René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"ffi: exportArrayBufferView() inconsistently handles detached views","articleBody":"### Version\n\nmain\n\n### Platform\n\n```text\nmacOS 26.6.0\n```\n\n### Subsystem\n\nffi\n\n### What steps will reproduce the bug?\n\n`repro.c`\n```c\nvoid* destination(void) {\n  static unsigned char byte;\n  return &byte;\n}\n```\n\n`repro.js`\n```js\nimport { dlopen, suffix, exportArrayBuffer, exportArrayBufferView } from 'node:ffi';\n\nconst { lib, functions } = dlopen(`./repro.${suffix}`, {\n  destination: { arguments: [], return: 'pointer' },\n});\n\nconst pointer = functions.destination();\n\nfunction detached(makeValue) {\n  const buffer = new ArrayBuffer(1);\n  const value = makeValue(buffer);\n  structuredClone(buffer, { transfer: [buffer] });\n  return value;\n}\n\nfunction run(name, fn) {\n  try {\n    fn();\n    console.log(`${name}: accepted`);\n  } catch (error) {\n    console.log(`${name}: ${error.code ?? error.name}: ${error.message}`);\n  }\n}\n\nrun('ArrayBuffer', () => {\n  exportArrayBuffer(detached((buffer) => buffer), pointer, 1);\n});\n\nrun('Uint8Array', () => {\n  exportArrayBufferView(\n    detached((buffer) => new Uint8Array(buffer)),\n    pointer,\n    1,\n  );\n});\n\nrun('DataView', () => {\n  exportArrayBufferView(\n    detached((buffer) => new DataView(buffer)),\n    pointer,\n    1,\n  );\n});\n\nlib.close();\n```\n\nCommands to run:\n```sh\n$ cc -dynamiclib -o repro.dylib repro.c\n$ node --no-warnings --experimental-ffi repro.js\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\nAll detached inputs should be rejected consistently, preferably with Node.js’s `ERR_INVALID_ARG_VALUE`.\n\n### What do you see instead?\n\n```console\nArrayBuffer: ERR_INVALID_ARG_VALUE: ArrayBuffer is detached\nUint8Array: accepted\nDataView: TypeError: Cannot perform get DataView.prototype.byteLength on a detached or out-of-bounds ArrayBuffer\n```\n\nA detached `ArrayBuffer` produces `ERR_INVALID_ARG_VALUE`, a detached `Uint8Array` is accepted, and a detached `DataView` produces a V8 `TypeError`\n\n### Additional information\n\nNoticed while working on https://github.com/nodejs/node/issues/65082","author":{"url":"https://github.com/trivikr","@type":"Person","name":"trivikr"},"datePublished":"2026-08-06T15:13:41Z","url":"https://github.com/nodejs/node/issues/65085"}