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{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"fs.mkdtempDisposableSync() / fsPromises.mkdtempDisposable() throw and leak the directory when the path is a Buffer","articleBody":"### Version\n\nv27.0.0-nightly20261007aa1bf2cc37 (main at 6d5e309871)\n\n### Platform\n\nLinux x64\n\n### Subsystem\n\nfs\n\n### What steps will reproduce the bug?\n\n```js\nconst fs = require('node:fs');\nconst os = require('node:os');\nconst path = require('node:path');\n\nconst base = fs.mkdtempSync(path.join(os.tmpdir(), 'repro-'));\nconst prefix = path.join(base, 'x-');\n\nfor (const args of [[Buffer.from(prefix)], [prefix, { encoding: 'buffer' }]]) {\n  try {\n    fs.mkdtempDisposableSync(...args);\n  } catch (err) {\n    console.log(err.message);\n    console.log('left behind:', fs.readdirSync(base));\n  }\n}\n```\n\n`fs.promises.mkdtempDisposable()` behaves the same way.\n\n### How often does it reproduce? Is there a required condition?\n\nAlways, whenever the created path is a Buffer: the prefix is a Buffer, or `encoding` is `'buffer'`.\n\n### What is the expected behavior? Why is that the expected behavior?\n\nBoth calls return the disposable object with a Buffer `path`, and `remove()` deletes the directory. The docs list `path` as `{string|Buffer}`, and since #64397 a Buffer prefix defaults `encoding` to `'buffer'`.\n\n### What do you see instead?\n\n```\nThe \"paths[1]\" argument must be of type string. Received an instance of Buffer\nleft behind: [ 'x-Kx8KEG' ]\nThe \"paths[1]\" argument must be of type string. Received an instance of Buffer\nleft behind: [ 'x-Kx8KEG', 'x-gV98fq' ]\n```\n\nThe `ERR_INVALID_ARG_TYPE` is thrown after the directory has been created. The caller never gets the disposable object, so nothing removes the directory.\n\n### Additional information\n\nAfter `binding.mkdtemp()` creates the directory, both functions stash its absolute path for `remove()` with `pathModule.resolve(cwd, path)`, and `path.resolve()` only accepts strings. The `{ encoding: 'buffer' }` form has failed this way since `mkdtempDisposable()` was added in #58516; #64397 made every Buffer prefix take the same path.\n\nI have a fix and will open a PR.\n","author":{"url":"https://github.com/gengjiawen","@type":"Person","name":"gengjiawen"},"datePublished":"2026-10-08T06:52:52Z","url":"https://github.com/nodejs/node/issues/66593"}