flags.yml

name: Flags

defaults:
  run:
    shell: bash

# See: https://docs.github.com/en/actions/reference/workflow-syntax-for-github-actions#concurrency.
concurrency:
  group: ${{ github.head_ref }}-${{ github.workflow }}
  cancel-in-progress: true

on:
  pull_request:
    branches:
      - '**'

jobs:
  pre_job:
    runs-on: ubuntu-latest
    outputs:
      ghcs: ${{ steps.ghcs.outputs.ghcs }}
      should_skip: ${{ steps.skip_check.outputs.should_skip }}
    steps:
      # Need the repo checked out in order to read the file
      - uses: actions/checkout@v3
      - id: ghcs
        run: echo "ghcs=$(cat ./.github/workflows/supported-ghc-versions.json)" >> $GITHUB_OUTPUT
      - id: skip_check
        uses: fkirc/skip-duplicate-actions@v5.3.1
        with:
          cancel_others: false
          paths_ignore: '[ "**/docs/**"
                         , "**.md"
                         , "**/LICENSE"
                         , "**.nix"
                         , "flake.lock"
                         , "**/README.md"
                         , "FUNDING.yml"
                         , ".circleci/**"
                         , "**/stack*.yaml"
                         , ".gitlab-ci.yaml"
                         , ".gitlab/**"
                         ]'

  flags:
    if: needs.pre_job.outputs.should_skip != 'true'
    needs: pre_job
    runs-on: ${{ matrix.os }}
    strategy:
      fail-fast: true
      matrix:
        ghc: ${{ fromJSON(needs.pre_job.outputs.ghcs) }}
        os:
          - ubuntu-latest

    steps:
      - uses: actions/checkout@v3
        with:

            # By default, the `pull_request` event has a `GITHUB_SHA` env variable
            # set to the "last merge commit on the GITHUB_REF branch" (see
            # https://docs.github.com/en/actions/using-workflows/events-that-trigger-workflows#pull_request).
            # But we want to check out the latest commit on the branch whether or
            # not it is a merge commit, so this is how we do that.
            ref: "${{ github.event.pull_request.head.sha }}"

      - uses: ./.github/actions/setup-build
        with:
          ghc: ${{ matrix.ghc }}
          os:  ${{ runner.os }}

      # The purpose of this job is to ensure that the build works even with flags
      # in their non-default settings. Below we:
      # - enable flags that are off by default
      # - disable flags that are on by default
      - name: Configue non-default flags for all components
        run: |
          cabal configure \
              --constraint "haskell-language-server +pedantic" \
              --constraint "hls-graph +embed-files +pedantic +stm-stats" \
              --constraint "ghcide +ekg +executable +test-exe" \
              --constraint "hls-plugin-api +pedantic -use-fingertree"
          cat cabal.project.local

      - name: Build everything with non-default flags
        run: cabal build all

  flags_post_job:
    if: always()
    runs-on: ubuntu-latest
    needs: [pre_job, flags]
    steps:
      - run: |
          echo "jobs info: ${{ toJSON(needs) }}"
      - if: contains(needs.*.result, 'failure')
        run: exit 1
      - if: contains(needs.*.result, 'cancelled') && needs.pre_job.outputs.should_skip != 'true'
        run: exit 1