fix: prevent LogoCarousel DOM cloning leak

[preeeetham]

Summary

• Fixes memory leak in LogoCarousel by removing DOM cloning in useEffect and rendering the duplicated sponsor list declaratively.
• Ensures stable unique keys even when sponsors contains repeated items.

Fixes #3754.

Test plan

• make check-test-frontend (format + lint passed; graphql-codegen requires backend running locally)
• pnpm exec jest __tests__/unit/components/LogoCarousel.test.tsx --coverage=false (pass)

Made with Cursor

[coderabbitai]

Summary by CodeRabbit

• Refactor
  • Optimized logo carousel component rendering and animation system. Animation duration now dynamically adjusts based on sponsor count, sponsor items render more reliably as data changes, and image handling is more robust when URLs are missing.

Walkthrough

Replaces imperative DOM cloning in the LogoCarousel with declarative JSX rendering: adds a renderSponsorCard helper, computes a stable animation duration, and renders sponsors twice (original + loop) to simulate continuous scrolling without DOM mutation or cleanup logic. No public API changes.

Changes

Cohort / File(s)	Summary
LogoCarousel refactor frontend/src/components/LogoCarousel.tsx	Removed useRef/useEffect DOM cloning and cleanup concerns; added renderSponsorCard helper, stable animation duration calculation (max(sponsors.length, 1) * 2), and duplicated render pass (original + loop keys) to achieve infinite scroll declaratively. Improved key generation and safe image/link handling.

Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~20 minutes

Possibly related PRs

• test: add comprehensive LogoCarousel unit tests #2275 — Changes the LogoCarousel/MovingLogos rendering and DOM-duplication/animation logic; strongly related to this refactor.

Suggested reviewers

• kasya

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly and concisely describes the main fix: preventing a DOM cloning memory leak in LogoCarousel.
Description check	✅ Passed	The description is directly related to the changeset, explaining the memory leak fix and the declarative rendering approach used.
Linked Issues check	✅ Passed	The PR successfully addresses all coding objectives from issue #3754: removes DOM cloning, implements declarative rendering in JSX, ensures stable unique keys, and preserves infinite-scroll behavior.
Out of Scope Changes check	✅ Passed	All changes are scoped to fixing the LogoCarousel memory leak issue and are directly related to the linked issue #3754 requirements.

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✨ Finishing touches

• 📝 Generate docstrings

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Post copyable unit tests in a comment

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[cubic-dev-ai]

No issues found across 1 file

Confidence score: 5/5

• Automated review surfaced no issues in the provided summaries.
• No files require special attention.

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[codecov]

Codecov Report

❌ Patch coverage is 80.00000% with 2 lines in your changes missing coverage. Please review.
✅ Project coverage is 90.24%. Comparing base (fe8eff8) to head (e66fdbe).
⚠️ Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
frontend/src/components/LogoCarousel.tsx	80.00%	0 Missing and 2 partials ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3801      +/-   ##
==========================================
- Coverage   90.25%   90.24%   -0.01%     
==========================================
  Files         463      463              
  Lines       14412    14410       -2     
  Branches     1934     1936       +2     
==========================================
- Hits        13008    13005       -3     
  Misses        987      987              
- Partials      417      418       +1     

Flag	Coverage Δ
backend	90.97% <ø> (ø)
frontend	88.22% <80.00%> (-0.04%)	⬇️

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

Files with missing lines	Coverage Δ
frontend/src/components/LogoCarousel.tsx	85.71% <80.00%> (-8.04%)	⬇️

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