auto-update-dev-tools.yml

# On a schedule, this workflow checks whether new tool versions have been
# released. If so, this workflow runs `update-dev-tools.sh`, which updates the
# tool versions in the Dockerfile. It then opens and auto-merges an update PR.
name: dev-tools update
on:
  schedule:
    # run once, each monday+wednesday+friday, at 4AM PST (UTC-8:00)
    - cron: '0 12 * * 1,3,5'
  workflow_dispatch:

jobs:
  create-pr:
    runs-on: ubuntu-latest
    permissions:
      contents: read
      pull-requests: write

    steps:
      - uses: actions/checkout@v2

      - name: update dockerfiles
        run: src/update-dev-tools.sh

      - name: run diff
        run: git diff

      - name: Create PR
        uses: peter-evans/create-pull-request@v3
        id: create-pr
        with:
          title: '[Auto] Update hlint and fourmolu image'
          body: 'This PR should be approved once the latest HLS includes this fourmolu version.'
          branch: auto/update-image
          # Github won't run actions when triggered by a github token, intentional limitation.
          # Their workaround is to use personal tokens, we use a purpose-made token for fossabot.
          token: ${{ secrets.FOSSABOT_TOKEN }}

      - name: Enable auto-merge
        uses: peter-evans/enable-pull-request-automerge@v1
        if: steps.create-pr.outputs.pull-request-operation == 'created'
        with:
          # Same reason as above
          token: ${{ secrets.FOSSABOT_TOKEN }}
          merge-method: squash
          pull-request-number: ${{ steps.create-pr.outputs.pull-request-number }}