René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"AbortSignal.any() keeps an AbortSignal.timeout() that has already fired alive forever","articleBody":"### Version\n\nv26.10.0 and v26.11.1.\n\n### Platform\n\nLinux arm64.\n\n### Subsystem\n\nlib (abortcontroller)\n\n### What steps will reproduce the bug?\n\nRun `node --expose-gc repro.mjs`:\n\n```js\n// node --expose-gc e2.mjs\nconst sleep = ms => new Promise(resolve => setTimeout(resolve, ms));\nfor (const combine of [false, true]) {\n  const refs = [];\n  let fired = Array.from({ length: 200 }, () => AbortSignal.timeout(1));\n  for (const signal of fired) refs.push(new WeakRef(signal));\n  await sleep(50);\n  if (combine) for (const signal of fired) AbortSignal.any([signal]);\n  fired = undefined;\n  for (let round = 0; round \u003c 3; round++) { await sleep(10); globalThis.gc(); }\n  console.log(`combine=${combine}: ${refs.filter(ref => ref.deref() !== undefined).length}/200 fired timeouts alive`);\n}\n```\n\n### How often does it reproduce? Is there a required condition?\n\nAlways. The timeout must have fired before it is passed to `AbortSignal.any()`.\n\n### What is the expected behavior? Why is that the expected behavior?\n\n`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.\n\n### What do you see instead?\n\n`combine=true: 200/200 fired timeouts alive`: every fired timeout passed to `AbortSignal.any()` stays reachable after collection.\n\n### Additional information\n\nIt 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.\n","author":{"url":"https://github.com/rinarakaki","@type":"Person","name":"rinarakaki"},"datePublished":"2026-10-08T17:28:26Z","url":"https://github.com/nodejs/node/issues/66611"}