ipywidgets fails to install in jupyterlite/demo deployment (again!)

[pierre-haessig]

On the present jupyterlite demo, there is again (see previously #97) an error when installing ipywidgets in JupyterLab when using the Pyodide kernel:

% pip install ipywidgets

The last fragment of the error message also resembles what was discussed and fixed in jupyterlite/jupyterlite#783:

ValueError: Can't find a pure Python 3 wheel for 'widgetsnbextension~=4.0.9'.

What I don't understand about this error is that it seems that there is a pure Python wheel on PyPI: https://pypi.org/project/widgetsnbextension/#files (file widgetsnbextension-4.0.9-py3-none-any.whl, uploaded 13 sept. 2023, that is yesterday)

For the reference, the relevant fragments of jupyterlite demo's requirements.txt:

# Core modules (mandatory)
jupyterlite-core==0.1.1
jupyterlab~=3.5.1

# Python kernel (optional)
jupyterlite-pyodide-kernel==0.0.10

# Python: ipywidget library for Jupyter notebooks (optional)
ipywidgets>=8.0.0,<9

However, I first caught the error with more recent versions:

# Core modules (mandatory)
jupyterlite-core==0.1.2
jupyterlab~=3.6.5

# Python kernel (optional)
jupyterlite-pyodide-kernel==0.1.1