wasm-demo.yml

name: WASM Demo

# Builds the self-contained WebAssembly bank GUI (examples/bank/gui_wasm) and
# publishes it to GitHub Pages under /demo/, alongside the Doxygen docs at the
# site root. Single-threaded Qt-for-WASM ⇒ no SharedArrayBuffer ⇒ no COOP/COEP
# headers ⇒ plain Pages hosting works.

on:
  push:
    branches:
      - master
    paths:
      - 'examples/bank/**'
      - 'include/morph/**'
      - '.github/workflows/wasm-demo.yml'
  pull_request:
    branches:
      - master
    paths:
      - 'examples/bank/**'
      - 'include/morph/**'
      - '.github/workflows/wasm-demo.yml'

concurrency:
  group: wasm-demo-${{ github.ref }}
  cancel-in-progress: true

permissions:
  contents: write

env:
  QT_VERSION: 6.8.3
  EMSDK_VERSION: 3.1.56   # the emscripten Qt 6.8 was built against

jobs:
  build-wasm:
    name: Build & deploy WASM demo
    runs-on: ubuntu-24.04
    steps:
      - name: Checkout
        uses: actions/checkout@v4

      - name: Install build tools
        run: |
          sudo apt-get update -q
          sudo apt-get install -y ninja-build

      # aqtinstall gives a matched host + wasm Qt pair (same cmake glue), so no
      # host/target version skew.
      - name: Install Qt (host desktop)
        uses: jurplel/install-qt-action@v4
        with:
          version: ${{ env.QT_VERSION }}
          host: linux
          target: desktop
          arch: linux_gcc_64
          dir: ${{ runner.temp }}/qt

      # Qt 6.7+ ships WebAssembly under host=all_os / target=wasm (not
      # linux/desktop). The matching host desktop Qt above provides the tools.
      - name: Install Qt (wasm, single-threaded)
        uses: jurplel/install-qt-action@v4
        with:
          version: ${{ env.QT_VERSION }}
          host: all_os
          target: wasm
          arch: wasm_singlethread
          dir: ${{ runner.temp }}/qt

      - name: Set up emsdk
        uses: mymindstorm/setup-emsdk@v14
        with:
          version: ${{ env.EMSDK_VERSION }}
          actions-cache-folder: emsdk-cache

      - name: Configure
        run: |
          export EM_CACHE="$PWD/.emcache"
          mkdir -p "$EM_CACHE"
          HOST=${{ runner.temp }}/qt/Qt/${{ env.QT_VERSION }}/gcc_64
          WASM=${{ runner.temp }}/qt/Qt/${{ env.QT_VERSION }}/wasm_singlethread
          # The all_os/wasm package extracts its scripts without the exec bit.
          chmod +x "$WASM"/bin/* || true
          # MinSizeRel: no CMAKE_BUILD_TYPE was ever set here, so every prior
          # run configured an unoptimized debug-equivalent build -- Emscripten
          # without -Os/dead-code-elimination produces a .wasm north of
          # GitHub's 100 MB Pages/repo file-size limit (108.29 MB, confirmed
          # from a real failed deploy), which the "Deploy to GitHub Pages"
          # step below has been silently failing on for every push since this
          # workflow was introduced. This is a demo bundle shipped to end
          # users over the network, not a local dev build, so MinSizeRel (not
          # Release) is the right target -- payload size matters more than
          # runtime speed here.
          "$WASM/bin/qt-cmake" -S . -B build-wasm -G Ninja \
            -DCMAKE_BUILD_TYPE=MinSizeRel \
            -DQT_HOST_PATH="$HOST" \
            -DMORPH_BUILD_EXAMPLES=ON -DMORPH_BUILD_BANK_EXAMPLE=ON \
            -DMORPH_BUILD_BANK_GUI=ON -DMORPH_BUILD_TESTS=OFF

      - name: Build
        run: |
          export EM_CACHE="$PWD/.emcache"
          cmake --build build-wasm --target bank_gui_wasm

      - name: Stage bundle
        run: |
          mkdir -p site
          BIN=build-wasm/examples/bank/gui_wasm
          cp "$BIN"/bank_gui_wasm.js "$BIN"/bank_gui_wasm.wasm "$BIN"/qtloader.js site/
          # GitHub rejects any single file over 100 MB on push (confirmed:
          # bank_gui_wasm.wasm hit 108.29 MB before this workflow set
          # CMAKE_BUILD_TYPE, silently breaking every gh-pages deploy since
          # this workflow was introduced). Fail fast here, in the build log,
          # rather than lose that signal in the deploy step's git-push error.
          ls -la site/
          WASM_BYTES=$(stat -c%s site/bank_gui_wasm.wasm)
          echo "bank_gui_wasm.wasm: $WASM_BYTES bytes"
          if [ "$WASM_BYTES" -gt 104857600 ]; then
            echo "::error::bank_gui_wasm.wasm is $WASM_BYTES bytes, over GitHub's 100 MB push limit"
            exit 1
          fi
          # Serve the Qt loader page as the directory index.
          cp "$BIN"/bank_gui_wasm.html site/index.html

      - name: Deploy to GitHub Pages (/demo)
        if: github.ref == 'refs/heads/master'
        uses: JamesIves/github-pages-deploy-action@v4
        with:
          folder: site
          target-folder: demo
          clean: false   # leave the Doxygen docs at the site root untouched