Why is `Array.name` nullable?

[d-v-b]

The name of an array can be None, which is a bit odd since None is not a valid location in a file system. Can someone explain what we are expressing by allowing Array.name to be None? Note that this is carried over from v2, and the docstring references h5py.

zarr-python/src/zarr/core/array.py

Lines 813 to 827 in d6508b5

	def name(self) -> str | None:
	"""Array name following h5py convention.
	Returns
	-------
	str
	The name of the array.
	"""
	if self.path:
	# follow h5py convention: add leading slash
	name = self.path
	if name[0] != "/":
	name = "/" + name
	return name
	return None

[d-v-b]

My next question is, what would we lose by using the empty string '' instead of None for this case?

[d-v-b]

I did some quick research and apparently in hdf5, the name of a dataset or a group can be NULL if the array / group is an anonymous group, i.e. a group / dataset has not been added to an extant hierarchy, otherwise it should be a string. We have never supported this in zarr-python, So I don't think zarr-python v2 was correctly modelling hdf5's semantics here, and I don't think we should continue to incorrectly model hdf5.

see #2499

[jhamman]

closed by #2499