Atomnames methods should handle empty group #2879

[kainszs]

Fixes #2879

Changes made in this Pull Request:

• the methods psi_selections(), omega_selections(), chi1_selections() can handle empty groups

NOTE: Since the methods return by default a list of atom groups, the methods will also return an empty list in the case of empty residues instead of an empty residue group ask in the issue. If you accept the code for the change, I will add comments, the tests and update the CHANGELOG.

Update:

I just realized that I accidentally formatted with black when saving. Should I just push the file again that only contains my changes and reopen the PR?

PR Checklist

• Tests?
• Docs?
• CHANGELOG updated?
• Issue raised/referenced?

Developers certificate of origin

• I certify that this contribution is covered by the LGPLv2.1+ license as defined in our LICENSE and adheres to the Developer Certificate of Origin.

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📚 Documentation preview 📚: https://mdanalysis--4528.org.readthedocs.build/en/4528/

[pep8speaks]

Hello @kainszs! Thanks for opening this PR. We checked the lines you've touched for PEP 8 issues, and found:

• In the file package/MDAnalysis/core/topologyattrs.py:

Line 402:80: E501 line too long (85 > 79 characters)
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Line 3326:80: E501 line too long (85 > 79 characters)

[github-actions]

Hello there first time contributor! Welcome to the MDAnalysis community! We ask that all contributors abide by our Code of Conduct and that first time contributors introduce themselves on GitHub Discussions so we can get to know you. You can learn more about participating here. Please also add yourself to package/AUTHORS as part of this PR.

[github-actions]

Linter Bot Results:

Hi @kainszs! Thanks for making this PR. We linted your code and found the following:

Some issues were found with the formatting of your code.

Code Location	Outcome
main package	⚠️ Possible failure
testsuite	✅ Passed

Please have a look at the darker-main-code and darker-test-code steps here for more details: https://github.com/MDAnalysis/mdanalysis/actions/runs/8409848854/job/23027625925

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Please note: The black linter is purely informational, you can safely ignore these outcomes if there are no flake8 failures!

[codecov]

Codecov Report

Attention: Patch coverage is 96.96970% with 9 lines in your changes are missing coverage. Please review.

Project coverage is 93.60%. Comparing base (0582265) to head (030798c).

Files	Patch %	Lines
package/MDAnalysis/core/topologyattrs.py	96.96%	6 Missing and 3 partials ⚠️

Additional details and impacted files

@@             Coverage Diff             @@
##           develop    #4528      +/-   ##
===========================================
- Coverage    93.65%   93.60%   -0.05%     
===========================================
  Files          168      180      +12     
  Lines        21215    22300    +1085     
  Branches      3908     3911       +3     
===========================================
+ Hits         19869    20875    +1006     
- Misses         888      964      +76     
- Partials       458      461       +3     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[RMeli]

Hi @kainszs, thank you for your contribution.

I just realized that I accidentally formatted with black when saving. Should I just push the file again that only contains my changes and reopen the PR?

Yes please. There is an ongoing discussion to format with black (see #2450), but for PR we require to only format the lines you change, otherwise a review is nearly impossible (too many unrelated changes).