[Debian-science-sagemath] Sage 7.6

[Tobias Hansen]

Thanks for the overview. It's more involved than I expected.

> Does sagemath have a hard dependency on updating these packages?
> 

The doc build of sage now produces errors because it's missing
ValueWidget, which is new in ipywidgets 6 I think.

And there are a bunch of failing doctests with our current packages:
sage -t --long src/sage/repl/ipython_kernel/interact.py  # 30 doctests
failed
sage -t --long src/sage/repl/ipython_kernel/widgets.py  # 79 doctests failed
sage -t --long src/sage/repl/ipython_kernel/widgets_sagenb.py  # 76
doctests failed
sage -t --long src/sage/repl/ipython_extension.py  # 1 doctest failed

I'll focus on the floating point exceptions first. Once that's fixed, if
we want to make it work with the old jupyter packages, we would have to
track down the sagemath tickets that updated jupyter and reverse-apply
these patches.

Best,
Tobias