René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"stream/iter: zero-byte broadcast writes bypass backpressure and grow buffer unbounded","articleBody":"### Version\n\nmain\n\n### Platform\n\n```text\nmacOS 26.5.2\n```\n\n### Subsystem\n\nstream\n\n### What steps will reproduce the bug?\n\n```js\nimport { broadcast } from 'node:stream/iter';\n\nconst { writer, broadcast: channel } = broadcast({\n  budget: 16_384,\n  backpressure: 'strict',\n});\nconst readable = channel.push();\n\nlet accepted = 0;\nwhile (accepted \u003c 100_000 && writer.writevSync([])) accepted++;\n\nconsole.log({ accepted, canWrite: writer.canWrite });\n\nawait writer.end();\n\nlet entries = 0;\nfor await (const _ of readable) entries++;\n\nconsole.log({ entries });\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\n{ accepted: 100000, canWrite: true }\n{ entries: 0 }\n```\n\nZero-byte writes should be accepted as no-ops and create no buffer entries, preventing unbounded growth.\n\nFrom specification [§13.1.2 Broadcast backpressure](https://stream-iter.jasnell.me/#broadcast-backpressure)\n> The shared buffer cannot overwrite entries that the slowest consumer has not yet read.\n\n### What do you see instead?\n\n```console\n{ accepted: 100000, canWrite: true }\n{ entries: 100000 }\n```\n\nAll 100,000 empty batches are buffered.\n\n### Additional information\n\n_No response_","author":{"url":"https://github.com/trivikr","@type":"Person","name":"trivikr"},"datePublished":"2026-07-27T01:50:39Z","url":"https://github.com/nodejs/node/issues/64771"}