name: Build on `trunk`

on:
  push:
    branches:
      - main
  pull_request:
  schedule:
    # Every weekday, at 5:43 UTC
    - cron: '43 5 * * 1-5'

jobs:
  build:
    runs-on: ubuntu-latest

    steps:
      - name: Checkout code
        uses: actions/checkout@v4

      - name: Pick up a robust cache prefix
        id: setup
        run: |
          # Ensure that cache is flushed when trunk is updated
          cache_prefix="$(git ls-remote https://github.com/ocaml/ocaml.git refs/heads/trunk | cut -f 1)"
          echo "cache_prefix=$cache_prefix" >> "$GITHUB_OUTPUT"
          cat "$GITHUB_OUTPUT"

      - name: Install OCaml compiler
        uses: ocaml/setup-ocaml@v3
        with:
          ocaml-compiler: 'ocaml-variants.5.4.0+trunk'
          dune-cache: true
          cache-prefix: ${{ steps.setup.outputs.cache_prefix }}

      - name: Install ppxlib dependencies
        run: |
          opam install ./ppxlib.opam --deps-only

      - name: Show configuration
        run: |
          opam exec -- ocamlc -config
          opam config list
          opam exec -- dune printenv
          opam list

      - name: Build the ppxlib
        run: opam exec -- dune build -p ppxlib @install

      - name: Install test dependencies
        run: |
          opam install ./ppxlib.opam --deps-only -t
          opam exec -- dune build -p ppxlib @runtest
        continue-on-error: true