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Buffer is not transferable in Node 21/22Β #55593

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@nex3

Description

Version

v21.7.3, v22.11.0

Platform

Linux nweiz1 6.9.10-1rodete5-amd64 #1 SMP PREEMPT_DYNAMIC Debian 6.9.10-1rodete5 (2024-09-04) x86_64 GNU/Linux

Subsystem

worker_threads

What steps will reproduce the bug?

import {MessageChannel, Worker} from 'worker_threads';

const channel = new MessageChannel();
const buffer = Buffer.from('some text');
channel.port1.postMessage(buffer, [buffer.buffer]);
channel.port2.on('message', (e) => {
  console.log(Buffer.from(e).toString());
  channel.port1.close();
  channel.port2.close();
});

This worked in v20 and fails in v21 and v22.

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

It always reproduces.

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

The buffer should be transferred through the message channel.

What do you see instead?

node:internal/per_context/domexception:53
    ErrorCaptureStackTrace(this);
    ^
DOMException [DataCloneError]: Cannot transfer object of unsupported type.
    at new DOMException (node:internal/per_context/domexception:53:5)
    at file:///.../test.mjs:5:15
    at ModuleJob.run (node:internal/modules/esm/module_job:268:25)
    at async onImport.tracePromise.__proto__ (node:internal/modules/esm/loader:543:26)
    at async asyncRunEntryPointWithESMLoader (node:internal/modules/run_main:116:5)

Node.js v22.11.0

Additional information

I didn't see anything in the v21 or v22 changelogs about buffers becoming untransferable, and transferring it worked in v20, so I'm assuming this is unintentional. If it's intentional, I would have expected at least a deprecation message indicating that this was going to start breaking.

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