KeyError: "no index found for coordinate 'layer'"

[vincentpost]

When running nlmod.to_model_ds(...) the following error occurs when xarray version 2025.4.0 is installed: KeyError: "no index found for coordinate 'layer'" The error does not occur with xarray version 2024.6.0. The error is thrown by the remove_inactive_layers method

nlmod/nlmod/dims/layers.py

Line 1386 in 3bd6965

ds = ds.sel(layer=(idomain > 0).any(idomain.dims[1:]))

but the cause lies somewhere else. I traced it down to the interp method used here:

nlmod/nlmod/dims/resample.py

Line 166 in 3bd6965

ds_out = ds_in.interp(

Somewhere between xarray versions 2024.6.0 and 2025.4.0 the behaviour of this method must have changed: In the newer xarray version 'layer' is dropped from the DataSet's indexes attribute (causing the KeyError later down the track in remove_inactive_layers), in the older version it remains preserved.

Has anyone seen this before? Not sure what the best solution is (other than using an older xarray version).

Thanks,
Vincent

[dbrakenhoff]

Thanks for reporting this, and putting in the effort to track down the bug! I'll take a look today :)