From af32d433eed7f99d0ad8b657850a9dec6e9f681d Mon Sep 17 00:00:00 2001
From: Anna Henningsen <anna@addaleax.net>
Date: Thu, 29 Feb 2024 21:55:00 +0100
Subject: [PATCH] lib: account for cwd access from snapshot serialization cb
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Functions registered with `addSerializeCallback()` can access and call
`process.cwd()`. b7d836e2c7f57 accounted for the fact that it is
necessary to reset the cwd cache after the snapshot builder script has
run, but did not account for possible accesses from serialization
callbacks. To properly account for these, add a deserialization
callback as well.

As a related drive-by fix, also mention the execution order of
callbacks in the documentation.

Refs: https://github.com/nodejs/node/pull/49684
PR-URL: https://github.com/nodejs/node/pull/51901
Reviewed-By: Joyee Cheung <joyeec9h3@gmail.com>
Reviewed-By: Michaël Zasso <targos@protonmail.com>
Reviewed-By: Marco Ippolito <marcoippolito54@gmail.com>
---
 doc/api/v8.md                                             | 4 ++++
 lib/internal/bootstrap/switches/does_own_process_state.js | 6 ++++++
 test/fixtures/snapshot/cwd.js                             | 6 ++++++
 3 files changed, 16 insertions(+)

diff --git a/doc/api/v8.md b/doc/api/v8.md
index 399cb1e82adf12..61ccbd8b9aa0f1 100644
--- a/doc/api/v8.md
+++ b/doc/api/v8.md
@@ -1021,6 +1021,8 @@ get serialized into a snapshot and exit. This can be used to release
 resources that should not or cannot be serialized or to convert user data
 into a form more suitable for serialization.
 
+Callbacks are run in the order in which they are added.
+
 ### `v8.startupSnapshot.addDeserializeCallback(callback[, data])`
 
 <!-- YAML
@@ -1040,6 +1042,8 @@ serialized into the snapshot, they can be used to re-initialize the state
 of the application or to re-acquire resources that the application needs
 when the application is restarted from the snapshot.
 
+Callbacks are run in the order in which they are added.
+
 ### `v8.startupSnapshot.setDeserializeMainFunction(callback[, data])`
 
 <!-- YAML
diff --git a/lib/internal/bootstrap/switches/does_own_process_state.js b/lib/internal/bootstrap/switches/does_own_process_state.js
index 8f457de3e1183e..21c5a0609109b1 100644
--- a/lib/internal/bootstrap/switches/does_own_process_state.js
+++ b/lib/internal/bootstrap/switches/does_own_process_state.js
@@ -4,6 +4,7 @@ const credentials = internalBinding('credentials');
 const rawMethods = internalBinding('process_methods');
 const {
   namespace: {
+    addDeserializeCallback,
     addSerializeCallback,
     isBuildingSnapshot,
   },
@@ -114,8 +115,13 @@ function wrapPosixCredentialSetters(credentials) {
 let cachedCwd = '';
 
 if (isBuildingSnapshot()) {
+  // Reset the cwd on both serialization and deserialization so it's fine
+  // for process.cwd() to be accessed inside of serialization callbacks.
   addSerializeCallback(() => {
     cachedCwd = '';
+    addDeserializeCallback(() => {
+      cachedCwd = '';
+    });
   });
 }
 
diff --git a/test/fixtures/snapshot/cwd.js b/test/fixtures/snapshot/cwd.js
index 4860cc6662af8a..75069d149c17b7 100644
--- a/test/fixtures/snapshot/cwd.js
+++ b/test/fixtures/snapshot/cwd.js
@@ -1,10 +1,16 @@
 const {
+  addSerializeCallback,
   setDeserializeMainFunction,
 } = require('v8').startupSnapshot;
 
 // To make sure the cwd is present in the cache
 process.cwd();
 
+// Also access it from a serialization callback once
+addSerializeCallback(() => {
+  process.cwd();
+});
+
 setDeserializeMainFunction(() => {
   console.log(process.cwd());
 });