Creating empty packages results in unguided errors about nlmod

[bdestombe]

Currently, I have in my modelscripts the following code. It works, is not pretty and not intuitively implented by the end-user.

if cnc.stress_period_data.data is None:
    gwt.remove_package(cnc.name[0])

[dbrakenhoff]

Checking for zero length stress_period_data makes sense to me. The least we should do is log a warning, but I think it also makes sense to prevent the package from being added/created in that situation.

[bdestombe]

Thus using the example of the initiation of the CNC package:

    cnc = nlmod.gwt.cnc(
        ds,
        gwt,
        da_mask=(ds["northsea"] == 1).expand_dims({"layer": [ds.layer.data[0]]}),
        da_conc=ds["chloride"].isel(layer=slice(0, 1)),
    )

this code produce a zero-length stress_period_data because idomain, stored in ds, is false for all relevant cells.

Running this line of code should:

• Not raise an error
• Add a warning to the log that the package will not be added to the simulation because there is no stress_period_data
• Do not add the package to gwt
• Return None