Pin to Dask 2021.02.0 while incompatibility with later versions is investigated

[tomwhite]

No description provided.

[tomwhite]

This will fix the main build and the documentation build (see #482).

[jeromekelleher]

Are we sure we want to pin in setup.cfg? This does more than just fix the CI builds, doesn't it?

[tomwhite]

Are we sure we want to pin in setup.cfg? This does more than just fix the CI builds, doesn't it?

You're right. I was hoping this pin would be short-lived, and certainly wouldn't get released.

I can just change the requirements file though for CI.

[jeromekelleher]

You're right. I was hoping this pin would be short-lived, and certainly wouldn't get released.

Pins have a habit of persisting, I'd rather keep it to a minimum, but it's up to you really.

[jrbourbeau]

I'd be curious to know what changes in the Dask 2021.03.0 release impacted sgkit (apologies for any unexpected breakages)

[tomwhite]

I'd be curious to know what changes in the Dask 2021.03.0 release impacted sgkit (apologies for any unexpected breakages)

It was this Dask PR: dask/dask#6738. I see the problem described in #482 with that commit, but not with the one before it.

More concretely, the following prints array(3) with that Dask PR, and just 3 with previous versions.

importnumpyasnpimportxarrayasxrimportdask.arrayasdaxr.DataArray.__module__="xarray"# simulate sphinx workaround, which has the effect of Dask not recognising it as xarraydata=np.arange(4)
da.asarray(xr.DataArray(data)).max().compute()

[jrbourbeau]

Gotcha, thanks for the upstream PR in Dask!