update_cache.yml

name: Cache Third Party Dependencies
# This is separate from the other build action in the hope that it can cache
# things on the main branch, which can thus be reused across multiple PRs. Per
# https://github.com/actions/cache/blob/v3/tips-and-workarounds.md#use-cache-across-feature-branches
# caches cannot be reused across feature branches, so we need a cache on the
# main branch instead.

on:
  pull_request:
    types:
      - closed

permissions:
  contents: read

jobs:
  build_when_merged:
    name: Build on ${{ matrix.os }}
    if: github.event.pull_request.merged == true  # Don't run unless we merged
    runs-on: ${{ matrix.os }}
    strategy:
      matrix:
        os:
          - macos-latest
          - ubuntu-latest
    steps:
      - name: Cache third-party libraries
        uses: actions/cache@v4
        with:
          key: ${{ matrix.os }}-
          restore-keys: |
            ${{ matrix.os }}-
          path: |
            ~/.stack
            ~/.local/bin
      - name: Check out code
        uses: actions/checkout@v4
      - name: Build project
        uses: freckle/stack-action@v5
        with:
          test: false