Bug#1010797: ipywidgets: Errors when instantising widgets in Notebook - validation in Javascript fails (timeout)

[Christian Holm Christensen]

Source: ipywidgets
Version: 6.0.0-9
Severity: important
X-Debbugs-Cc: cho...@gmail.com

When trying to make an instance of a ipywidget in a notebook one get an error:

[In] from ipywidgets import *
IntSlider()

[Out] Widget Javascript not detected. It may not be installed or enabled
properly. Reconnecting the current kernel may help.

The widget _is_ displayed, though.

Looking in the Javascript Console log I see

manager.js:109 Could not cross validate the widget frontend and backend
versions. Error:
Timeout while trying to cross validate the widget frontend and backend
versions.
at manager-base.js:182:1
(anonymous) @ manager.js:109
Promise.catch (async)
(anonymous) @ manager.js:108
(anonymous) @ manager.js:116
dispatch @ jquery.min.js:2
h.handle @ jquery.min.js:2
trigger @ jquery.min.js:2
(anonymous) @ jquery.min.js:2
each @ jquery.min.js:2
each @ jquery.min.js:2
trigger @ jquery.min.js:2
events.trigger @ events.js:31
Kernel._kernel_connected @ kernel.js:424
Kernel._ws_opened @ kernel.js:530
r @ jquery.min.js:2

Investigating `manager-base.js` in the browser (packaged by webpack), suggests
that
the file `package.json` is missing from the webpack bundle, and so a there is a
timeout.

This is with a fresh 'sid' install with no external jupyter extensions or the
like.

Yours,

Christian



-- System Information:
Debian Release: bookworm/sid
APT prefers unstable
APT policy: (500, 'unstable')
Architecture: amd64 (x86_64)

Kernel: Linux 5.16.0-6-amd64 (SMP w/8 CPU threads; PREEMPT)
Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8), LANGUAGE=en_US:en
Shell: /bin/sh linked to /usr/bin/dash
Init: systemd (via /run/systemd/system)
LSM: AppArmor: enabled