Distributed: Bokeh RC Updates Breaks Dashboard

[quasiben]

In bokeh 2.3.0rc2, there are some issues with Dask dashboard documented here:
https://github.com/bokeh/bokeh/issues/10935

While Bokeh updates to handle nullables for a variety of objects dask could update the null calls within Bokeh

Setting None in x_range:
https://github.com/dask/distributed/blob/383ea0326ae103b5d5e0b62ed9c3cb18510c5b9e/distributed/dashboard/components/scheduler.py#L867-L874

This could be set to 100 which we do in the update:
https://github.com/dask/distributed/blob/383ea0326ae103b5d5e0b62ed9c3cb18510c5b9e/distributed/dashboard/components/scheduler.py#L994

We also have a None in the Profile plot selector:
https://github.com/dask/distributed/blob/383ea0326ae103b5d5e0b62ed9c3cb18510c5b9e/distributed/dashboard/components/shared.py#L277

I believe the defaults here is `['All', None]

[bryevdv]

AFAIK the code above would fail to render initially, but the raised error was not critical, and things "worked" in the sense that a later update to meaningful values later allowed subsequent renders to succeed. We will make some temporary easements to strict nullability now to prevent immediate breakage for Dask users, but it would certainly be good to update these on your end as soon as is practical.

[bryevdv]

https://github.com/bokeh/bokeh/issues/10935 is merged and part of 2.3.0rc3 which is available via

conda install -c bokeh/c/dev bokeh=2.3.0rc3

Would be really great if someone on the the dask side could check it out and give a 👍 (we would like to release tomorrow)

As an aside one reason this was not uncovered earlier is that the downstream test job was replacing the dev package with the latest release by mistake. That has also been resolved (and all unit tests are passing with the dev package)

[bryevdv]

I followed the steps outlined here: https://github.com/bokeh/bokeh/issues/10935#issuecomment-783835213 and there seems to be one issue, with the task graph, so we will plan to postpone a day until it can be resolved.

[jakirkham]

This was fixed right?

[quasiben]

Fixed on the bokeh side but I still plan change the xrange and select defaults