René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"vfs: mounted fs.promises.open returns internal VFS handle instead of FileHandle","articleBody":"### Version\n\nmain\n\n### Platform\n\n```text\nN/A\n```\n\n### Subsystem\n\nvfs\n\n### What steps will reproduce the bug?\n\n```js\nimport fs from 'node:fs/promises';\nimport path from 'node:path';\nimport vfs from 'node:vfs';\n\nconst virtualFs = vfs.create();\nvirtualFs.writeFileSync('/file.txt', 'hello');\n\nconst mountPoint = virtualFs.mount();\nconst handle = await fs.open(path.join(mountPoint, 'file.txt'), 'r');\n\nconsole.log({\n  constructorName: handle.constructor.name,\n  fd: handle.fd,\n  hasReadFile: typeof handle.readFile,\n  hasCreateReadStream: typeof handle.createReadStream,\n});\n\nawait handle.close();\nvirtualFs.unmount();\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\n`fs.promises.open()` should return the same public FileHandle shape as normal `node:fs/promises`, including a numeric `fd` property.\n\n\n\n### What do you see instead?\n\n```console\n{\n  constructorName: 'MemoryFileHandle',\n  fd: undefined,\n  hasReadFile: 'function',\n  hasCreateReadStream: 'function'\n}\n```\n\nmounted `fs.promises.open()` returns a VFS-internal `MemoryFileHandle` whose `fd` property is missing.\n\n### Additional information\n\nfs equivalent\n```js\nimport fs from 'node:fs/promises';\nimport os from 'node:os';\nimport path from 'node:path';\n\nconst dir = await fs.mkdtemp(path.join(os.tmpdir(), 'fs-promises-open-'));\nconst file = path.join(dir, 'file.txt');\n\nawait fs.writeFile(file, 'hello');\n\nconst handle = await fs.open(file, 'r');\n\nconsole.log({\n  constructorName: handle.constructor.name,\n  fd: handle.fd,\n  hasReadFile: typeof handle.readFile,\n  hasCreateReadStream: typeof handle.createReadStream,\n});\n\nawait handle.close();\nawait fs.rm(dir, { recursive: true, force: true });\n```\n\nExample Output\n```console\n{\n  constructorName: 'FileHandle',\n  fd: 18,\n  hasReadFile: 'function',\n  hasCreateReadStream: 'function'\n}\n```\n\nThe exact `fd` number varies, but it should be a number.","author":{"url":"https://github.com/trivikr","@type":"Person","name":"trivikr"},"datePublished":"2026-09-02T00:43:13Z","url":"https://github.com/nodejs/node/issues/65729"}