(fix): subsetting with empty list

[ilan-gold]

• Closes Subsetting w/ empty list when X is dense throws error #1149
• Tests added
• Release note added (or unnecessary)

[codecov]

Codecov Report

Merging #1243 (9fb9f33) into main (ff69d1e) will decrease coverage by 33.20%.
The diff coverage is 0.00%.

Additional details and impacted files

@@             Coverage Diff             @@
##             main    #1243       +/-   ##
===========================================
- Coverage   85.27%   52.07%   -33.20%     
===========================================
  Files          34       34               
  Lines        5404     5413        +9     
===========================================
- Hits         4608     2819     -1789     
- Misses        796     2594     +1798     

Flag	Coverage Δ
gpu-tests	52.07% <0.00%> (-0.13%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Files	Coverage Δ
anndata/_core/index.py	59.47% <0.00%> (-32.89%)	⬇️

... and 23 files with indirect coverage changes

[flying-sheep]

So the idea is that if people want this fast, they should pass an array in the first place, I guess.

Maybe the error message should be more friendly?

[ilan-gold]

@flying-sheep So you're saying we should catch the error and then report back that the data types are mixed? Just a side note, this behavior of mixed types doesn't seem to work so this would not be a regression:

from anndata.tests.helpers import gen_adata
adata = gen_adata((100, 100))
adata[[0, 2], :] # good
adata[['cell5'], :] # good
adata[[0, 2, 'cell5'], :] # bad

[flying-sheep]

Since we add custom handling here, raising a custom error (KeyError?) would be a nice thing to tell users what they’re doing wrong.

[ilan-gold]

Sounds good @flying-sheep

[flying-sheep]

why no release note?

[ilan-gold]

I guess I didn't know what qualified as "unnecessary" for a release note and this seemed like one of those things.

[flying-sheep]

Hmm, guess if that's not in the contribution guide we should add it, and if it is, we should link it.

As far as I understand, release notes are not encouraged if an unreleased feature gets modified or if the change is purely development process focused (tests, doc building, ...). This is a bugfix to a live feature, so it should get a release note.