get_points_in_sphere() has inconsistent return types

[fxcoudert]

Python version

3.11.5

Pymatgen version

2024.4.13

Operating system version

No response

Current behavior

When get_points_in_sphere() is called with zip_results=False, it returns a tuple of numpy arrays:

            return frac_coords, distances, indices, images

However, if it found no point in the requested radius, then… the return type changes:

                return [] if zip_results else [()] * 4

So now it's returning four empty tuples. It is very surprising to the use, because using numpy functions of those will raise a type error. For example, I was doing things like np.any(distances < 1.0): that would work perfectly as expected with an empty numpy array, but will crash with an empty tuple.

Expected Behavior

I don't see what is gained by returning () instead of np.array([]) and it would be less surprising to users (I just spent half an hour understanding this weird behavior).

Minimal example

No response

Relevant files to reproduce this bug

No response

[janosh]

@fxcoudert thanks for reporting! will be fixed by #3797