Installation: Class null not found in module @jupyter-widgets/controls

[PierreNowak]

Hello !

I am struggling at installing ipyannotations on jupyterlab.

The widget loads and I can draw polygons but it doesn't save anything into widget.data.

Here is a dump of python packages/labextensions:

    JupyterLab v3.5.0
    /opt/conda/share/jupyter/labextensions
            jupyterlab_pygments v0.2.2 enabled OK (python, jupyterlab_pygments)
            ipycanvas v0.13.1 enabled OK
            ipyannotations v0.4.2 enabled OK (python, ipyannotations)
            ipyevents v2.0.1 enabled OK
            jupyter-matplotlib v0.11.2 enabled OK
            @jupyter-widgets/jupyterlab-manager v5.0.3 enabled OK (python, jupyterlab_widgets)
    
    Other labextensions (built into JupyterLab)
       app dir: /opt/conda/share/jupyter/lab
    
    (base) jovyan@pierre:~/work$ pip freeze|grep ipy
    brotlipy @ file:///home/conda/feedstock_root/build_artifacts/brotlipy_1666764671472/work
    certipy==0.1.3
    ipyannotations==0.5.1
    ipycanvas==0.13.1
    ipyevents==2.0.1
    ipykernel @ file:///home/conda/feedstock_root/build_artifacts/ipykernel_1668027051105/work
    ipympl==0.9.2
    ipython @ file:///home/conda/feedstock_root/build_artifacts/ipython_1667140637743/work
    ipython-genutils==0.2.0
    ipywidgets==8.0.2

I tried to downgrade ipywidgets to 7.7.2 but then I have to downgrade in cascade every other package and can't make it work.

thanks

[janfreyberg]

Thank you for raising this - this issue is pretty confusing to me as the code has obviously been static for a while, and as far as I know javascript dependencies are pinned, although maybe not strictly enough.

I'll look into this ASAP but any help would be appreciated. The same issue is raised in #33

[ryukinix]

I'm experiencing this here... using jupyter-lab:

[Open Browser Console for more detailed log - Double click to close this message]
Failed to load view class 'null' from module '@jupyter-widgets/controls'
Error: Class null not found in module @jupyter-widgets/controls
    at f.loadClass (http://localhost:8888/lab/extensions/@jupyter-widgets/jupyterlab-manager/static/134.a63a8d293fb35a52dc25.js?v=a63a8d293fb35a52dc25:1:75244)
    at async f.loadViewClass (http://localhost:8888/lab/extensions/@jupyter-widgets/jupyterlab-manager/static/336.ebc7a55ea1768712771f.js?v=ebc7a55ea1768712771f:1:10958)
    at async http://localhost:8888/lab/extensions/@jupyter-widgets/jupyterlab-manager/static/336.ebc7a55ea1768712771f.js?v=ebc7a55ea1768712771f:1:2808
    at async Promise.all (index 0)

I tried to downgrade ipywidgets to 7.7.2 but then I have to downgrade in cascade every other package and can't make it work.

I tried this too, but the resolver package entered in loop.

[wl2776]

I am experiencing the same error.
Is there any workaround / solution?