Errors are not forwarded when using stream.duplexPair()

[skadisch]

Version

v25.2.1

Platform

Linux 6.17.9-arch1-1 #1 SMP PREEMPT_DYNAMIC Mon, 24 Nov 2025 15:21:09 +0000 x86_64 GNU/Linux

Subsystem

stream

What steps will reproduce the bug?

Create a duplex pair and destroy one side with an error.

import stream from "node:stream";

const [ sideA, sideB ] = stream.duplexPair();

sideA.on("error", (err) => {
    console.error("sideA error:", err);
});

sideA.on("close", () => {
    console.log("sideA closed");
});

sideA.resume();

sideB.on("error", (err) => {
    console.error("sideB error:", err);
});

sideB.on("close", () => {
    console.log("sideB closed");
});

sideB.destroy(Error("Simulated error on sideB"));

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

Always

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

I would expect on of the following outputs.

Ideally:

sideB error: Error: Simulated error on sideB
    at file:///duplex-pair-test.ts:23:15
    at ModuleJob.run (node:internal/modules/esm/module_job:413:25)
    at async onImport.tracePromise.__proto__ (node:internal/modules/esm/loader:654:26)
    at async asyncRunEntryPointWithESMLoader (node:internal/modules/run_main:101:5)
sideB closed
sideA error: Error: Simulated error on sideB
    at file:///duplex-pair-test.ts:23:15
    at ModuleJob.run (node:internal/modules/esm/module_job:413:25)
    at async onImport.tracePromise.__proto__ (node:internal/modules/esm/loader:654:26)
    at async asyncRunEntryPointWithESMLoader (node:internal/modules/run_main:101:5)
sideA closed

or

sideB error: Error: Simulated error on sideB
    at file:///duplex-pair-test.ts:23:15
    at ModuleJob.run (node:internal/modules/esm/module_job:413:25)
    at async onImport.tracePromise.__proto__ (node:internal/modules/esm/loader:654:26)
    at async asyncRunEntryPointWithESMLoader (node:internal/modules/run_main:101:5)
sideB closed
sideA closed

The latter would be what I see, if I created a TCP socket pair manually.

What do you see instead?

sideB error: Error: Simulated error on sideB
    at file:///home/simon/projects/krevp/lib/new/duplex-pair-test.ts:23:15
    at ModuleJob.run (node:internal/modules/esm/module_job:413:25)
    at async onImport.tracePromise.__proto__ (node:internal/modules/esm/loader:654:26)
    at async asyncRunEntryPointWithESMLoader (node:internal/modules/run_main:101:5)
sideB closed

sideA doesn't notice that sideB has errored or closed.

Additional information

In the provided minimal example the process also closes, as there are no pending tasks. If I keep it open via e.g. setInterval, still, no events on sideA.

[aelhor]

I can work on this issue