Pyodide support

[anthrotype]

• Detect Emscripten cross-compilation in setup.py, skipping platform-specific sources (CoreText, DirectWrite, Uniscribe)
• Add build-pyodide job to CI workflow
• Upload Pyodide wheel to GitHub releases only (PyPI doesn't accept wasm32 wheels yet, see Add support for wasm32 platform pypi/warehouse#10416 and https://discuss.python.org/t/pep-783-emscripten-packaging)
• Also add tox -e pyodide for local build and test

Fixes #270

[behdad]

I think harfbuzz.cc has all these files automatically included.

[anthrotype]

but harfbuzz.cc lacks the subset module..

[behdad]

Right. That's annoying.

[anthrotype]

@Vipitis the CI finally built some pyodide wheels for uharfbuzz here: https://github.com/harfbuzz/uharfbuzz/actions/runs/20712353445/artifacts/5023130791

Would you like to give them a go? The uharfuzz own tests do pass when run inside a pyodide venv, like cibuildwheel does.

[Vipitis]

hey @anthrotype thanks a lot for figuring this out.

I obtained the wheel yesterday already from your branch and now also from the ci artifacts. The latter has the wrong version number (0.1) which could be a problem for others.
Both wheels work, but I can't test much functionality at the moment since I found additional hurdles apart from uharfbuzz that I will need to look into before our examples run in the browser.

[anthrotype]

thanks for checking. the version number is expected, only when we push a tagged commit to do an actual release we do a full clone and "unshallow" the repository so the correnct version string is obtained from git. The 0.1 is setuptools-scm failing to get a proper tag.

[khaledhosny]

Is there anything blocking this?

[anthrotype]

I was waiting for them to test if these actually work.. the tests pass, so feel free to merge

[khaledhosny]

Uploading the Pyodide wheels seems to fail: https://github.com/harfbuzz/uharfbuzz/actions/runs/23300214344/job/67760947291

Run if [ -d dist-pyodide ] && [ "$(ls -A dist-pyodide)" ]; then
  if [ -d dist-pyodide ] && [ "$(ls -A dist-pyodide)" ]; then
    gh release upload refs/tags/v0.53.4 dist-pyodide/*.whl
  fi
  shell: /usr/bin/bash -e {0}
  env:
    GH_TOKEN: ***
    pythonLocation: /opt/hostedtoolcache/Python/3.14.3/x64
    PKG_CONFIG_PATH: /opt/hostedtoolcache/Python/3.14.3/x64/lib/pkgconfig
    Python_ROOT_DIR: /opt/hostedtoolcache/Python/3.14.3/x64
    Python2_ROOT_DIR: /opt/hostedtoolcache/Python/3.14.3/x64
    Python3_ROOT_DIR: /opt/hostedtoolcache/Python/3.14.3/x64
    LD_LIBRARY_PATH: /opt/hostedtoolcache/Python/3.14.3/x64/lib
    RELEASE_NAME: 0.53.4
    IS_PRERELEASE: false
release not found

[anthrotype]

You can't upload to PyPI yet I think, they aren't sufficiently standardised IIRC. I am at a conference right now and can't check, but I believe the path forward for now would be to disable the automatic upload for those and perhaps make them available only as GitHub Release downloadable assets

[anthrotype]

Oh now I remember I had written about that (see above here)

Upload Pyodide wheel to GitHub releases only (PyPI doesn't accept wasm32 wheels yet, see Add support for wasm32 platform pypi/warehouse#10416 and https://discuss.python.org/t/pep-783-emscripten-packaging)

[anthrotype]

Oh! It's the GH assets upload that it's failing (not PyPI), sorry I hadn't read it carefully. Ok not sure. Next thing to check, is the GitHub token used enabled for "write"?

[Vipitis]

I was waiting for them to test if these actually work.. the tests pass, so feel free to merge

sorry for missing this. Best I can tell harfbuzz and shaping works on pyodide. (I didn't get to implement glyph rendering, but that isn't using harfbuzz yet).