In docs.yml, "Build C++ WASM" fails with ninja not found

[jpivarski]

For example, in this: https://github.com/scikit-hep/awkward/actions/runs/12188354714/job/34002123054

The failing log is:

Run # pyodide-build doesn't work out of the box with pipx
  # pyodide-build doesn't work out of the box with pipx
  CFLAGS=-fexceptions LDFLAGS=-fexceptions pyodide build --exports whole_archive
  shell: /usr/bin/bash -e {0}
  env:
    X86_64_PYTHON_VERSION: 3.11.0
    SOURCE_DATE_EPOCH: 1668811[2](https://github.com/scikit-hep/awkward/actions/runs/12188354714/job/34002123054#step:9:2)11
    pythonLocation: /opt/hostedtoolcache/Python/3.11.2/x64
    PKG_CONFIG_PATH: /opt/hostedtoolcache/Python/[3](https://github.com/scikit-hep/awkward/actions/runs/12188354714/job/34002123054#step:9:3).11.2/x64/lib/pkgconfig
    Python_ROOT_DIR: /opt/hostedtoolcache/Python/3.11.2/x6[4](https://github.com/scikit-hep/awkward/actions/runs/12188354714/job/34002123054#step:9:4)
    Python2_ROOT_DIR: /opt/hostedtoolcache/Python/3.11.2/x64
    Python3_ROOT_DIR: /opt/hostedtoolcache/Python/3.11.2/x64
    LD_LIBRARY_PATH: /opt/hostedtoolcache/Python/3.11.2/x64/lib
    PATH: /home/runner/work/_temp/[5](https://github.com/scikit-hep/awkward/actions/runs/12188354714/job/34002123054#step:9:5)5485d84-5b5a-4[6](https://github.com/scikit-hep/awkward/actions/runs/12188354714/job/34002123054#step:9:6)3f-b5b9-a3a3e161e9e8/emsdk-main:/home/runner/work/_temp/55485d84-5b5a-463f-b5b9-a3a3e161e9e8/emsdk-main/upstream/emscripten:/opt/hostedtoolcache/Python/3.11.2/x64/bin:/opt/hostedtoolcache/Python/3.11.2/x64:/snap/bin:/home/runner/.local/bin:/opt/pipx_bin:/home/runner/.cargo/bin:/home/runner/.config/composer/vendor/bin:/usr/local/.ghcup/bin:/home/runner/.dotnet/tools:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games
    EMSDK: /home/runner/work/_temp/55485d84-5b5a-463f-b5b9-a3a3e161e9e8/emsdk-main
    EMSDK_NODE: /home/runner/work/_temp/55485d84-5b5a-463f-b5b9-a3a3e161e9e8/emsdk-main/node/20.18.0_64bit/bin/node
  
*** scikit-build-core 0.10.[7](https://github.com/scikit-hep/awkward/actions/runs/12188354714/job/34002123054#step:9:7) using CMake 3.31.1 (wheel)
*** Configuring CMake...
configure: cmake -DCMAKE_C_COMPILER=/tmp/tmpkwce4mjl/cc -DCMAKE_CXX_COMPILER=/tmp/tmpkwce4mjl/c++ -DCMAKE_AR=/tmp/tmpkwce4mjl/ar -DCMAKE_C_COMPILER_AR=/tmp/tmpkwce4mjl/ar -DCMAKE_CXX_COMPILER_AR=/tmp/tmpkwce4mjl/ar --fresh -S. -Bbuild/cpython-311 -DCMAKE_BUILD_TYPE:STRING=Release -Cbuild/cpython-311/CMakeInit.txt -DCMAKE_INSTALL_PREFIX=/tmp/tmpn02_aikz/wheel/platlib -DCMAKE_MAKE_PROGRAM=ninja -DCMAKE_CROSSCOMPILING_EMULATOR=/home/runner/work/_temp/554[8](https://github.com/scikit-hep/awkward/actions/runs/12188354714/job/34002123054#step:9:8)5d84-5b5a-463f-b5b9-a3a3e161e9e8/emsdk-main/node/20.18.0_64bit/bin/node
loading initial cache file build/cpython-311/CMakeInit.txt
CMake Error at CMakeLists.txt:6 (project):
  Running
   'ninja' '--version'
  failed with:
   no such file or directory
-- Configuring incomplete, errors occurred!
emcmake: error: 'cmake -DCMAKE_C_COMPILER=/tmp/tmpkwce4mjl/cc -DCMAKE_CXX_COMPILER=/tmp/tmpkwce4mjl/c++ -DCMAKE_AR=/tmp/tmpkwce4mjl/ar -DCMAKE_C_COMPILER_AR=/tmp/tmpkwce4mjl/ar -DCMAKE_CXX_COMPILER_AR=/tmp/tmpkwce4mjl/ar --fresh -S. -Bbuild/cpython-311 -DCMAKE_BUILD_TYPE:STRING=Release -Cbuild/cpython-311/CMakeInit.txt -DCMAKE_INSTALL_PREFIX=/tmp/tmpn02_aikz/wheel/platlib -DCMAKE_MAKE_PROGRAM=ninja -DCMAKE_CROSSCOMPILING_EMULATOR=/home/runner/work/_temp/55485d84-5b5a-463f-b5b[9](https://github.com/scikit-hep/awkward/actions/runs/12188354714/job/34002123054#step:9:9)-a3a3e161e9e8/emsdk-main/node/20.18.0_64bit/bin/node' failed (returned 1)
*** CMake configuration failed
* Creating virtualenv isolated environment...
* Installing packages in isolated environment... (pybind11, scikit-build-core>=0.[10](https://github.com/scikit-hep/awkward/actions/runs/12188354714/job/34002123054#step:9:10))
* Getting dependencies for wheel...
* Installing packages in isolated environment... (ninja>=1.5)
* Building wheel...
ERROR Backend subproccess exited when trying to invoke build_wheel
Error: Process completed with exit code 1.

