From db125c6ddea16f05b84b284ef21b3b66e67dc3b0 Mon Sep 17 00:00:00 2001
From: Joyee Cheung <joyeec9h3@gmail.com>
Date: Thu, 23 Apr 2026 00:45:47 +0200
Subject: [PATCH] fs: restore fs patchability in ESM loader
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Temporarily restore fs patchability in ESM loader as a workaround
for helping downstream projects that depend on this undocumented
hidden contract transition into using hook proper APIs. This patch
intentionally avoids adding a test and instead adds warning
comments to hopefully steer new code away from depending on it.

PR-URL: https://github.com/nodejs/node/pull/62835
Backport-PR-URL: https://github.com/nodejs/node/pull/64722
Refs: https://github.com/nodejs/node/issues/62012
Reviewed-By: Michaël Zasso <targos@protonmail.com>
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>
Signed-off-by: Ash <92314878+ash2228@users.noreply.github.com>
---
 lib/internal/modules/esm/load.js        | 8 ++++++--
 lib/internal/modules/esm/resolve.js     | 8 ++++++--
 lib/internal/modules/esm/translators.js | 8 ++++++--
 3 files changed, 18 insertions(+), 6 deletions(-)

diff --git a/lib/internal/modules/esm/load.js b/lib/internal/modules/esm/load.js
index 2fc344765d81..f372eef16135 100644
--- a/lib/internal/modules/esm/load.js
+++ b/lib/internal/modules/esm/load.js
@@ -10,7 +10,7 @@ const {
 const { defaultGetFormat } = require('internal/modules/esm/get_format');
 const { validateAttributes, emitImportAssertionWarning } = require('internal/modules/esm/assert');
 const { getOptionValue } = require('internal/options');
-const { readFileSync } = require('fs');
+const fs = require('fs');
 
 const defaultType =
   getOptionValue('--experimental-default-type');
@@ -38,7 +38,11 @@ function getSourceSync(url, context) {
   const responseURL = href;
   let source;
   if (protocol === 'file:') {
-    source = readFileSync(url);
+    // If you are reading this code to figure out how to patch Node.js module loading
+    // behavior - DO NOT depend on the patchability in new code: Node.js
+    // internals may stop going through the JavaScript fs module entirely.
+    // Prefer module.registerHooks() or other more formal fs hooks released in the future.
+    source = fs.readFileSync(url);
   } else if (protocol === 'data:') {
     const result = dataURLProcessor(url);
     if (result === 'failure') {
diff --git a/lib/internal/modules/esm/resolve.js b/lib/internal/modules/esm/resolve.js
index 62b842d61cda..8c917ad60eb8 100644
--- a/lib/internal/modules/esm/resolve.js
+++ b/lib/internal/modules/esm/resolve.js
@@ -25,7 +25,7 @@ const {
 const assert = require('internal/assert');
 const internalFS = require('internal/fs/utils');
 const { BuiltinModule } = require('internal/bootstrap/realm');
-const { realpathSync } = require('fs');
+const fs = require('fs');
 const { getOptionValue } = require('internal/options');
 // Do not eagerly grab .manifest, it may be in TDZ
 const { sep, posix: { relative: relativePosixPath }, resolve } = require('path');
@@ -277,7 +277,11 @@ function finalizeResolution(resolved, base, preserveSymlinks) {
   }
 
   if (!preserveSymlinks) {
-    const real = realpathSync(path, {
+    // If you are reading this code to figure out how to patch Node.js module loading
+    // behavior - DO NOT depend on the patchability in new code: Node.js
+    // internals may stop going through the JavaScript fs module entirely.
+    // Prefer module.registerHooks() or other more formal fs hooks released in the future.
+    const real = fs.realpathSync(path, {
       [internalFS.realpathCacheKey]: realpathCache,
     });
     const { search, hash } = resolved;
diff --git a/lib/internal/modules/esm/translators.js b/lib/internal/modules/esm/translators.js
index a8cb010f470a..8ffe61ce7a0c 100644
--- a/lib/internal/modules/esm/translators.js
+++ b/lib/internal/modules/esm/translators.js
@@ -24,7 +24,7 @@ const {
 
 const { BuiltinModule } = require('internal/bootstrap/realm');
 const assert = require('internal/assert');
-const { readFileSync } = require('fs');
+const fs = require('fs');
 const { dirname, extname } = require('path');
 const {
   assertBufferSource,
@@ -355,7 +355,11 @@ translators.set('commonjs', function commonjsStrategy(url, translateContext, par
 
   try {
     // We still need to read the FS to detect the exports.
-    translateContext.source ??= readFileSync(new URL(url), 'utf8');
+    // If you are reading this code to figure out how to patch Node.js module loading
+    // behavior - DO NOT depend on the patchability in new code: Node.js
+    // internals may stop going through the JavaScript fs module entirely.
+    // Prefer module.registerHooks() or other more formal fs hooks released in the future.
+    translateContext.source ??= fs.readFileSync(new URL(url), 'utf8');
   } catch {
     // Continue regardless of error.
   }