Fix dependencies of ipywidgets #31523
Description
After #31278, which removed heavy dependencies from widgetsnbextension (which is a dependency of ipywidgets), we have to add some (lighter) dependencies to ipywidgets.
https://github.com/jupyter-widgets/ipywidgets/blob/master/setup.cfg#L35
lists:
install_requires =
ipykernel>=4.5.1
ipython>=6.1.0
traitlets>=4.3.1
nbformat>=4.2.0
widgetsnbextension~=4.0a0
jupyterlab_widgets~=2.0a0
These are not reflected in our dependency file. In this ticket we add the first three. (nbformat is only there so as to rule out some broken versions; we do not need jupyterlab_....)
So far this has not caused a build failure, but it is possible that one could appear in heavily parallelized builds.
The missing dependency is visible in the testsuite run for optional package p_group_cohomology in https://github.com/mkoeppe/sage/runs/2145415988
Running the test suite for p_group_cohomology-3.3.2...
Making check in src
Running doctests with ID 2021-03-19-18-58-47-d127e4fd.
Using --optional=debian,dochtml,meataxe,memlimit,pip,polylib,pycosat,sage,sage_spkg
Sorting sources by runtime so that slower doctests are run first....
Doctesting 13 files using 3 threads.
Traceback (most recent call last):
File "/sage/src/bin/sage-runtests", line 182, in <module>
err = DC.run()
File "/sage/local/lib/python3.9/site-packages/sage/doctest/control.py", line 1212, in run
self.run_doctests()
File "/sage/local/lib/python3.9/site-packages/sage/doctest/control.py", line 909, in run_doctests
self.dispatcher = DocTestDispatcher(self)
File "/sage/local/lib/python3.9/site-packages/sage/doctest/forker.py", line 1658, in __init__
init_sage(controller)
File "/sage/local/lib/python3.9/site-packages/sage/doctest/forker.py", line 209, in init_sage
controller.load_environment()
File "/sage/local/lib/python3.9/site-packages/sage/doctest/control.py", line 530, in load_environment
return import_module(self.options.environment)
...
File "/sage/local/lib/python3.9/site-packages/sage/repl/ipython_kernel/all_jupyter.py", line 7, in <module>
from .widgets_sagenb import (input_box, text_control, slider,
File "/sage/local/lib/python3.9/site-packages/sage/repl/ipython_kernel/widgets_sagenb.py", line 31, in <module>
from ipywidgets.widgets import (IntSlider, IntRangeSlider, FloatSlider,
File "/sage/local/lib/python3.9/site-packages/ipywidgets/__init__.py", line 25, in <module>
from .widgets import *
File "/sage/local/lib/python3.9/site-packages/ipywidgets/widgets/__init__.py", line 4, in <module>
from .widget import Widget, CallbackDispatcher, register, widget_serialization
File "/sage/local/lib/python3.9/site-packages/ipywidgets/widgets/widget.py", line 18, in <module>
from ipykernel.comm import Comm
ModuleNotFoundError: No module named 'ipykernel'
********************************************************************************
Error testing pGroupCohomology
CC: @dimpase @kliem @simon-king-jena @slel
Component: packages: standard
Author: Matthias Koeppe
Branch/Commit: 94fd11f
Reviewer: Jonathan Kliem
Issue created by migration from https://trac.sagemath.org/ticket/31523