Updating a package that depends on yarn globally will override system yarn

[ahmedelgabri]

This is not an issue with yarn itself, but a current issue faced oclif/plugin-plugins#71 which is a dependency of netlify/cli#269

When yarn installs global packages they usually symlink global node_modules/.bin to /usr/local/bin so if you install a global package that depends on yarn, yarn will override the system installed yarn with the node_module/.bin/yarn one.

I can see this issue starting to get bigger after yarn v2 is released too.

This might be related to #2627, #3157

So is there is any workaround? Also how can this be prevented?

Not 100% sure but npm might also have this if npm is a dependency of a package too

Thanks to @bk3c, he managed to reproduce the issue (see oclif/plugin-plugins#71 (comment)) & I also confirm that this is the case for me too.

FWIW, I've been struggling with the effects of this for a few months, and finally figured it out enough to find this issue. I'm pretty sure I have a reproducible case, though I can't tell if this is actually yarn being broken or misused:

• my system yarn is via homebrew
• I have two globally installed packages that depend on this one (apollo and netlify-cli), and this is the only global dependency I have on yarn
• if I wipe my global yarn.lock and node_modules and reset all of the symlinks, I can do a yarn add to recreate both with no problems at all
• as soon as I do a yarn global upgrade or yarn global upgrade-interactive, the symlinks in /usr/local/bin are overwritten and now point to ~/.config/yarn/global/node_modules/.bin/yarn
• this is 100% reproducible, at least in my environment
• it's super-annoying

[ahmedelgabri]

After further investigation, it seems to be something related to my setup. Can't figure out what it is yet

[ahmedelgabri]

See the updated description /cc @bk3c