Version

v22.19.0

Platform

Darwin ZG-F3FWLW4DJJ 24.6.0 Darwin Kernel Version 24.6.0: Mon Jul 14 11:28:30 PDT 2025; root:xnu-11417.140.69~1/RELEASE_ARM64_T6030 arm64 

Subsystem

No response

What steps will reproduce the bug?

Node 22.19.0 uses significantly more heap memory than 22.18.0. I think it's because of this change, which introduces a cache for package.json metadata. Some packages are structured in such a way that this cache ends up quite large. The reproduction provided here uses date-fns, which exhibits this clearly.

To reproduce, compare heap snapshots for a script like this:

{ "dependencies": { "date-fns": "^4.1.0" } }

const http = require('node:http'); const { formatISO, } = require('date-fns'); const server = http.createServer((req, res) => { if (req.method === 'GET') { res.writeHead(200); res.write(`${formatISO(new Date())}\n`); res.end(); } }); server.listen(3000);

In my testing, the total heap size for this script on 22.18 is ~7.2 MB, whereas on 22.19 it's ~28.9 MB. This was originally detected in a medium size application where an upgrade to 22.19 ballooned heap usage by more than 50 MB. Inspecting a heap snapshot shows that much of this increase is accounted for by objects retained by nearestParentPackageJSONCache

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

It reproduces consistently on 22.19.0

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

I would not expect such a significant increase in heap usage

What do you see instead?

A significant increase in heap usage

Additional information

A zip containing heap snapshots for the reproduction script is attached

HeapSnapshots.zip