name: Check for ABI breaks

on:
  push:
    branches-ignore:
      - abi-break
  pull_request:
    branches-ignore:
      - abi-break

jobs:
  run-abidiff:
    name: Compare ABIs
    runs-on: ubuntu-22.04
    container:
      image: ghcr.io/managarm/mlibc-crossers:latest
    defaults:
      run:
        shell: bash
    steps:
      - name: Install prerequisites
        run: |
          apt-get update
          apt-get install -y ninja-build qemu-user \
                             python3-setuptools python3-jsonschema \
                             python3-pip abigail-tools
          pip install --break-system-packages -U xbstrap pyexpect meson

      - name: Checkout base branch
        if: ${{ github.base_ref }}
        uses: actions/checkout@v2
        with:
          path: mlibc-base
          ref: ${{ github.base_ref }}
          submodules: true
          fetch-depth: 4

      - name: Checkout managarm/mlibc#master
        if: ${{ github.base_ref == '' }}
        uses: actions/checkout@v2
        with:
          path: mlibc-base
          repository: managarm/mlibc
          submodules: true
          ref: master
          fetch-depth: 4

      - name: Checkout branch
        uses: actions/checkout@v2
        with:
          path: mlibc-branch
          submodules: true

      - name: Determine base ref
        run: |
          master_hash="$(git -C mlibc-base rev-parse HEAD)"
          branch_hash="$(git -C mlibc-branch rev-parse HEAD)"
          printf '%s\n' "$master_hash" "$branch_hash"

          if [ "$master_hash" = "$branch_hash" ]; then
            git -C mlibc-base reset --hard HEAD^
          fi

      - name: Set up linux kernel headers
        run: |
          set -x
          mkdir -p linux-headers-base/{src,build}
          cp mlibc-base/ci/bootstrap.yml linux-headers-base/src/
          (
            cd linux-headers-base/build
            xbstrap init ../src
            xbstrap install linux-headers
          )
          mkdir -p linux-headers-branch/{src,build}
          cp mlibc-branch/ci/bootstrap.yml linux-headers-branch/src/
          (
            cd linux-headers-branch/build
            xbstrap init ../src
            xbstrap install linux-headers
          )
          cat > linux-headers-base/build/bootstrap-site.yml << EOF
          define_options:
            arch: ${{matrix.arch}}
          EOF
          cp linux-headers-base/build/bootstrap-site.yml linux-headers-branch/build/bootstrap-site.yml

      - name: Build and install both copies
        run: |
          set -xe
          mkdir root-base root-branch
          cat > linux-x86_64.cross-file <<-EOF
          [binaries]
          c = ['x86_64-linux-mlibc-gcc']
          cpp = ['x86_64-linux-mlibc-g++']
          
          [host_machine]
          system = 'linux'
          cpu_family = 'x86_64'
          cpu = 'x86_64'
          endian = 'little'
          EOF
          (
            cd mlibc-branch
            meson setup \
                  --cross-file=../linux-x86_64.cross-file \
                  --buildtype=debugoptimized \
                  -Dlinux_kernel_headers=$GITHUB_WORKSPACE/linux-headers-branch/build/packages/linux-headers/usr/include \
                  build
            ninja -C build
            DESTDIR="$GITHUB_WORKSPACE/root-branch" ninja -C build install
          )
          (
            cd mlibc-base
            meson setup \
                  --cross-file=../linux-x86_64.cross-file \
                  --buildtype=debugoptimized \
                  -Dlinux_kernel_headers=$GITHUB_WORKSPACE/linux-headers-branch/build/packages/linux-headers/usr/include \
                  build
            ninja -C build
            DESTDIR="$GITHUB_WORKSPACE/root-base" ninja -C build install
          )
      - name: Compare
        run: |
          # TODO(arsen): does this require handling for version suffixes?
          set -e +x
          exec 2>&1 # work around GHA foolishly decoupling stdout and stderr

          exitcode=0
          git -C mlibc-branch show -s --format=%s | grep -q abi-break || \
            exitcode=1

          echo ==== RUNNING ABIDIFF... ====
          ( cd root-base; find . -type f -name '*.so'; ) | while read -r file
          do
            if ! file -- root-{base,branch}/"$file"; then
              touch files-differ
              continue
            fi
            abidiff \
              --no-added-syms \
              --suppr mlibc-branch/ci/abidiff_suppress.ini \
              --hd1 root-base/usr/local/include/ \
              --hd2 root-branch/usr/local/include/ \
              root-{base,branch}/"$file" \
              || touch files-differ
          done

          echo ==== CHECKING FOR EXTRA FILES... ====
          ( cd root-branch; find . -type f -name '*.so'; ) | while read -r file
          do
            [ -e "root-base/$file" ] || file root-{base,branch}/"$file" \
              || touch files-differ
          done

          if [ -e files-differ ]; then
            echo SOME FILES/ABI DIFFER, SEE OUTPUT ABOVE
            exit "$exitcode"
          fi