remove widget.register

[ianhi]

As discussed in the Feb 18, 2021 meeting the default for widgets should be to not register themselves with widgets.register

So this will need to be removed:

widget-cookiecutter/{{cookiecutter.github_project_name}}/{{cookiecutter.python_package_name}}/example.py

Line 6 in de21c0f

@widgets.register

and then I think there will need to be an _frontend.py file like in the ts-cookiecutter

[vidartf]

For those not in the meeting, would anyone care to summarize the reasoning behind when something should be registered and why (not)?

[ianhi]

For those not in the meeting, would anyone care to summarize the reasoning behind when something should be registered and why (not)?

woops that's definitely something I meant to include in this issue 😬

My understanding is that calling widgets.register on the widget will allow the typescript side to create a widget, otherwise the kernel has no way of knowing what to do with the comm it receives. The argument is that this should not be the default because it introduces a potential security risk (and maybe was a problem in voila??). So widgets.register should be treated as an advanced use case and not part of the default setup.

That was a paraphrase of what @maartenbreddels said, so I may have gotten some details wrong but I think that's the gist.

(and also documented: see jupyter-widgets/ipywidgets#3134)