SONARJAVA-6759: Avoid overlap between S1244 and S9147 for NaN comparisons

[romainbrenguier]

Summary

• S1244 (FloatEqualityCheck) no longer raises issues when a float/double is compared to Double.NaN or Float.NaN, since this case is already covered by S9147 (NanEqualityCheck)
• Added S1244 as a related rule in the S9147 Rspec HTML documentation
  See rspec PR: https://github.com/SonarSource/rspec/pull/7904
• Added test cases in FloatEquality.java to verify NaN comparisons are compliant for S1244

Test plan

• FloatEqualityCheckTest passes (both with and without semantic analysis)
• NanEqualityCheckTest passes (unchanged)
• CI integration tests pass

🤖 Generated with Claude Code

[hashicorp-vault-sonar-prod]

SONARJAVA-6759

[gitar-bot]

Code Review ✅ Approved 1 resolved / 1 findings

Extracts shared NaN detection logic to prevent rule overlap between S1244 and S9147, addressing the NaN detection logic duplication finding. No issues found.

✅ 1 resolved

✅ Quality: NaN detection logic duplicated across S1244 and S9147

📄 java-checks/src/main/java/org/sonar/java/checks/FloatEqualityCheck.java:100-114
isNanExpression/isFloatingPointNan in FloatEqualityCheck are near-identical copies of getNanTypeName/resolveNanOwnerType in NanEqualityCheck. Since the two must stay in sync for the overlap-avoidance to remain correct, any future change to NaN detection in one rule must be manually mirrored in the other, risking divergence. Consider extracting a shared helper (e.g. in ExpressionUtils or a common util) so both rules reference one source of truth.

Implementation Status ✅ 1 / 1 issues implemented

✅ SONARJAVA-6759 — 2 / 2 objectives

The PR successfully updates FloatEqualityCheck (S1244) to avoid raising on NaN comparisons and marks S9147 as related to S1244 in the Rspec.

✅ 2 complete

• ✅ Ensure S1244 does not raise when a float is compared to NaN
• ✅ Mark S9147 as related to S1244 in the Rspec

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[sonarqube-next]

Quality Gate passed

Issues
0 New issues
0 Fixed issues
0 Accepted issues

Measures
0 Security Hotspots
0 Dependency risks
100.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube