name: wai cross-architecture byte-equality

# The `replicate` determinism contract, checked on real silicon. WAI claims its
# integer-exact decode paths (rANS entropy coder, integer fixed-point synthesis)
# produce BYTE-IDENTICAL output on every machine. This matrix proves it: five
# OS/arch combinations decode the same fixtures and assert the same golden
# bytes — rANS streams produced by CompressAI's upstream encoder, and an
# int_synth output hash produced on the reference machine (macOS arm64). One
# diverging byte anywhere fails the suite.
#
# The conformance crate (`wai/byte-exact-conformance`) #[path]-includes the
# pure-integer sources from wai-rs — no system codec libraries, no ONNX runtime
# — so every leg runs in about a minute.

on:
  pull_request:
    paths:
      - 'wai/byte-exact-conformance/**'
      - 'wai/wai-rs/src/neural/int_synth.rs'
      - 'wai/wai-rs/src/neural/jpegai_mans.rs'
      - '.github/workflows/wai-byte-equality.yml'
  push:
    branches:
      - main
    paths:
      - 'wai/byte-exact-conformance/**'
      - 'wai/wai-rs/src/neural/int_synth.rs'
      - 'wai/wai-rs/src/neural/jpegai_mans.rs'
      - '.github/workflows/wai-byte-equality.yml'

jobs:
  byte-equality:
    name: ${{ matrix.label }}
    runs-on: ${{ matrix.os }}
    strategy:
      fail-fast: false
      matrix:
        # Self-hosted fleet labels, not GitHub-hosted images. macos-x86_64 is
        # dropped: no Intel-Mac runner exists in the fleet, and by the same
        # argument the cargo-classes matrix already makes, it adds no arch
        # coverage — x86_64 is held by linux-x86_64 and windows-x86_64, arm64
        # by linux-aarch64 and the macos-arm64 reference.
        include:
          - { os: linux,       label: linux-x86_64 }
          - { os: linux-arm64, label: linux-aarch64 }
          - { os: macos,       label: macos-arm64 (reference) }
          - { os: windows,     label: windows-x86_64 }
    steps:
      - name: Checkout
        uses: actions/checkout@v4

      # Bootstrap rustup: the docker runner image ships no Rust, and
      # dtolnay/rust-toolchain cannot help — it calls `rustup`, which is absent.
      - name: Install Rust 1.97.1
        run: |
          export PATH="$HOME/.cargo/bin:$PATH"
          command -v rustup >/dev/null 2>&1 || \
            curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh -s -- -y --profile minimal --default-toolchain 1.97.1
          rustup toolchain install 1.97.1 --profile minimal
          rustup default 1.97.1
          echo "$HOME/.cargo/bin" >> "$GITHUB_PATH"

      - name: Decode fixtures, assert golden bytes
        working-directory: wai/byte-exact-conformance
        run: cargo test --release -- --nocapture