René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"vfs: RealFSProvider readFileSync(fd) fails after backing file is renamed","articleBody":"### Version\n\nmain\n\n### Platform\n\n```text\nmacOS 26.5.0\n```\n\n### Subsystem\n\nvfs\n\n### What steps will reproduce the bug?\n\n```js\nimport fs from 'node:fs';\nimport os from 'node:os';\nimport path from 'node:path';\nimport vfs from 'node:vfs';\n\nconst realRoot = fs.mkdtempSync(path.join(os.tmpdir(), 'vfs-real-root-'));\nconst mountPoint = fs.mkdtempSync(path.join(os.tmpdir(), 'vfs-mount-'));\n\nconst mounted = vfs\n  .create(new vfs.RealFSProvider(realRoot), { emitExperimentalWarning: false })\n  .mount(mountPoint);\n\ntry {\n  fs.writeFileSync(path.join(realRoot, 'a.txt'), 'still readable');\n\n  const fd = fs.openSync(path.join(mountPoint, 'a.txt'), 'r');\n  fs.renameSync(path.join(realRoot, 'a.txt'), path.join(realRoot, 'b.txt'));\n\n  try {\n    console.log(fs.readFileSync(fd, 'utf8'));\n  } finally {\n    fs.closeSync(fd);\n  }\n} finally {\n  mounted.unmount();\n  fs.rmSync(realRoot, { recursive: true, force: true });\n  fs.rmSync(mountPoint, { recursive: true, force: true });\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\nIt should print `still readable`. An already-open `fd` should remain usable after the file is renamed, matching native filesystem behavior.\n\n### What do you see instead?\n\n`fs.readFileSync(fd, 'utf8')` throws `ENOENT` after the backing file is renamed. This shows RealFSProvider is trying to read through the original path.\n\n### Additional information\n\n_No response_","author":{"url":"https://github.com/trivikr","@type":"Person","name":"trivikr"},"datePublished":"2026-06-24T01:05:16.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":1},"url":"https://github.com/64103/node/issues/64103"}