Drop-in Github workflow for Haskell projects using stack.

style.yaml

name: Code Style

on:
  pull_request:
    branches: [ "master" ]
  push:
    branches: [ "master" ]
    tags: [ "*.*.*" ]

jobs:
  build:
    strategy:
      matrix:
        os: [ubuntu-latest]

    runs-on: ${{ matrix.os }}
    steps:
    - name: 📥 Checkout repository
      uses: actions/checkout@v1

    - name: ✍  Check hlint and stylish
      run: |
        curl -sSL https://raw.github.com/ndmitchell/hlint/master/misc/run.sh | sh -s .
        curl -sSL https://raw.github.com/jaspervdj/stylish-haskell/master/scripts/latest.sh | sh -s $(find . -type f -name "*.hs" ! -path "*.stack-work*") -i
        if [ -z "$(git status --porcelain)" ]; then
            echo "No style errors detected."
        else
            echo "Style errors detected:"
            git --no-pager diff
            exit 1
        fi

workflow.yaml

name: Continuous Integration

on:
  pull_request:
    branches: [ "master" ]
  push:
    branches: [ "master" ]
    tags: [ "*.*.*" ]

jobs:
  build:
    strategy:
      matrix:
        os: [ubuntu-latest]

    runs-on: ${{ matrix.os }}
    steps:
    - name: 💽 Install OS Packages
      uses: mstksg/get-package@v1
      with:
        apt-get: libgmp-dev 

    - name: 📥 Checkout repository
      uses: actions/checkout@v1

    - name: 🧰 Setup Stack
      uses: mstksg/setup-stack@v1

    - name: 🔑 Cache Key
      id: cache_key
      run: echo ::set-output name=key::$(md5sum stack.yaml | awk '{print $1}')

    - name: 💾 Cache Dependencies
      id: cache
      uses: actions/cache@v1
      with:
        path: ~/.stack
        key: ${{ matrix.os }}-${{ steps.cache_key.outputs.key }}

    - name: 🏷️ Variables
      id: variables
      run: |
        echo ::set-output name=pkg_name::$(cat *.cabal | grep "name:" | sed "s/name:\s*\(.*\)/\1/")

    - name: 📸 Build Snapshot
      if: steps.cache.outputs.cache-hit != 'true'
      run: |
        stack --no-terminal test --bench --only-snapshot

    - name: 🔨 Build & Test
      run: |
        stack --no-terminal test --bench --haddock --no-haddock-deps --no-run-benchmarks
        mkdir -p dist/haddock && mv $(stack path --local-install-root)/doc/* dist/haddock
        sed -i 's@href="[^"]*/doc/\([^"]*.html\)"@href="\1"@g' dist/haddock/index.html
        wget -O Makefile https://gist.githubusercontent.com/KtorZ/0c7411f9bda2db1b3e0ded2ef0c40381/raw/1f818bd0385d8d917903e3f67ee3bfee3002de7a/Makefile
        mkdir -p .coverage && touch .coverage/template.overlay
        DESTDIR=dist/coverage make report && DESTDIR=dist/coverage make badge
      env:
        PKG_NAME: ${{ steps.variables.outputs.pkg_name }}

    - name: 📘 Publish Documentation
      if: matrix.os == 'ubuntu-latest' && github.event_name == 'push'
      uses: peaceiris/actions-gh-pages@v3
      with:
        github_token: ${{ secrets.GITHUB_TOKEN }}
        publish_dir: dist
        enable_jekyll: true

  release:
    needs: [build]
    if: ${{ startsWith(github.ref, 'refs/tags') }}
    runs-on: ubuntu-latest
    steps:
    - name: 📥 Checkout repository
      uses: actions/checkout@v1

    - name: 🚀 Release
      uses: docker://antonyurchenko/git-release:latest
      env:
        GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
        DRAFT_RELEASE: "true"
        PRE_RELEASE: "false"
        CHANGELOG_FILE: "ChangeLog.md"
        ALLOW_EMPTY_CHANGELOG: "false"
        ALLOW_TAG_PREFIX: "true"

I would suggest to change the script in line 24 to this one, as github changed the way it works now to retrieve the latest stylish-haskell release file.

https://raw.githubusercontent.com/cad0p/uu-afp-2021-assign2/master/scripts/stylish-haskell.sh