René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"stream/iter: pending next() hangs after iterator return()","articleBody":"### Version\n\n26.2.0\n\n### Platform\n\n```text\nmacOS 26.5.0\n```\n\n### Subsystem\n\nstream\n\n### What steps will reproduce the bug?\n\n```js\nimport { broadcast, push } from 'node:stream/iter';\n\nasync function check(name, pendingNext) {\n  const result = await Promise.race([\n    pendingNext.then(\n      (value) =\u003e ({ status: 'settled', value }),\n      (error) =\u003e ({ status: 'rejected', error }),\n    ),\n    new Promise((resolve) =\u003e {\n      setTimeout(() =\u003e resolve({ status: 'timeout' }), 100);\n    }),\n  ]);\n\n  if (result.status === 'timeout') {\n    console.log(`${name}: observed hang; expected pending next() to settle after return()`);\n  } else {\n    console.log(`${name}: settled`, result);\n  }\n}\n\n{\n  const { readable } = push();\n  const iter = readable[Symbol.asyncIterator]();\n\n  const pendingNext = iter.next();\n  await iter.return();\n\n  await check('push()', pendingNext);\n}\n\n{\n  const { broadcast: bc } = broadcast();\n  const iter = bc.push()[Symbol.asyncIterator]();\n\n  const pendingNext = iter.next();\n  await iter.return();\n\n  await check('broadcast()', pendingNext);\n}\n```\n\n### How often does it reproduce? Is there a required condition?\n\nAlways\n\n### What is the expected behavior? Why is that the expected behavior?\n\n```console\npush(): settled {\n  status: 'settled',\n  value: [Object: null prototype] { value: undefined, done: true }\n}\nbroadcast(): settled {\n  status: 'settled',\n  value: [Object: null prototype] { done: true, value: undefined }\n}\n```\n\n`pendingNext` should settle after await `iter.return()`, normally as `{ value: undefined, done: true }` or a rejection, so no read promise is left unresolved.\n\n### What do you see instead?\n\n```console\npush(): observed hang; expected pending next() to settle after return()\nbroadcast(): observed hang; expected pending next() to settle after return()\n```\n\n`pendingNext` stays pending and the timeout wins, because `next()` stores a resolver for the empty read, but `return()` detaches/cleans up without resolving or rejecting that stored pending read.\n\n### Additional information\n\n_No response_","author":{"url":"https://github.com/trivikr","@type":"Person","name":"trivikr"},"datePublished":"2026-05-23T16:27:55.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":1},"url":"https://github.com/63519/node/issues/63519"}