fs: make mutating options in Promises readdir() not affect results

LiviaMedeiros · marco-ippolito · commit 2c6dcf7209d4 · 2025-01-24T22:18:55.000+01:00
PR-URL: #56057 Reviewed-By: Rafael Gonzaga <rafael.nunu@hotmail.com> Reviewed-By: Luigi Pinca <luigipinca@gmail.com> Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de> Reviewed-By: Juan José Arboleda <soyjuanarbol@gmail.com> Reviewed-By: James M Snell <jasnell@gmail.com>
diff --git a/lib/internal/fs/promises.js b/lib/internal/fs/promises.js
@@ -941,6 +941,10 @@ async function readdirRecursive(originalPath, options) {
 
 async function readdir(path, options) {
   options = getOptions(options);
+
+  // Make shallow copy to prevent mutating options from affecting results
+  options = copyObject(options);
+
   path = getValidatedPath(path);
   if (options.recursive) {
     return readdirRecursive(path, options);
diff --git a/test/parallel/test-fs-readdir-types.js b/test/parallel/test-fs-readdir-types.js
@@ -78,6 +78,14 @@ fs.readdir(readdirDir, {
   assertDirents(dirents);
 })().then(common.mustCall());
 
+// Check that mutating options doesn't affect results
+(async () => {
+  const options = { withFileTypes: true };
+  const direntsPromise = fs.promises.readdir(readdirDir, options);
+  options.withFileTypes = false;
+  assertDirents(await direntsPromise);
+})().then(common.mustCall());
+
 // Check for correct types when the binding returns unknowns
 const UNKNOWN = constants.UV_DIRENT_UNKNOWN;
 const oldReaddir = binding.readdir;
