Resolve the realpath of linkFolder before symlinking

[apfelfabrik]

Summary

I was affected by the bug described here: #1297

Symlinks created by yarn link will be broken if there's a symlink somewhere in the config path. This fixes the problem for me.

fs.symlink seems to not resolve existing symlinks in the target path when creating new ones, resulting in broken symlinks. Resolving the realpath of linkFolder before creating the symlink fixes this.

Test plan

This was previously not working when ~/.config was a symlink:

➜  dep-a $ yarn link
yarn link v1.15.0-0
success Registered "@company/dep-a".
info You can now run `yarn link "@company/dep-a"` in the projects where you want to use this package and it will be used instead.
✨  Done in 0.34s.

➜  dep-a $ cd ../..

➜  parent $ yarn link "@company/dep-a"
yarn link v1.15.0-0
error No registered package found called "@company/dep-a".
info Visit https://yarnpkg.com/en/docs/cli/link for documentation about this command.

With this update, it is working. More details in the ticket, too.

[damncabbage]

Thanks for doing this; I personally just got bitten by this as well (my ~/.config being a symlink).

[jone]

I ran into this problem too (I link my dotfiles into the home directory). It would be great if this could get merged!

[nemoDreamer]

This solves the issue!
Too bad CI is failing 😢 ...

[apfelfabrik]

Wow, didn't know so many people cared. I'll have a look at why the CI is failing.

Edit: Turns out the tests on macOS run in a temporary folder that is also a symlink. Fixing the linking exposed a similar problem with linking the binaries on that platform, so I went and fixed that too. The fix seems to be complete now, at least I'm not aware what else to look at.

[waleedahmed3045]

Passed all the tests, no significant code changes

[apfelfabrik]

I've rebased the PR once more, I still think this is a worthwhile fix. The CI issues seem to not be related to this PR. It has been green in the past, and recent, unrelated, PRs against master fail with the same timeouts.

[apfelfabrik]

@waleedahmed3045, is there anything else I can do?

[svallory]

Is this ever going to be merged? I'm tired of going back to npm when I need to link packages. What can I do to help?

[corrjo]

Is yarn just not maintained?

[rodamaral]

Is yarn just not maintained?

By the way, for some reason the active development branch of yarn is not at this repository. It's at https://github.com/yarnpkg/berry

Not sure what it means for opened issues here...