Request to update Pyodide build toolchain version

[ryanking13]

Hello from Pyodide!

We're opening this issue to request an update to the Pyodide build toolchain version used for the following package:

• duckdb

cc: @carlopi @cpcloud

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Why this is important

Pyodide has upgraded its build toolchain for packages and the runtime from (Python 3.12, Emscripten 3.1.58) to (Python 3.13, Emscripten 4.0.9).

For your packages to be included in the next Pyodide release (planned for June), they must be built with this new toolchain. Otherwise, they will not be available in Pyodide.

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Required Changes

To update your build, please make the following changes:

1. Add this line to your pyproject.toml:

   [tool.pyodide.build]
   default_cross_build_env_url = "https://github.com/pyodide/pyodide/releases/download/0.28.0a3/xbuildenv-0.28.0a3.tar.bz2"

   OR

   Pass the DEFAULT_CROSS_BUILD_ENV_URL environment variable when running pyodide build:

   DEFAULT_CROSS_BUILD_ENV_URL="https://github.com/pyodide/pyodide/releases/download/0.28.0a3/xbuildenv-0.28.0a3.tar.bz2" pyodide build

2. Upgrade the Python version used to build the package against Pyodide to 3.13.

3. If the Emscripten version is hard-coded, change it to 4.0.9.

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If you encounter any issues after making these changes, please don't hesitate to let us know.

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Update the Pyodide Distribution

Once your packages are built with the new toolchain, please create a Pull Request in pyodide/pyodide-recipes to update the package URLs.

[rgbkrk]

With duckdb/duckdb#18183 in, how close are we to resolving this @ryanking13?

[agriyakhetarpal]

Hi @RgBrk, the next step should be to host a pyodide_2025_0 wheel on a permalink somewhere and update the recipe in the pyodide-recipes repository. Thanks for getting to this!

[ryanking13]

@rgbkrk @carlopi Would you mind hosting a duckdb wheel built with the new toolchain so Pyodide can use it in our distribution?