[BUG] npm install in a workspaces environment requires admin permissions on Windows

[RoystonS]

Current Behavior:

npm install in a workspaces environment fails if the current user is not running under administrator privileges because directory symlinks can't be created on Windows without admin privilege (or some rather non-standard configuration)

Expected Behavior:

npm install would ideally 'just work' on Windows, which could be done by using Windows 'junctions' instead of directory symlinks. These are pretty much the same as directory symlinks but don't require admin permissions.

(This is what yarn does, incidentally. I'd love to be able to move back from yarn to npm, and workspace support is the killer feature for us.)

With the current behaviour, npm 7 workspace support will be broken on Windows unless the user runs as admin or does some non-trivial configuration to enable the creation of directory symlinks. (No, I don't know why Windows requires this hoop-jumping just to make symlinks, but it does. It's grim. But junctions are an easy workaround for it.)

Steps To Reproduce:

1. Create a simple workspaces environment on Windows
2. run npm install

See error:

npm ERR! code EPERM
npm ERR! syscall symlink
npm ERR! path ..\..\packages\pkg2
npm ERR! dest C:\Dev\monorepo\node_modules\@my\pkg2
npm ERR! errno -4048
npm ERR! Error: EPERM: operation not permitted, symlink '..\..\packages\pkg2' -> 'C:\Dev\monorepo\node_modules\@my\pkg2'npm ERR!  [Error: EPERM: operation not permitted, symlink '..\..\packages\pkg2' -> 'C:\Dev\monorepo\node_modules\@my\pkg2'] {
npm ERR!   errno: -4048,
npm ERR!   code: 'EPERM',
npm ERR!   syscall: 'symlink',
npm ERR!   path: '..\\..\\packages\\pkg2',
npm ERR!   dest: 'C:\\Dev\\monorepo\\node_modules\\@my\\pkg2'
npm ERR! }
npm ERR!
npm ERR! The operation was rejected by your operating system.
npm ERR! It's possible that the file was already in use (by a text editor or antivirus),
npm ERR! or that you lack permissions to access it.
npm ERR!
npm ERR! If you believe this might be a permissions issue, please double-check the
npm ERR! permissions of the file and its containing directories, or try running
npm ERR! the command again as root/Administrator.

Having to run as administrator isn't a realistic workaround for this sort of scenario; it would cause a lot of extra effort modifying build machines and scripts to be able to switch to administrator mode, and would massively weaken security as a result.

Environment:

OS: Windows 10
Node: 12.18.3
npm: 7.0.0-rc.3

[salvoravida]

Hi, pr that fix it

npm/arborist#162

[RoystonS]

Lovely - thank you. Certainly looks like it'll fix it.

(Not sure how that resulting failing build's going to be fixed though. Dealing with a mandated 100% branch coverage for something that needs platform-specific logic is going to be a little 'tricky'...)

[CAM-Gerlach]

For the record, I can confirm this also occurs . Node 15.0.1, npm 7.0.3 (latest current) but not Node 14.15.0 , npm 6.14.8 (latest LTS) when simply doing a regular install with npm install on packages that specified certain (e.g. test) dependencies as local paths, like igorshubovych/markdownlint-cli .

As discussed in pre-commit/pre-commit#1681 , this makes Node 15/npm 7 unusable for running this popular hook on Windows, unless all developers either work in an admin console, or manually enable symlink support (neither of which isn't really feasible given we get a large number of contributors who are students, scientists, engineers or beginning programmers, and the goal with pre-commit is to greatly reduce the barrier to entry, not increase it).

Therefore, fixing this would be greatly appreciated! I'm a Python developer, not a Node whiz, but I can try to help test if needed. Thanks!

[ljharb]

What about with npm v7.0.7?