elixir.yml

# This workflow uses actions that are not certified by GitHub.
# They are provided by a third-party and are governed by
# separate terms of service, privacy policy, and support
# documentation.

name: Elixir CI
env:
  MIX_ENV: test
on:
  push:
    branches: ["main"]
  pull_request:
    branches: ["main"]
permissions:
  actions: write
  contents: read
jobs:
  dupe_check:
    name: check for duplicate tasks
    # continue-on-error: true # Uncomment once integration is finished
    runs-on: ubuntu-latest
    # Map a step output to a job output
    outputs:
      should_skip: ${{ steps.skip_check.outputs.should_skip }}
    steps:
      - id: skip_check
        uses: fkirc/skip-duplicate-actions@v5
        with:
          paths_ignore: '["**.md", "docs/**"]'
          cancel_others: true
  run_checks:
    name: Run checks
    runs-on: ubuntu-latest
    needs: dupe_check
    if: needs.dupe_check.outputs.should_skip != 'true'
    steps:
      - uses: actions/checkout@v4
      - uses: DeterminateSystems/nix-installer-action@main
      - uses: DeterminateSystems/magic-nix-cache-action@main
      - uses: DeterminateSystems/flake-checker-action@main
      - name: Restore dependencies cache
        id: deps-cache
        uses: actions/cache@v4
        with:
          path: |
            deps
            _build
            priv/plts
            .nix-mix
            .nix-hex
          key: ${{ runner.os }}-mix-${{ hashFiles(format('{0}{1}', github.workspace, '/flake.*')) }}-${{ hashFiles(format('{0}{1}', github.workspace, '/mix.*')) }}
          restore-keys: |
            ${{ runner.os }}-mix-${{ hashFiles(format('{0}{1}', github.workspace, '/flake.*')) }}
            ${{ runner.os }}-mix-
      - name: Build dependencies
        if: steps.deps-cache.outputs.cache-hit != 'true'
        run: |
          # nix flake check # BUG: https://github.com/cachix/git-hooks.nix/issues/466
          mkdir -p priv/plts
          nix develop -c mix local.hex --force
          nix develop -c mix deps.get
          nix develop -c mix dialyzer --plt
          nix develop -c mix compile
      - name: Run pre-commit checks
        run: |
          nix develop -c pre-commit run --show-diff-on-failure --hook-stage=pre-merge-commit --color=always --all-files

# # NOTE: the above runs on all files regardless of if they changed. What would be better would be checking only the files in a P.R. that changed.
# # However, my attempt below to do so raises an error saying "unknown revision or path 'main..dev'" and I don't know how to fix it.
# - name: Run pre-commit checks
#   env:
#     HEAD_REF: ${{ github.head_ref }}
#     BASE_REF: ${{ github.base_ref }}
#   run: |
#     if [[ -n "$HEAD_REF" && -n "$BASE_REF" ]]; then
#       git fetch --depth=1 origin "$BASE_REF"
#       git fetch --depth=1 origin "$HEAD_REF"
#       nix develop -c pre-commit run --show-diff-on-failure --color=always --to-ref "$BASE_REF" --from-ref "$HEAD_REF"
#     else
#       nix develop -c pre-commit run --show-diff-on-failure --hook-stage=pre-merge-commit --color=always --all-files
#     fi