prettier-update.yml

# Note this is heavily taken and inspired from:
# https://github.com/typescript-eslint/typescript-eslint/blob/main/.github/workflows/prettier-update.yml

# This workflow is used to augment the capabilities of the renovate GitHub app by running a full
# `prettier --write` when renovate opens a PR to change the version of prettier.

name: Prettier Update

on:
  pull_request:
    branches:
      - master
    paths:
      - package-lock.json
      - package.json

concurrency:
  group: ${{ github.workflow }}-${{ github.event.number || github.ref }}
  cancel-in-progress: true

jobs:
  maybe_prettier_update:
    # Only run if it was the renovate bot that triggered the workflow (otherwise we'll create a loop)
    if: contains('["renovate[bot]"]', github.actor) == true

    name: Run prettier formatting if required
    runs-on: ubuntu-latest

    steps:
      - uses: actions/checkout@v4
        with:
          fetch-depth: 0
          ref: ${{ github.event.pull_request.head.ref }}
      - name: Setup Node
        uses: actions/setup-node@v4
        with:
          cache: npm
          node-version-file: .nvmrc

      - name: Check if prettier was changed as part of the latest commit on the PR
        id: prettier-package-check
        run: |
          git diff HEAD~1 -G"prettier" --exit-code package.json package-lock.json && echo "prettier unchanged" || echo "::set-output name=was-changed::true"

      - name: Run prettier formatting if prettier was changed and commit the results
        if: ${{ steps.prettier-package-check.outputs.was-changed == 'true' }}
        env:
          # We cannot use secrets.GITHUB_TOKEN for this because it is not permitted to kick off subsequent actions worfklow runs, so we use a PAT instead
          GITHUB_TOKEN: ${{ secrets.BOT_GIT_TOKEN }}
        run: |
          npm ci
          npm run lint:fix

          # Commit all the changes to the PR (see note on not being able to use secrets.GITHUB_TOKEN for this)
          git config user.name "${{ vars.BOT_NAME }}"
          git config user.email "${{ vars.BOT_NAME }}@users.noreply.github.com"

          # If the status is empty, there are no uncommitted changes
          if [[ -z $(git status --porcelain) ]]; then
            echo "No uncommitted changes"
          else
            git add --all
            git commit -m "chore: update formatting after prettier upgrade"
            git push
          fi