[core][scheduler] Fix iterator invalidation in node label filtering

[RocMarshal]

Thank you for contributing to Ray! 🚀
Please review the Ray Contribution Guide before opening a pull request.

⚠️ Remove these instructions before submitting your PR.

💡 Tip: Mark as draft if you want early feedback, or ready for review when it's complete.

Description

[core][scheduler] Fix iterator invalidation in node label filtering

Related issues

#65517

Additional information

N.A

[gemini-code-assist]

Code Review

This pull request fixes an iterator invalidation bug in NodeLabelSchedulingPolicy::FilterNodesByLabelMatchExpressions when erasing elements from match_nodes during iteration, and adds a corresponding unit test. The reviewer suggested a more idiomatic way to erase elements from the map by utilizing the return value of erase instead of manually copying and incrementing the iterator.

[gemini-code-assist]

Instead of manually copying the iterator, incrementing it, and then erasing the copy, you can use the return value of match_nodes.erase(iter). In absl::flat_hash_map (and standard C++11 containers), erase returns the iterator pointing to the element immediately following the erased element. This is more idiomatic and less error-prone.

      } else {
        iter = match_nodes.erase(iter);
      }

[cursor]

Cursor Bugbot has reviewed your changes using default effort and found 1 potential issue.

^{Reviewed by Cursor Bugbot for commit 8c9a394. Configure here.}

[cursor]

Unclear PR description

Low Severity

⚠️ This PR needs a clearer title and/or description.

This violates the Clear PR Descriptions and Titles rule. The description still includes template boilerplate and restates the title without explaining what the iterator invalidation problem is or how this change fixes it. A short sentence for each would help reviewers.

 

^{Triggered by project rule: Bugbot Rules}

^{Reviewed by Cursor Bugbot for commit 8c9a394. Configure here.}