Self-hosted setup

[pronebird]

When using setup-ruby on self-hosted machine I see the following message:

The current runner (macos-16-x64) was detected as self-hosted because the self-hosted input was set.
In such a case, you should install Ruby in the $RUNNER_TOOL_CACHE yourself, for example using https://github.com/rbenv/ruby-build
You can take inspiration from this workflow for more details: https://github.com/ruby/ruby-builder/blob/master/.github/workflows/build.yml
$ ruby-build 3.3 /Users/zoomer/actions-runner/_work/_tool/Ruby/3.3/x64
Once that completes successfully, mark it as complete with:
$ touch /Users/zoomer/actions-runner/_work/_tool/Ruby/3.3/x64.complete
It is your responsibility to ensure installing Ruby like that is not done in parallel.

I don't understand this message. I want to use setup-ruby to avoid dealing with manual installation.