René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"vfs: MemoryProvider allows renaming a directory into its own descendant","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 vfs from 'node:vfs';\n\nconst fs = vfs.create({ emitExperimentalWarning: false });\n\nfs.mkdirSync('/a/b', { recursive: true });\nfs.writeFileSync('/a/file.txt', 'data');\n\ntry {\n  fs.renameSync('/a', '/a/b/c');\n  console.log('rename succeeded');\n} catch (err) {\n  console.log('rename threw:', err.code);\n}\n\nconsole.log('/ entries:', fs.readdirSync('/'));\nconsole.log('/a exists:', fs.existsSync('/a'));\nconsole.log('/a/b/c exists:', fs.existsSync('/a/b/c'));\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\nThe rename should throw, typically `EINVAL`, and the tree should remain unchanged. A directory cannot be moved into its own descendant because that would create a cycle or orphan the directory hierarchy.\n\n### What do you see instead?\n\n```console\nrename succeeded\n/ entries: []\n/a exists: false\n/a/b/c exists: false\n```\n\nThe implementation moves `/a` into one of its own children, then removes the original root entry, detaching the whole subtree.\n\n### Additional information\n\n```js\nimport fs from 'node:fs';\nimport os from 'node:os';\nimport path from 'node:path';\n\nconst dir = fs.mkdtempSync(path.join(os.tmpdir(), 'native-rename-'));\n\ntry {\n  fs.mkdirSync(path.join(dir, 'a/b'), { recursive: true });\n  fs.writeFileSync(path.join(dir, 'a/file.txt'), 'data');\n\n  try {\n    fs.renameSync(path.join(dir, 'a'), path.join(dir, 'a/b/c'));\n    console.log('rename succeeded');\n  } catch (err) {\n    console.log('rename threw:', err.code);\n  }\n\n  console.log('root entries:', fs.readdirSync(dir));\n  console.log('a exists:', fs.existsSync(path.join(dir, 'a')));\n  console.log('a/b/c exists:', fs.existsSync(path.join(dir, 'a/b/c')));\n} finally {\n  fs.rmSync(dir, { recursive: true, force: true });\n}\n```\n\nOutput\n```console\nrename threw: EINVAL\nroot entries: [ 'a' ]\na exists: true\na/b/c exists: false\n```","author":{"url":"https://github.com/trivikr","@type":"Person","name":"trivikr"},"datePublished":"2026-07-04T13:58:39.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":0},"url":"https://github.com/64284/node/issues/64284"}