Fallback to default node version if .nvmrc file does not exist

[Th3S4mur41]

Description:
Currently using a node version file results in an error if the configured file is not found.

e.g. using .nvmrc

- uses: actions/setup-node@v3
  with:
    node-version-file: '.nvmrc'

Fails with the following error

The specified node version file at: /__w/actions/actions/.nvmrc does not exist

Justification:
When reusing workflows in multiple repositories, it will happen that some of them don't require a specific node version and therefor have no .nvmrc file.

In such cases, instead of failing it would be better to throw a warning and fallback to the default node version

Are you willing to submit a PR?
Yes

[dmitry-shibanov]

Hello @Th3S4mur41. Thank you for your feature request. I do not think it will be a right behaviour because if customers specify a path to nodejs's file they are sure that the file exists. Besides, throwing only a warning can lead to some unexpected behaviour when the project is supposed to be built with the exact node version.

[Th3S4mur41]

Hey @dmitry-shibanov. You are absolutely right when you use the action local workflows that are in the same repository as the .nvmrc.
With both in the same repository, you can definitely make sure it exists.

In the case of reusable workflows (e.g. all workflows are in a dedicated actions repository of an organization) though, you cannot control that all repositories in the organization define an .nvmrc file which is my use case.

I have two repositories that cannot yet use node 18 that was just declared LTS, and I have to force them down to node 16 using npmrc.
All the other repositories are just fine using latest node or node LTS and therefor do not need an .nvmrc file.

So the current workaround is to have an additional job in the workflows to check if .nvmrc exists and if it does, only add the node-version-file.
But having native support for this use case would be nicer

[dmitry-shibanov]

Hello @Th3S4mur41. I'm not sure it will be correct solution to add fallback to setup-node if the file is not found. I think it will be better to add check from your side on existing of .nvmrc file. For now I'm going to close the issue.