Breakages with changes to xarray's internals during the NamedArray refactor

[TomNicholas]

So far datatree appears to have got away with cheekily importing and using many private xarray internals, but soon things will start breaking.

@andersy005 is hard at work refactoring xarray to split out the internal Variable class as a new stand-alone object, NamedArray.

These changes will definitely break datatree at some point soon, if only because private xarray utility functions will be imported from different places within xarray's codebase.

The long-term solution to this is to get on with integrating everything in datatree into xarray upstream. In the short-term we probably do not want to try and do that integration until the NamedArray refactor has progressed further, so there will be at least some versions of xarray for which datatree breaks (probably the next xarray version to be released).

[Illviljan]

How about pinning xarray to a working version and making a quick release?

[TomNicholas]

Okay this anticipated issue seems to have now manifested.

How about pinning xarray to a working version and making a quick release?

Seems like a good idea.