util: add getCwdSafe internal util fn

This function was first implemented in #46826, but at some point of the PR implementation this fn was no longer related to the PR. Refs: #46826 (comment) PR-URL: #48434 Backport-PR-URL: #50669 Reviewed-By: Jacob Smith <[email protected]> Reviewed-By: Yagiz Nizipli <[email protected]> Reviewed-By: Antoine du Hamel <[email protected]>

Author: jlenon7

lib/internal/modules/esm/resolve.js

@@ -38,6 +38,7 @@ const experimentalNetworkImports =
 getOptionValue('--experimental-network-imports');
 constinputTypeFlag=getOptionValue('--input-type');
 const{URL, pathToFileURL, fileURLToPath, isURL, toPathIfFileURL }=require('internal/url');
+const{ getCWDURL }=require('internal/util');
 const{canParse: URLCanParse}=internalBinding('url');
 const{
 ERR_INPUT_TYPE_NOT_ALLOWED,
@@ -1175,7 +1176,7 @@ function defaultResolve(specifier, context ={}){
 
 constisMain=parentURL===undefined;
 if(isMain){
-parentURL=pathToFileURL(`${process.cwd()}/`).href;
+parentURL=getCWDURL().href;
 
 // This is the initial entry point to the program, and --input-type has
 // been passed as an option; but --input-type can only be used with

lib/internal/modules/esm/utils.js

@@ -16,7 +16,7 @@ const{
  loadPreloadModules,
  initializeFrozenIntrinsics,
 }=require('internal/process/pre_execution');
-const{pathToFileURL}=require('internal/url');
+const{getCWDURL}=require('internal/util');
 const{
  setImportModuleDynamicallyCallback,
  setInitializeImportMetaObjectCallback,
@@ -146,15 +146,6 @@ function isLoaderWorker(){
 asyncfunctioninitializeHooks(){
 constcustomLoaderURLs=getOptionValue('--experimental-loader');
 
-letcwd;
-try{
-// `process.cwd()` can fail if the parent directory is deleted while the process runs.
-cwd=process.cwd()+'/';
-}catch{
-cwd='/';
-}
-
-
 const{ Hooks }=require('internal/modules/esm/hooks');
 constesmLoader=require('internal/process/esm_loader').esmLoader;
 
@@ -171,7 +162,7 @@ async function initializeHooks(){
 loadPreloadModules();
 initializeFrozenIntrinsics();
 
-constparentURL=pathToFileURL(cwd).href;
+constparentURL=getCWDURL().href;
 for(leti=0;i<customLoaderURLs.length;i++){
 awaithooks.register(
 customLoaderURLs[i],

lib/internal/process/esm_loader.js

@@ -9,8 +9,7 @@ const{getOptionValue } = require('internal/options');
 const{
  hasUncaughtExceptionCaptureCallback,
 }=require('internal/process/execution');
-const{ pathToFileURL }=require('internal/url');
-const{ kEmptyObject }=require('internal/util');
+const{ kEmptyObject, getCWDURL }=require('internal/util');
 
 letesmLoader;
 
@@ -23,14 +22,7 @@ module.exports ={
 try{
 constuserImports=getOptionValue('--import');
 if(userImports.length>0){
-letcwd;
-try{
-// `process.cwd()` can fail if the parent directory is deleted while the process runs.
-cwd=process.cwd()+'/';
-}catch{
-cwd='/';
-}
-constparentURL=pathToFileURL(cwd).href;
+constparentURL=getCWDURL().href;
 awaitSafePromiseAllReturnVoid(userImports,(specifier)=>esmLoader.import(
 specifier,
 parentURL,

lib/internal/util.js

@@ -357,6 +357,36 @@ function getConstructorOf(obj){
 returnnull;
 }
 
+letcachedURL;
+letcachedCWD;
+
+/**
+ * Get the current working directory while accounting for the possibility that it has been deleted.
+ * `process.cwd()` can fail if the parent directory is deleted while the process runs.
+ * @returns{URL} The current working directory or the volume root if it cannot be determined.
+ */
+functiongetCWDURL(){
+const{ sep }=require('path');
+const{ pathToFileURL }=require('internal/url');
+
+letcwd;
+
+try{
+// The implementation of `process.cwd()` already uses proper cache when it can.
+// It's a relatively cheap call performance-wise for the most common use case.
+cwd=process.cwd();
+}catch{
+cachedURL??=pathToFileURL(sep);
+}
+
+if(cwd!=null&&cwd!==cachedCWD){
+cachedURL=pathToFileURL(cwd+sep);
+cachedCWD=cwd;
+}
+
+returncachedURL;
+}
+
 functiongetSystemErrorName(err){
 constentry=uvErrmapGet(err);
 returnentry ? entry[0] : `Unknown system error ${err}`;
@@ -784,6 +814,7 @@ module.exports ={
  filterDuplicateStrings,
  filterOwnProperties,
  getConstructorOf,
+ getCWDURL,
  getInternalGlobal,
  getSystemErrorMap,
  getSystemErrorName,