and it was configured somewhere in

awkward/.github/workflows/docs.yml

Lines 61 to 118 in 661702b

	awkward-cpp-wasm:
	name: Build C++ WASM
	runs-on: ubuntu-22.04
	needs: [pyodide-python-version]
	steps:
	- uses: actions/checkout@v4
	with:
	submodules: true
	- name: Setup Python
	uses: actions/setup-python@v5
	with:
	python-version: "${{ needs.pyodide-python-version.outputs.python-version }}"
	- name: Generate build files
	run: pipx run nox -s prepare -- --headers --signatures
	- name: Cache wheel
	id: cache-awkward-cpp-wasm-wheel
	uses: actions/cache@v4
	with:
	path: ./awkward-cpp/dist
	key: ${{ runner.os }}-"${{ needs.pyodide-python-version.outputs.python-version }}-awkward-cpp-wasm-${{ hashFiles('awkward-cpp/**') }}
	- name: Install dependencies
	if: steps.cache-awkward-cpp-wasm-wheel.outputs.cache-hit != 'true'
	run: python3 -m pip install -r docs/requirements-wasm.txt
	- name: Determine EMSDK version
	if: steps.cache-awkward-cpp-wasm-wheel.outputs.cache-hit != 'true'
	id: compute-emsdk-version
	run: |
	# Prepare xbuild environment (side-effect)
	pyodide config list
	# Save EMSDK version
	EMSCRIPTEN_VERSION=$(pyodide config get emscripten_version)
	echo "emsdk-version=$EMSCRIPTEN_VERSION" >> $GITHUB_OUTPUT
	working-directory: awkward-cpp
	- name: Install EMSDK
	uses: mymindstorm/setup-emsdk@v14
	if: steps.cache-awkward-cpp-wasm-wheel.outputs.cache-hit != 'true'
	with:
	version: ${{ steps.compute-emsdk-version.outputs.emsdk-version }}
	- name: Build wheel
	if: steps.cache-awkward-cpp-wasm-wheel.outputs.cache-hit != 'true'
	id: build-awkward-cpp-wasm-wheel
	run: |
	# pyodide-build doesn't work out of the box with pipx
	CFLAGS=-fexceptions LDFLAGS=-fexceptions pyodide build --exports whole_archive
	working-directory: awkward-cpp
	- name: Upload wheel
	uses: actions/upload-artifact@v4
	with:
	name: awkward-cpp-wasm
	path: awkward-cpp/dist/awkward*wasm32.whl

I think it's failing specifically on

awkward/.github/workflows/docs.yml

Line 111 in 661702b

CFLAGS=-fexceptions LDFLAGS=-fexceptions pyodide build --exports whole_archive

so pyodide build. Is this a change in Pyodide? Does it now need Ninja to be installed, and would that be easy to add?

[agoose77]

@jpivarski Ninja should be added by scikit-build-core, unless it's not available on the platform.

However, this machinery was added so that we can deploy the latest version of Awkward Array in docs, with a JupyterLite distribution.

It looks like you removed that functionality, and I just loaded the /lite API path and found it doesn't work. So, if you're not interested in this functionality and shipping JupyterLite, then the quickest fix is just remove any logic pertaining to building of WASM wheels in CI!

[jpivarski]

That's right! I thought this was here as a test of WASM-building, but that's #3270. In that case, I'll just remove this block. Thanks!