René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"Buffer.prototype.indexOf returns a negative (int32-wrapped) position for matches beyond 2 GiB","articleBody":"### Version\n\nv26.10.0 and v24.21.0 (official win-x64 builds); v22.22.2 on Linux x64; first seen on v24.16.0 and on Node 24.20.0 as embedded in Electron 43.6.0\n\n### Platform\n\n```text\nWindows 10 22H2 x64 (build 19045.6466), 64 GB RAM; also Linux x86_64\n```\n\n### Subsystem\n\nbuffer\n\n### What steps will reproduce the bug?\n\n```js\nconst big = Buffer.alloc(2 ** 31 + 4096, 97);\nconst hit = 2 ** 31 + 100;\nbig[hit] = 10;\nconsole.log(big.indexOf(10, 2 ** 31 + 50));                 // number needle\nconsole.log(big.indexOf(Buffer.from([10]), 2 ** 31 + 50));  // Buffer needle\nconsole.log(big.indexOf('\\n', 2 ** 31 + 50));               // string needle\n```\n\nFull script with a below-2 GiB control: `indexof_2gib.js` in https://gist.github.com/BlackWhiteYellow/f44e367254db24fbe20d7fe10002ab1f (needs ~4.5 GB of free RAM).\n\n### How often does it reproduce? Is there a required condition?\n\nAlways, when the match position is ≥ 2^31, on every version and platform listed above. Matches below 2^31 in a buffer just under 2 GiB are returned correctly.\n\n### What is the expected behavior? Why is that the expected behavior?\n\n`2147483748`, the byte offset of the match. `Buffer.alloc` accepts lengths above 2^31 on 64-bit, so `indexOf` should return offsets in that range, as documented for the method.\n\n### What do you see instead?\n\n`-2147483548` for all three needle types, which equals `2147483748 − 2^32` (the offset truncated to int32).\n\n### Additional information\n\nConsumers that treat only `-1` as \"not found\" then move their cursor backwards; in the Claude Code VS Code extension this turns into an endless re-parse loop and an out-of-memory crash of the editor's extension host (downstream report linked in a comment below). nodejs/node#62711 (commit 49198d2, the fix for #62873) changed how the `end` parameter of indexOf/lastIndexOf is handled; it does not change how the found position is returned.","author":{"url":"https://github.com/BlackWhiteYellow","@type":"Person","name":"BlackWhiteYellow"},"datePublished":"2026-09-25T18:12:53Z","url":"https://github.com/nodejs/node/issues/66294"}