corepack is not removed when downgrading node

[Tobbe Lundberg]

Bug Report

Summary

corepack is not removed when downgrading node

If I understand correctly corepack should be available with node v >= 16.9 (from reading n's changelog https://github.com/tj/n/blob/master/CHANGELOG.md#750-2021-09-26)

So if/when I downgrade to node 16.0 I should no longer have access to corepack

Steps to Reproduce

❯ n 18
  installing : node-v18.18.2
       mkdir : /usr/local/n/versions/node/18.18.2
       fetch : https://nodejs.org/dist/v18.18.2/node-v18.18.2-darwin-arm64.tar.xz
     copying : node/18.18.2
   installed : v18.18.2 (with npm 9.8.1)

❯ corepack -v
0.19.0

❯ n 20
  installing : node-v20.10.0
       mkdir : /usr/local/n/versions/node/20.10.0
       fetch : https://nodejs.org/dist/v20.10.0/node-v20.10.0-darwin-arm64.tar.xz
     copying : node/20.10.0
   installed : v20.10.0 (with npm 10.2.3)
   
❯ corepack -v
0.22.0

❯ n 16.0
  installing : node-v16.0.0
       mkdir : /usr/local/n/versions/node/16.0.0
       fetch : https://nodejs.org/dist/v16.0.0/node-v16.0.0-darwin-arm64.tar.xz
     copying : node/16.0.0
   installed : v16.0.0 (with npm 7.10.0)
   
❯ corepack -v
0.22.0

Expected Behaviour

corepack should not be available when downgrading to a version of node that didn't ship with corepack

Actual Behaviour

corepack is left at whatever version it was before downgrading. So if I previously was on node 18.18.2 I keep corepack v 0.19.0. If I downgrade from node 20.10.0 I keep corepack v 0.22.0

Other Information

n was initially installed by homebrew. I kept the default directories for where it wants to manage node versions. I updated permissions on those directories to allow access.

❯ realpath $(which corepack)
/usr/local/lib/node_modules/corepack/dist/corepack.js

Configuration Details

❯ n --version
v9.2.0

❯ command -v node
/usr/local/bin/node

❯ node -p process.platform
darwin

[John Gee]

(Thanks for the clear description.)

Simplifying a bit, n installs the specified version of Node.js over whatever is there. corepack is included as a global npm package rather than a separate binary. While earlier versions of Node.js did not include corepack, the user may have installed it themselves.

The current implementation of n just leaves corepack alone when you install older Node.js versions without core pack.

Here is an example scenario where it would not make sense for n to delete corepack:

% n 15
     copying : node/15.14.0
   installed : v15.14.0 (with npm 7.7.6)
% corepack --version
zsh: command not found: corepack
% npm install -g corepack@0.17.2

added 1 package in 1s
% corepack --version
0.17.2
% n 16.0.0
     copying : node/16.0.0
   installed : v16.0.0 (with npm 7.10.0)
% corepack --version
0.17.2
% n lts
     copying : node/20.10.0
   installed : v20.10.0 (with npm 10.2.3)
% corepack --version
0.22.0

[Tobbe Lundberg]

Thanks for getting back to me.

corepack is included as a global npm package rather than a separate binary.

So to simulate a "clean" Node 15 installation I can just do this?

% n 15
% npm -g rm corepack

[John Gee]

Yes. (I would suggest doing the commands in the other order just in case the version of node makes a difference to the result of the uninstall.)

% npm -g rm corepack
% n 15

[Tobbe Lundberg]

Thank you!

I ran into this because I was debugging an issue that involved yarn, corepack and homebrew. That's now in a good enough state, so I'm (probably) not going to be messing with corepack at this level any more.

Thanks again for taking the time to assist here 🙏