pull-request.yml

name: Pull Request
on: 
  # trigger on pull request to main
  pull_request:
    branches:
      - main
  # allow triggering manually for debugging & testing workflow
  workflow_dispatch:
jobs:
  get-version:
    name: Get package.json "version"
    runs-on: ubuntu-latest
    # map the job outputs to step outputs
    outputs:
      version: ${{ steps.parse-step.outputs.version }}
    steps:
      - uses: actions/checkout@v2
      - name: Parse version From package.json
        id: parse-step
        run: |
          regex='"version" *: *"([0-9]+\.[0-9]+\.[0-9]+)"'
          [[ `cat package.json` =~ $regex ]] && echo "::set-output name=version::${BASH_REMATCH[1]}"
  check-version-changelog:
    name: Check version & CHANGELOG
    runs-on: ubuntu-latest
    needs: get-version
    steps:
      - uses: actions/checkout@v2
      - name: Verify the "version" in package.json hasn't already been released
        run: |
          git fetch --prune --unshallow --tags
          tag_match=`git tag -l v${{ needs.get-version.outputs.version }}`
          [[ -z "$tag_match" ]]
      - name: Check CHANGELOG.md has notes for the package.json "version"
        run: |
          grep "## *\[${{ needs.get-version.outputs.version }}\]" CHANGELOG.md
  check-version-incremented:
    # checks that one of the MAJOR.MINOR.PATCH versions is updated by 1, all trailing versions must be 0
    name: Check version incremented
    runs-on: ubuntu-latest
    needs: get-version
    steps:
      - uses: actions/checkout@v2
        with:
          # check out the branch PR is merging into
          ref: ${{ github.base_ref }}
      - name: Fetch version From package.json from base branch
        run: |
          regex='"version" *: *"([0-9]+\.[0-9]+\.[0-9]+)"'
          [[ `cat package.json` =~ $regex ]] && echo "OLD_VERSION=${BASH_REMATCH[1]}" >> $GITHUB_ENV
      # script to validate version chnage.  it is in-line instead of referencing a
      # file so it'l work calls from external repositories
      - name: Compare pull request version change against base branch version
        run: |
          VERSION=${{ needs.get-version.outputs.version }}
          echo "Checking version change from $OLD_VERSION to $VERSION"
          IFS='.'
          read -a OLD <<< "$OLD_VERSION"
          read -a NEW <<< "$VERSION"
          error () { echo $1; exit 1; }
          if [ ${NEW[0]} -eq ${OLD[0]} ] ; then
              if [ ${NEW[1]} -eq ${OLD[1]} ] ; then
                  if [ $(( ${NEW[2]} - ${OLD[2]} )) -ne 1 ]; then
                      error "PATCH version must increment by 1"
                  fi
              elif [ $(( ${NEW[1]} - ${OLD[1]} )) -eq 1 ] ; then
                  if [ ${NEW[2]} -ne 0 ] ; then
                      error "PATCH version must be set to 0"
                  fi
              else
                  error "MINOR version incremented incorrectly from ${OLD[1]} to ${NEW[1]}"
              fi
          elif [ $(( ${NEW[0]} - ${OLD[0]} )) -eq 1 ] ; then
              if [[ ${NEW[1]} -ne 0 || ${NEW[2]} -ne 0 ]] ; then
                  error "MINOR and PATCH version must be set to 0"
              fi
          else
              error "MAJOR version incremented incorrectly from ${OLD[0]} to ${NEW[0]}"
          fi