check-api.yml

name: Check API

on:
  push:
    paths-ignore:
      - "doc/**"
      - "**/README.md"
      - "CONTRIBUTING.md"
      - "changelog.d/**"
      # only top level for these, because various test packages have them too
      - "*/ChangeLog.md"
      - "*/changelog.md"
      - "release-notes/**"
    branches:
      - master
  pull_request:
    paths-ignore:
      - "doc/**"
      - "**/README.md"
      - "CONTRIBUTING.md"
      - "changelog.d/**"
      - "*/ChangeLog.md"
      - "*/changelog.md"
      - "release-notes/**"
  release:
    types:
      - created
  workflow_call:

jobs:
  check-api:
    name: Check API using ${{ matrix.sys.os }} ghc-${{ matrix.ghc }}
    runs-on: ${{ matrix.sys.os }}
    strategy:
      matrix:
        # we check API only on one platform and ghc release, since it shouldn't
        # vary elsewhere (hopefully) and the API tracer is sensitive to both
        sys:
          - { os: ubuntu-latest }
        ghc:
          [
            # print-api only supports a small subset of ghc versions
            "9.10.1",
          ]

    steps:

      - uses: actions/checkout@v4

      - uses: haskell-actions/setup@v2
        id: setup-haskell
        with:
          ghc-version: ${{ matrix.ghc }}
          cabal-version: 3.12.1.0 # see https://github.com/haskell/cabal/pull/10251
          ghcup-release-channel: https://raw.githubusercontent.com/haskell/ghcup-metadata/master/ghcup-prereleases-0.0.8.yaml

      # I was going to use the canned action, but it only supports a single package and reinstalls the same binary each time
      - name: Install print-api
        run: |
          wget -q https://github.com/Kleidukos/print-api/releases/download/v0.1.0.1/print-api-0.1.0.1-Linux-static-${{ matrix.ghc }}-x86_64.tar.gz
          tar -xzf print-api-0.1.0.1-Linux-static-${{ matrix.ghc }}-x86_64.tar.gz
          mkdir -p "$HOME/.local/bin"
          mv print-api "$HOME/.local/bin/print-api"
          chmod +x "$HOME/.local/bin/print-api"
          echo "$HOME/.local/bin" >> $GITHUB_PATH

      # print-api needs environment files. It also doesn't make a lot of sense to use the cached builds, sadly,
      # since they're special in different ways (bootstrap and validate) and we want a vanilla build. And there
      # isn't enough cache space to make a third cache, even though this is a very limited build.
      - name: Build Cabal with environment files
        run: |
          cabal build Cabal-syntax Cabal cabal-install-solver --write-ghc-environment-files=always
          if test -d Cabal-hooks; then
            cabal build Cabal-hooks --write-ghc-environment-files=always
          fi

      - name: Generate APIs
        run: make generate-api

      # upload the new API records as artifacts, since there's no guarantee that a contributor could produce
      # them (wrong platform or ghc version). This must happen _before_ we check the API, because the
      # point is to have them available on API mismatch so they can be updated.
      - uses: actions/upload-artifact@v4
        with:
          name: Cabal-api
          path: '*.api'

      - name: Check APIs
        run: |
          rc=0
          if diff -c Cabal-syntax/Cabal-syntax-${{ matrix.ghc }}.api Cabal-syntax-${{ matrix.ghc }}.api >api.tmp; then
            :
          else
            echo "Cabal-syntax API changed"
            if [ $(wc -l < api.tmp) -lt 50 ]; then
              cat api.tmp
            else
              echo Diff too large for GitHub viewer
            fi
            rc=1
          fi
          if diff -c Cabal/Cabal-${{ matrix.ghc }}.api Cabal-${{ matrix.ghc }}.api >api.tmp; then
            :
          else
            echo "Cabal API changed"
            if [ $(wc -l < api.tmp) -lt 50 ]; then
              cat api.tmp
            else
              echo Diff too large for GitHub viewer
            fi
            rc=1
          fi
          if test \! -d Cabal-hooks; then
            echo "No Cabal-hooks in this version"
          elif diff -c Cabal-hooks/Cabal-hooks-${{ matrix.ghc }}.api Cabal-hooks-${{ matrix.ghc }}.api >api.tmp; then
            :
          else
            echo "Cabal-hooks API changed"
            if [ $(wc -l < api.tmp) -lt 50 ]; then
              cat api.tmp
            else
              echo Diff too large for GitHub viewer
            fi
            rc=1
          fi
          if diff -c cabal-install-solver/cabal-install-solver-${{ matrix.ghc }}.api cabal-install-solver-${{ matrix.ghc }}.api >api.tmp; then
            :
          else
            echo "cabal-install-solver API changed"
            if [ $(wc -l < api.tmp) -lt 50 ]; then
              cat api.tmp
            else
              echo Diff too large for GitHub viewer
            fi
            rc=1
          fi
          if [ $rc -ne 0 ]; then
            echo "The new APIs are in the artifact uploaded in the previous step."
            exit $rc
          fi

  # See check-api.skip.yml for why we need this
  check-api-post-job:
    if: always()
    name: Check API post job
    runs-on: ubuntu-latest
    needs: check-api

    steps:
      - run: |
          echo "jobs info: ${{ toJSON(needs) }}"
      - if: contains(needs.*.result, 'failure') || contains(needs.*.result, 'cancelled')
        run: exit 1