fs.symlink can’t create directory symlinks on Windows

[chris-morgan]

• Version: v8.9.4
• Platform: Windows 10, 64-bit, build 17083 (Windows Insider Preview). In developer mode (so normal users can create symlinks).
• Subsystem: fs

Using fs.symlinkSync( x, y, 'dir' ) to create a directory symlink is failing (EPERM: operation not permitted), while mklink /d is able to make the symlink.

Simplest example to demonstrate the issue:

C:\Users\me\AppData\Local\Temp>node
> require('fs').symlinkSync('abcdef', 'ghijkl', 'dir')
Error: EPERM: operation not permitted, symlink 'abcdef' -> 'C:\Users\me\AppData\Local\Temp\ghijkl'
    at Object.fs.symlinkSync (fs.js:1014:18)

File symlinks are fine; it’s only directory symlinks that are failing. It doesn’t matter whether the target path exists or not, it fails with the same EPERM error.

Meanwhile,

C:\Users\me\AppData\Local\Temp>mklink /d ghijkl abcdef
symbolic link created for ghijkl <<===>> abcdef

[seishun]

Can't reproduce on master.

[seishun]

It was fixed in a083786 (PR: #18260). cc @nodejs/lts

[chris-morgan]

For an idea of the context of this: ghost-cli creates a directory symlink as part of ghost install local, and if it fails then the result is incomplete and non-functional, so it’s broken on Windows. Having WSL, I worked around that by installing ghost-cli on the Ubuntu side instead of the Windows side, but that’s a workaround rather than a fix.

[bnoordhuis]

The libuv upgrade will make its way into node 8 eventually. Since there is nothing to do but wait I'll go ahead and close this out.

The relevant libuv PR: libuv/libuv#1706

[livingstonef]

This is still a problem. Any update?

[chris-morgan]

@livingstonef I now have 8.11.1, and it’s fixed there. If you have an older version of Node, try upgrading. If it’s the same or newer, ensure your Windows installation is in Developer Mode, and then please verify that my “simplest example to demonstrate the issue” does in fact not work for you; if it does work, then you probably have a different issue.

[flotwig]

fs.symlink appears to require admin privileges on Windows 10 for some reason. If anyone else runs into this, try running as admin.

[chris-morgan]

@flotwig For historical and security reasons, it requires either admin privileges, or for the machine to be in developer mode and the appropriate flag set in the API call (and that flag was what was missing). But yeah, this was fixed over a year ago now.

[flotwig]

Yeah, we're still using Node 8.9.3 (though upgrading soon!)

FWIW, I actually needed to pass type=junction to fs.symlink, that made running as admin unnecessary and made the symlinks actually work.

[OLEREO]

是的，我们仍在使用 Node 8.9.3（尽管很快就会升级！）

FWIW，我实际上需要传递type=junction给fs.symlink，这使得以管理员身份运行变得不必要并使符号链接实际工作。

Yeah, we're still using Node 8.9.3 (though upgrading soon!)

FWIW, I actually needed to pass type=junction to fs.symlink, that made running as admin unnecessary and made the symlinks actually work.

There are still some problems. Folders are created correctly, but the files are also recognized as folders and the soft links created do not work.

[citkane]

#18518 (comment)

FWIW, I actually needed to pass type=junction to fs.symlink, that made running as admin unnecessary and made the symlinks actually work.

Still true in node v16.17.0

[ghost]

This bug is still occurring on Node v18 LTS. Has this been fixed by a higher niode version? If not, this issue either needs to be reopened or referenced in a new issue.

[bnoordhuis]

@IRod22 v18.x never had this issue. I suspect you're misunderstanding the discussion here.

[ghost]

@bnoordhuis I am investigating a bug for imba/imba#768 where Node throws a EPERM error because Windows does not permit Node to create a symlink without administrative permissions. I did some googling, and the search results led me to this discussion.

[ghost]

Here's my node version:

> node -v
v18.12.1

[lqzhgood]

fs.symlink api need runnning as admin. but mklink don't

v18.16.0
windows 11

// need admin
// err.message EPERM: operation not permitted, symlink 'E:\Git\xx\i' -> 'E:\Git\xx\o'
fs.symlinkSync('i', 'o')

// this is ok
const { execSync } = require('child_process');
execSync('mklink /J o i', { windowsHide: true });