some private imports broken on main

[dcherian]

What happened?

Seen over in cf_xarray

Using xr.core.resample.Resample worked prior to #6702.

Now we need to use from xarray.core.resample import Resample

I don't know if this is something that needs to be fixed or only worked coincidentally earlier. But I thought it was worth discussing prior to release.

Thanks to @aulemahal for spotting

[aulemahal]

To add details, I suspect this commit as the culprit:
headtr1ck@cd2f2b2

It removes a direct import of the core.resample submodule in core.dataarray and moves it to the "Type checking" imports. Thus, importing xarray (import xarray as xr), does not trigger an explicit import of resample anymore.

[headtr1ck]

It was a semi-incidential change.
These modules are now only imported when required (i.e. calling DataArray.rolling ), I didn't think anyone would actually use these classes directly.

The modules can either be imported at DataArray/set module level directly again, or we could add a breaking change note.

[headtr1ck]

On the plus side, with the current implementation we probably save a few ms import time xD.

[Illviljan]

We do at least warn users that using anything from .core can change at any time,
https://xarray.pydata.org/en/stable/getting-started-guide/faq.html?highlight=private#what-parts-of-xarray-are-considered-public-api

[Illviljan]

Another example is that asfreq has moved downstream a little and is no longer available on Resample either, can probably break something as well.

The docstring also warns to use this class directly since it behaves as an incomplete base class.

xarray/xarray/core/resample.py

Lines 20 to 24 in 725258e

	"""An object that extends the `GroupBy` object with additional logic
	for handling specialized re-sampling operations.
	You should create a `Resample` object by using the `DataArray.resample` or
	`Dataset.resample` methods. The dimension along re-sampling

[headtr1ck]

Another example is that asfreq has moved downstream a little and is no longer available on Resample either, can probably break something as well.

It was moved because it actually didn't work in the baseclass ;)
So I don't think anyone has ever used that.