366 Refs: https://github.com/abejfehr/node-22.18-issue-repro Reviewed-By: Geoffrey Booth <webadmin@geoffreybooth.com> Reviewed-By: Filip Skokan <panva.ip@gmail.com> Reviewed-By: Chengzhong Wu <legendecas@gmail.com>
diff --git a/lib/internal/modules/esm/loader.js b/lib/internal/modules/esm/loader.js
@@ -63,6 +63,8 @@ let debug = require('internal/util/debuglog').debuglog('esm', (fn) => {
   debug = fn;
 });
 
+const { isPromise } = require('internal/util/types');
+
 /**
  * @typedef {import('./hooks.js').HooksProxy} HooksProxy
  * @typedef {import('./module_job.js').ModuleJobBase} ModuleJobBase
@@ -582,15 +584,21 @@ class ModuleLoader {
 
   /**
    * Load a module and translate it into a ModuleWrap for ordinary imported ESM.
-   * This is run asynchronously.
+   * This may be run asynchronously if there are asynchronous module loader hooks registered.
    * @param {string} url URL of the module to be translated.
    * @param {object} loadContext See {@link load}
    * @param {boolean} isMain Whether the module to be translated is the entry point.
-   * @returns {Promise<ModuleWrap>}
+   * @returns {Promise<ModuleWrap>|ModuleWrap}
    */
-  async loadAndTranslate(url, loadContext, isMain) {
-    const { format, source } = await this.load(url, loadContext);
-    return this.#translate(url, format, source, isMain);
+  loadAndTranslate(url, loadContext, isMain) {
+    const maybePromise = this.load(url, loadContext);
+    const afterLoad = ({ format, source }) => {
+      return this.#translate(url, format, source, isMain);
+    };
+    if (isPromise(maybePromise)) {
+      return maybePromise.then(afterLoad);
+    }
+    return afterLoad(maybePromise);
   }
 
   /**
diff --git a/lib/internal/modules/esm/module_job.js b/lib/internal/modules/esm/module_job.js
@@ -37,6 +37,7 @@ const {
   },
 } = internalBinding('util');
 const { decorateErrorStack, kEmptyObject } = require('internal/util');
+const { isPromise } = require('internal/util/types');
 const {
   getSourceMapsSupport,
 } = require('internal/source_map/source_map_cache');
@@ -135,12 +136,11 @@ class ModuleJob extends ModuleJobBase {
     this.#loader = loader;
 
     // Expose the promise to the ModuleWrap directly for linking below.
-    if (isForRequireInImportedCJS) {
-      this.module = moduleOrModulePromise;
-      assert(this.module instanceof ModuleWrap);
-      this.modulePromise = PromiseResolve(this.module);
-    } else {
+    if (isPromise(moduleOrModulePromise)) {
       this.modulePromise = moduleOrModulePromise;
+    } else {
+      this.module = moduleOrModulePromise;
+      this.modulePromise = PromiseResolve(moduleOrModulePromise);
     }
 
     // Promise for the list of all dependencyJobs.
diff --git a/test/es-module/test-esm-error-cache.js b/test/es-module/test-esm-error-cache.js
@@ -19,7 +19,9 @@ let error;
   await assert.rejects(
     () => import(file),
     (e) => {
-      assert.strictEqual(error, e);
+      // The module may be compiled again and a new SyntaxError would be thrown but
+      // with the same content.
+      assert.deepStrictEqual(error, e);
       return true;
     }
   );
diff --git a/test/es-module/test-esm-import-attributes-errors.js b/test/es-module/test-esm-import-attributes-errors.js
@@ -28,7 +28,7 @@ async function test() {
 
   await rejects(
     import(jsModuleDataUrl, { with: { type: 'json', other: 'unsupported' } }),
-    { code: 'ERR_IMPORT_ATTRIBUTE_TYPE_INCOMPATIBLE' }
+    { code: 'ERR_IMPORT_ATTRIBUTE_UNSUPPORTED' }
   );
 
   await rejects(
@@ -48,7 +48,7 @@ async function test() {
 
   await rejects(
     import(jsonModuleDataUrl, { with: { foo: 'bar' } }),
-    { code: 'ERR_IMPORT_ATTRIBUTE_MISSING' }
+    { code: 'ERR_IMPORT_ATTRIBUTE_UNSUPPORTED' }
   );
 
   await rejects(
diff --git a/test/es-module/test-esm-import-attributes-errors.mjs b/test/es-module/test-esm-import-attributes-errors.mjs
@@ -23,7 +23,7 @@ await rejects(
 
 await rejects(
   import(jsModuleDataUrl, { with: { type: 'json', other: 'unsupported' } }),
-  { code: 'ERR_IMPORT_ATTRIBUTE_TYPE_INCOMPATIBLE' }
+  { code: 'ERR_IMPORT_ATTRIBUTE_UNSUPPORTED' }
 );
 
 await rejects(
@@ -43,7 +43,7 @@ await rejects(
 
 await rejects(
   import(jsonModuleDataUrl, { with: { foo: 'bar' } }),
-  { code: 'ERR_IMPORT_ATTRIBUTE_MISSING' }
+  { code: 'ERR_IMPORT_ATTRIBUTE_UNSUPPORTED' }
 );
 
 await rejects(
