SONARKT-681 S1862 should not raise when guard conditions are used in "when" statements

[petertrr]

Summary

Fixed S1862 rule to not raise when guard conditions are used in "when" statements in Kotlin.

Changes

• Updated S1862 inspection rule logic to properly handle guard conditions in when statements
• Added test cases to verify the fix works correctly

Testing

• Ran local tests to verify the fix
• Tested with sample code containing guard conditions in when statements

Ticket

SONARKT-681

[hashicorp-vault-sonar-prod]

SONARKT-681

[sonar-review-alpha]

Summary

The PR refines the S1862 rule (identical conditions) to properly handle guard conditions in Kotlin's when expressions. Previously, the rule would incorrectly flag identical patterns with different guards as duplicates. The fix introduces a new ConditionWithGuard data structure and a groupEquivalent() grouping function that treats two when entries as duplicates only when both their condition patterns AND their guard expressions are syntactically equivalent. This prevents false positives when the same pattern is guarded by different conditions.

What reviewers should know

Start with the test cases in IdenticalConditionsCheckSample.kt — the new test block starting at line 32 shows the fix in action with concrete examples. Notice how true if a == "foo" followed by true if a == "bar" are now compliant (no warning), but identical pattern+guard pairs still trigger the noncompliant warning.

Core logic is in checkWhenConditions() (replacing the old collectConditions()). The key change: instead of comparing raw conditions, the method now wraps conditions with their optional guard expressions in a ConditionWithGuard object, then groups using a custom predicate that checks both the condition and guard for syntactic equivalence. Review the predicate logic around line 73-77 — this is where the fix happens.

groupEquivalent() is a new helper that groups elements by a custom equivalence predicate. It's a straightforward implementation but worth understanding since it replaces the previous use of SyntacticEquivalence.findDuplicatedGroups() with custom logic.

Minor cleanup: SyntacticEquivalence.kt changes isNullOrEmpty() to isEmpty() (lists from .filterIsInstance() are never null).

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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
93.1% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube

[sonar-review-alpha]

LGTM! ✅

Solid fix. The guard-aware deduplication logic is correct, line numbers in // Noncompliant annotations are accurate, and the existing if-chain path is untouched.

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[matthew-reid-sonarsource]

LGTM!