ci.yml

name: Elixir CI

# Define workflow that runs when changes are pushed to the
# `main` branch or pushed to a PR branch that targets the `main`
# branch.
on:
  push:
    branches: [ "main" ]
  pull_request:
    branches: [ "main" ]

# Sets the ENV `MIX_ENV` to `test` for running tests
env:
  MIX_ENV: test

permissions:
  contents: read

jobs:
  test:
    runs-on: ubuntu-latest
    name: Test on OTP ${{matrix.otp}} / Elixir ${{matrix.elixir}}
    strategy:
      # Specify the OTP and Elixir versions to use when building
      # and running the workflow steps.
      matrix:
        include:
          # minimum required versions
          - otp: "27.2.4"
            elixir: "1.17.3-otp-27"
          - otp: "27.2.4"
            elixir: "1.18.4-otp-27"
          - otp: "28.3.1"
            elixir: "1.18.4-otp-28"
          - otp: "27.2.4"
            elixir: "1.19.5-otp-27"
          - otp: "28.3.1"
            elixir: "1.19.5-otp-28"
          - otp: "28.3.1"
            elixir: "1.20.2-otp-28"
          - otp: "29.0.1"
            elixir: "1.20.2-otp-29"
            lint: true
    steps:
    # Step: Setup Elixir + Erlang image as the base.
    - name: Set up Elixir
      uses: erlef/setup-beam@v1
      with:
        otp-version: ${{matrix.otp}}
        elixir-version: ${{matrix.elixir}}

    # Step: Check out the code.
    - name: Checkout code
      uses: actions/checkout@v5

    # Step: Define how to cache deps. Restores existing cache if present.
    # Cache keys include the OTP and Elixir versions so matrix entries
    # never share BEAMs compiled by a different toolchain.
    - name: Cache deps
      id: cache-deps
      uses: actions/cache@v4
      env:
        cache-name: cache-elixir-deps
      with:
        path: deps
        key: ${{ runner.os }}-otp${{ matrix.otp }}-elixir${{ matrix.elixir }}-mix-deps-${{ hashFiles('**/mix.lock') }}
        restore-keys: |
          ${{ runner.os }}-otp${{ matrix.otp }}-elixir${{ matrix.elixir }}-mix-deps-

    # Step: Define how to cache the `_build` directory. After the first run,
    # this speeds up tests runs a lot. This includes not re-compiling our
    # project's downloaded deps every run.
    - name: Cache compiled build
      id: cache-build
      uses: actions/cache@v4
      env:
        cache-name: cache-compiled-build
      with:
        path: _build
        key: ${{ runner.os }}-otp${{ matrix.otp }}-elixir${{ matrix.elixir }}-mix-build-${{ hashFiles('**/mix.lock') }}
        restore-keys: |
          ${{ runner.os }}-otp${{ matrix.otp }}-elixir${{ matrix.elixir }}-mix-build-

    # Step: Download project dependencies. If unchanged, uses
    # the cached version.
    - name: Install dependencies
      run: mix deps.get

    # Step: Compile the project treating any warnings as errors.
    - name: Compiles without warnings
      run: mix compile --warnings-as-errors

    # Step: Download the segmentation dictionaries the tests rely on.
    - name: Download dictionaries
      run: mix unicode.string.download.dictionaries

    # Step: Check that the checked in code has already been formatted.
    - name: Check Formatting
      if: ${{ matrix.lint }}
      run: mix format --check-formatted

    # Step: Static code analysis.
    - name: Run credo
      if: ${{ matrix.lint }}
      run: mix credo --strict

    # Step: Execute the tests.
    - name: Run tests
      if: ${{ !matrix.lint }}
      run: mix test

    # Step: Execute the tests with coverage measurement on the lint entry.
    - name: Run tests with coverage
      if: ${{ matrix.lint }}
      run: mix test --cover

    # Step: Execute dialyzer. Runs on the lint entry only; a single
    # analysis per change is sufficient and avoids rebuilding a PLT for
    # every toolchain in the matrix.
    - name: Run dialyzer
      if: ${{ matrix.lint }}
      run: mix dialyzer