ci: run corepack enable before installing dependencies

[legobeat]

corepack is not currently supported in @actions/setup-node and this means installation of dependencies fail when using yarn >v1:

• Added option to enable corepack actions/setup-node#901

This hacks around it by running @actions/setup-node twice: once before checkout to install the node-version, so that corepack enable can be run, after which the normal flow starting with checkout can proceed.

Since .nvmrc is not available before checkout, it also implies not using .nvmrc to specify node-version for this workflow anymore.

An alternative to this would be forking @actions/setup-node with the patch from the PR linked above but sounds not worth it.

[Mrtenz]

this means installation of dependencies fail when using yarn >v1:

Not sure I understand. We're using Yarn 3 and 4 in several repos without problems.

[Mrtenz]

Should we not prefer the version in .nvmrc?

[mcmire]

According to the PR description, we are now running this first before checking out, so we don't have access to .nvmrc anymore.

[legobeat]

Yeah, I figured if we can't use it consistently for a job in a workflow, it's preferred to be consistent within the workflow.

[mcmire]

It looks like corepack may be already installed on ubuntu-latest? The reason I say that is that I'm reviewing solutions others have posted in the actions/setup-node ticket, specifically actions/setup-node#480 (comment), and it seems like we could do this without having to install Node twice:

Suggested change

	- name: Use Node.js
	uses: actions/setup-node@v4
	with:
	node-version-file: '.nvmrc'
	node-version: 'lts/*'
	- name: Install Yarn
	run: corepack enable
	- uses: actions/checkout@v4
	- name: Use Node.js and install dependencies
	uses: actions/setup-node@v4
	with:
	node-version: 'lts/*'
	- uses: actions/checkout@v4
	- name: Install Yarn via Corepack
	run: corepack enable
	- name: Use Node.js and install dependencies
	uses: actions/setup-node@v4
	with:
	node-version: '.nvmrc'

Perhaps you tried this already, but, thoughts?

[mcmire]

I was also traversing the chain of various attempts at adding Corepack support to setup-node, and apparently according to this comment Yarn is already installed on GitHub runners somehow, so we may wish to remove it so that the shim that Corepack installs doesn't conflict:

Suggested change

	- name: Use Node.js
	uses: actions/setup-node@v4
	with:
	node-version-file: '.nvmrc'
	node-version: 'lts/*'
	- name: Install Yarn
	run: corepack enable
	- uses: actions/checkout@v4
	- name: Use Node.js and install dependencies
	uses: actions/setup-node@v4
	with:
	node-version: 'lts/*'
	- uses: actions/checkout@v4
	- name: Uninstall existing Yarn
	run: npm -g uninstall yarn
	- name: Install Yarn via Corepack
	run: corepack enable
	- name: Use Node.js and install dependencies
	uses: actions/setup-node@v4
	with:
	node-version: '.nvmrc'

Then again, this doesn't make any sense since it would imply that npm is always preinstalled on GitHub runners. Just a suggestion though in case it works.

[legobeat]

I don't think this is directly related to here, in any case? Recall this has always been the case and we rely on @setup/node to override anything present in the local env. I suggest addressing any removal of already installed stuff separately from this PR.

(I also suspect that the corepack enable in the previous step will be done uneffective by the setup-node replacing local nodejs. But you're welcome to try variations as well)

[mcmire]

Thanks! I'll go ahead and merge this into my branch.