List models that were found on get_model failure

[paddymul]

I am having a lot of trouble with a variety of problem developing a jupyter/ipywidget widget with custom typescript. Especially around packaging. I frequently run into problems with "module/model not found". I have tracked it down to this method:

ipywidgets/packages/base-manager/src/manager-base.ts

Line 217 in 6f6156c

async get_model(model_id: string): Promise<WidgetModel> {

It would be very helpful if instead of just saying "widget model not found", the whole contents of this._models was listed. That way you'd have a better chance of figuring out what model or module name your extension did register and adjust your build accordingly.

Other related issues
jupyterlab/hatch-jupyter-builder#112
jupyter-widgets/widget-ts-cookiecutter#131

Thanks,
Paddy

[maartenbreddels]

Might be good to pick up at the jupytercon sprint?
I agree, we can do much better with error messages.