Build Error at Setup Ruby Stage of Build and Deploy on Actions

Symptom

The Setup Ruby step fails: the runner "was detected as self-hosted".

Cause

The workflow pinned an old ruby/setup-ruby (v1.161.0) that predates support for current runner images.

Fix

Pin ruby/setup-ruby to v1.195.0 or later.

Applies to

GitHub Actions workflows that set up Ruby, such as Jekyll sites on GitHub Pages

Issue

I recently tried to push updates to my GitHub Pages hosted site (powered by Jekyll Theme) and got the following error at the 'Build' stage.

text

Run ruby/setup-ruby@8575951200e472d5f2d95c625da0c7bec8217c42
  with:
    ruby-version: 3.1
    bundler-cache: true
    cache-version: 0
Error: The current runner (ubuntu-24.04-x64) was detected as self-hosted because the platform does not match a GitHub-hosted runner image (or that image is deprecated and no longer supported).
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 3.1.4 /opt/hostedtoolcache/Ruby/3.1.4/x64
Once that completes successfully, mark it as complete with:
$ touch /opt/hostedtoolcache/Ruby/3.1.4/x64.complete
It is your responsibility to ensure installing Ruby like that is not done in parallel.

Cause

#596 was released in https://github.com/ruby/setup-ruby/releases/tag/v1.177.0

My workflow is using older version.

Example:

yml

uses: ruby/setup-ruby@8575951200e472d5f2d95c625da0c7bec8217c42 # v1.161.0

Solution

I updated to newer Ruby version:

Example:

yml

uses: ruby/setup-ruby@086ffb1a2090c870a3f881cc91ea83aa4243d408 # v1.195.0

See my workflow after the change