module: defer ESM bootstrap in pre-execution

Author: anonrig

lib/internal/modules/esm/utils.js

@@ -53,7 +53,9 @@ let defaultConditions;
  * @returns {object}
  */
 function getDefaultConditions() {
-  assert(defaultConditions !== undefined);
+  if (defaultConditions === undefined) {
+    initializeDefaultConditions();
+  }
   return defaultConditions;
 }
 
@@ -64,7 +66,9 @@ let defaultConditionsSet;
  * @returns {Set<any>}
  */
 function getDefaultConditionsSet() {
-  assert(defaultConditionsSet !== undefined);
+  if (defaultConditionsSet === undefined) {
+    initializeDefaultConditions();
+  }
   return defaultConditionsSet;
 }
 
@@ -74,18 +78,27 @@ function getDefaultConditionsSet() {
  * @returns {void}
  */
 function initializeDefaultConditions() {
+  if (defaultConditions !== undefined) {
+    return;
+  }
   const userConditions = getOptionValue('--conditions');
   const noAddons = getOptionValue('--no-addons');
-  const addonConditions = noAddons ? [] : ['node-addons'];
-  const moduleConditions = getOptionValue('--require-module') ? ['module-sync'] : [];
-  defaultConditions = ObjectFreeze([
-    'node',
-    'import',
-    ...moduleConditions,
-    ...addonConditions,
-    ...userConditions,
-  ]);
-  defaultConditionsSet = new SafeSet(defaultConditions);
+  const conditions = ['node', 'import'];
+  if (getOptionValue('--require-module')) {
+    conditions[conditions.length] = 'module-sync';
+  }
+  if (!noAddons) {
+    conditions[conditions.length] = 'node-addons';
+  }
+  for (let i = 0; i < userConditions.length; i++) {
+    conditions[conditions.length] = userConditions[i];
+  }
+  defaultConditions = ObjectFreeze(conditions);
+  const set = new SafeSet();
+  for (let i = 0; i < defaultConditions.length; i++) {
+    set.add(defaultConditions[i]);
+  }
+  defaultConditionsSet = set;
 }
 
 /**
@@ -295,12 +308,17 @@ async function importModuleDynamicallyCallback(referrerSymbol, specifier, phase,
 }
 
 let _shouldSpawnLoaderHookWorker = true;
+let esmInitialized = false;
 /**
  * Initializes handling of ES modules.
  * @param {boolean} [shouldSpawnLoaderHookWorker] Whether the custom loader worker
  *   should be spawned later.
  */
 function initializeESM(shouldSpawnLoaderHookWorker = true) {
+  if (esmInitialized) {
+    return;
+  }
+  esmInitialized = true;
   _shouldSpawnLoaderHookWorker = shouldSpawnLoaderHookWorker;
   initializeDefaultConditions();
   // Setup per-realm callbacks that locate data or callbacks that we keep
@@ -391,6 +409,8 @@ module.exports = {
   embedder_module_hdo,
   registerModule,
   initializeESM,
+  initializeImportMetaObject,
+  importModuleDynamicallyCallback,
   getDefaultConditions,
   getConditionsSet,
   shouldSpawnLoaderHookWorker,

lib/internal/process/pre_execution.js

@@ -12,6 +12,7 @@ const {
   NumberParseInt,
   ObjectDefineProperty,
   ObjectFreeze,
+  ReflectApply,
   String,
   globalThis,
 } = primordials;
@@ -217,8 +218,36 @@ function initializeModuleLoaders(options) {
   // Initialize the ESM loader and a few module callbacks.
   // If shouldSpawnLoaderHookWorker is true, later when the ESM loader is instantiated on-demand,
   // it will spawn a loader worker thread to handle async custom loader hooks.
-  const { initializeESM } = require('internal/modules/esm/utils');
-  initializeESM(shouldSpawnLoaderHookWorker);
+  if (!shouldSpawnLoaderHookWorker) {
+    const { initializeESM } = require('internal/modules/esm/utils');
+    initializeESM(shouldSpawnLoaderHookWorker);
+  } else {
+    const {
+      setImportModuleDynamicallyCallback,
+      setInitializeImportMetaObjectCallback,
+    } = internalBinding('module_wrap');
+    let esmInitialized = false;
+    let importModuleDynamicallyCallback;
+    let initializeImportMetaObject;
+    const ensureEsmInitialized = () => {
+      if (esmInitialized) return;
+      const esmUtils = require('internal/modules/esm/utils');
+      esmUtils.initializeESM(shouldSpawnLoaderHookWorker);
+      importModuleDynamicallyCallback = esmUtils.importModuleDynamicallyCallback;
+      initializeImportMetaObject = esmUtils.initializeImportMetaObject;
+      esmInitialized = true;
+    };
+
+    setImportModuleDynamicallyCallback(function() {
+      ensureEsmInitialized();
+      return ReflectApply(importModuleDynamicallyCallback, this, arguments);
+    });
+
+    setInitializeImportMetaObjectCallback(function() {
+      ensureEsmInitialized();
+      return ReflectApply(initializeImportMetaObject, this, arguments);
+    });
+  }
 
   const {
     hasStartedUserCJSExecution,