publish-rubygem.yml

name: Publish a Rubygem

on:
  workflow_call:
    inputs:
      gem_name:
        required: false
        type: string
        default: ${{ github.event.repository.name }}
    secrets:
      GEM_HOST_API_KEY:
        required: true

jobs:
  publish:
    name: Publish gem
    runs-on: ubuntu-latest
    permissions:
      contents: write
    steps:
    - uses: actions/checkout@v4
      with:
        show-progress: false
    - uses: ruby/setup-ruby@v1
      with:
        rubygems: latest
        bundler-cache: true
    - name: "Determine HEAD of default branch"
      id: fetch_default_branch_head
      run: echo "sha=$(git ls-remote origin HEAD | cut -f 1)" >> "$GITHUB_OUTPUT"
    - if: github.sha == steps.fetch_default_branch_head.outputs.sha
      name: "Check if gem needs publishing"
      env:
        GEM_NAME: ${{ inputs.gem_name }}
        GEM_HOST_API_KEY: ${{ secrets.GEM_HOST_API_KEY }}
      run: |
        local_version=$(ruby -r rubygems -e "puts Gem::Specification::load('$GEM_NAME.gemspec').version")
        remote_version=$(gem list --exact --remote "$GEM_NAME")
        if [[ "$remote_version" != "$GEM_NAME (${local_version})" ]]; then
          gem build "${GEM_NAME}.gemspec"
          gem push "${GEM_NAME}-${local_version}.gem"
        else
          echo "::notice title=Gem version already published::Skipping gem publish because version (${local_version}) is already published"
        fi

        if ! git ls-remote --tags --exit-code origin "v${local_version}"; then
          git tag "v${local_version}"
          git push --tags
        else
          echo "::notice title=Tag already exists::Skipping git tagging because tag (v${local_version}) already exists"
        fi
    - if: github.sha != steps.fetch_default_branch_head.outputs.sha
      name: "Skip publish: commit is not HEAD of default branch"
      run: |
        echo "Skipping publish because commit ($GITHUB_SHA) isn't the HEAD of the default branch ($DEFAULT_BRANCH_HEAD_SHA)" >> "$GITHUB_JOB_SUMMARY"