AbortSignal.any() keeps an AbortSignal.timeout() that has already fired alive forever #66611

Version

v26.10.0 and v26.11.1.

Platform

Linux arm64.

Subsystem

lib (abortcontroller)

What steps will reproduce the bug?

Run node --expose-gc repro.mjs:

// node --expose-gc e2.mjs
const sleep = ms => new Promise(resolve => setTimeout(resolve, ms));
for (const combine of [false, true]) {
  const refs = [];
  let fired = Array.from({ length: 200 }, () => AbortSignal.timeout(1));
  for (const signal of fired) refs.push(new WeakRef(signal));
  await sleep(50);
  if (combine) for (const signal of fired) AbortSignal.any([signal]);
  fired = undefined;
  for (let round = 0; round < 3; round++) { await sleep(10); globalThis.gc(); }
  console.log(`combine=${combine}: ${refs.filter(ref => ref.deref() !== undefined).length}/200 fired timeouts alive`);
}

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

Always. The timeout must have fired before it is passed to AbortSignal.any().

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

combine=true: 1/200 fired timeouts alive, the same as combine=false. A composite of a signal that has already aborted is aborted at once, and nothing is left to wait for, so nothing should keep the timeout alive.

What do you see instead?

combine=true: 200/200 fired timeouts alive: every fired timeout passed to AbortSignal.any() stays reachable after collection.

Additional information

It looks as if the timeout is added to gcPersistentSignals (#57867) and never removed, since it will never fire again. Passing the same fired timeout to new Request(url, { signal }) doesn't keep it alive.