fs: incorrect handling of numeric times from before the unix epoch

Version

v22.16.0

Platform

Linux johnp-pc 7.1.3-200.fc44.x86_64 #1 SMP PREEMPT_DYNAMIC Sat Jul  4 19:20:12 UTC 2026 x86_64 GNU/Linux

Subsystem

node:fs

What steps will reproduce the bug?

Description

Since https://github.com/nodejs/node/commit/1f842c2c613545ba69ad5b9ab48c49ac1f77d8d3, NodeJS internally modifies numeric negative utimes to the current time. This is unexpected, as negative strings ("-1") work as expected. This issue was previously reported, but not all possible types (date, string, number) were considered. and the bug therefore wrongly closed.

Reproducer

import fs from 'node:fs';

const file = 'neg_timespec.txt';
fs.writeFileSync(file, 'test');

// Set time to -1 second before 1970
fs.utimesSync(file, -1, -1);

const stats = fs.statSync(file);
console.log("Expected mtime (ms): -1000");
console.log("Actual mtime (ms):  ", stats.mtime.getTime());

fs.unlinkSync(file);

Incorrect code

https://github.com/nodejs/node/blob/4f844f4380a143d0c24b39d1df34b187b06619ae/lib/internal/fs/utils.js#L783-L793

How often does it reproduce? Is there a required condition?

100%

What is the expected behavior? Why is that the expected behavior?

Expected mtime (ms): -1500

What do you see instead?

Actual mtime (ms): 1784465433024

Additional information

Found investigating the Rust port of Bun, where the bug was copied by AI presumably.

Start by running the provided JavaScript reproducer, then inspect lib/internal/fs/utils.js at the linked lines. Trace how numeric negative utimes values are handled and verify the expected pre-Unix-epoch timestamp, resolving the issue’s -1000 versus -1500 wording. Done means numeric negative times no longer become the current time.