Pyodide support by anthrotype · Pull Request #275 · harfbuzz/uharfbuzz

anthrotype · 2026-01-02T19:09:52Z

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

- 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 pypi/warehouse#10416) Fixes #270

behdad · 2026-01-02T19:11:41Z

setup.py

+        define_macros.append(("HAVE_DIRECTWRITE", "1"))
+        define_macros.append(("HAVE_UNISCRIBE", "1"))
+        libraries += ["usp10", "gdi32", "user32", "rpcrt4", "dwrite"]
+        sources += [


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

but harfbuzz.cc lacks the subset module..

Right. That's annoying.

Pyodide doesn't support Python 3.14 yet, so we need to use 3.13 explicitly instead of '3.x' which resolves to the latest.

Remove redundant test step - cibuildwheel already runs tests via test-command for each wheel it builds.

anthrotype · 2026-01-05T10:29:14Z

@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 · 2026-01-05T16:28:09Z

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 · 2026-01-05T16:30:37Z

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 · 2026-03-17T12:19:36Z

Is there anything blocking this?

anthrotype · 2026-03-17T13:32:03Z

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

khaledhosny · 2026-03-19T14:52:04Z

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 · 2026-03-19T15:00:05Z

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 · 2026-03-19T15:01:01Z

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 · 2026-03-19T15:02:25Z

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"?

anthrotype · 2026-03-19T15:19:49Z

.github/workflows/ci.yml

+    - name: Upload Pyodide wheel to GitHub release
+      run: |
+        if [ -d dist-pyodide ] && [ "$(ls -A dist-pyodide)" ]; then
+          gh release upload ${{ github.ref }} dist-pyodide/*.whl


@khaledhosny i think the issue is this is supposed to be github.ref_name ("v0.53.4") instead of github.ref ("refs/tags/v0.53.4").
And for consistency also the gh release create call right above this (which somehow normalises ref to ref_name internally, whereas upload command doesn't).

since we'll have to re-tag, the release that was created will have to be deleted as well

anthrotype added 2 commits January 2, 2026 18:34

Add tox -e pyodide for local build and test

b482b15

anthrotype changed the title ~~Pyodide~~ Pyodide support Jan 2, 2026

behdad reviewed Jan 2, 2026

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anthrotype mentioned this pull request Jan 2, 2026

Pyodide compatibility? #270

Closed

Fix Pyodide CI: pin Python to 3.13

938a4e0

Pyodide doesn't support Python 3.14 yet, so we need to use 3.13 explicitly instead of '3.x' which resolves to the latest.

anthrotype force-pushed the pyodide branch from 0fec1d6 to aeb80e4 Compare January 5, 2026 10:08

Fix Pyodide CI: use cibuildwheel's built-in test runner

4eebcec

Remove redundant test step - cibuildwheel already runs tests via test-command for each wheel it builds.

anthrotype force-pushed the pyodide branch from aeb80e4 to 4eebcec Compare January 5, 2026 10:22

This was referenced Feb 10, 2026

[WIP] js_webgpu backend prototype pygfx/wgpu-py#753

Draft

Pyodide compatibility [preview] pygfx/pygfx#1273

Draft

khaledhosny merged commit 9c2d0f7 into main Mar 17, 2026
7 checks passed

khaledhosny deleted the pyodide branch March 17, 2026 13:33

anthrotype commented Mar 19, 2026

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