fix: support all-None index in awkward_Index_nones_as_index.cpp

[agoose77]

This PR fixes #2768 by adding support for the all-none case to our awkward_Index_nones_as_index.cpp kernel. It also ensures that if we're argsorting the final dimension, we drop the option type from that dimension i.e. for this argsort result [10, 20, None, 5] → [3, 0, 1, 4] the array doesn't contain any None.

I think we should probably refactor this logic, but right now that's not the highest priority, so I've just patched

[codecov]

Codecov Report

Merging #2769 (d668e0c) into main (8927adb) will increase coverage by 0.00%.
The diff coverage is 100.00%.

Additional details and impacted files

Files	Coverage Δ
src/awkward/contents/indexedoptionarray.py	88.50% <100.00%> (+0.01%)	⬆️

[jpivarski]

Patching is good. The definition should also be updated here:

awkward/kernel-specification.yml

Lines 4501 to 4510 in 8927adb

	definition: |
	def awkward_Index_nones_as_index(toindex, length):
	last_index = 0
	for i in range(length):
	if toindex[i] > last_index:
	last_index = toindex[i]
	for i in range(length):
	if toindex[i] == -1:
	last_index = last_index + 1
	toindex[i] = last_index

[agoose77]

The definition should also be updated here:

Eek, nearly forgot that. Thanks.