SONARJAVA-6304: Implement S8218: Instant APIs should only use supported temporal units

[nathsou]

Summary

• Implement S8218 as a semantic SonarJava check for unsupported ChronoUnit constants used with Instant.
• Cover all supported and unsupported units, static imports, custom-unit boundaries, and missing semantics.
• Generate rule metadata and add S8218 to Sonar way.

Links

• Jira: https://sonarsource.atlassian.net/browse/SONARJAVA-6304
• RSPEC PR: https://github.com/SonarSource/rspec/pull/5780

AI disclosure

• LLM model used for implementation: gpt-5.6-sol

[hashicorp-vault-sonar-prod]

SONARJAVA-6304

[gitar-bot]

Code Review ✅ Approved 1 resolved / 1 findings

Implements new rule S8218 to check for unsupported ChronoUnit constants used with Instant APIs, addressing the unreachable guard finding in onMethodInvocationFound. No issues found.

✅ 1 resolved

✅ Quality: Unreachable guard in onMethodInvocationFound

📄 java-checks/src/main/java/org/sonar/java/checks/UnsupportedChronoUnitWithInstantCheck.java:74-78 📄 java-checks/src/test/java/org/sonar/java/checks/UnsupportedChronoUnitWithInstantCheckTest.java:36-43
onMethodInvocationFound is only invoked after MethodMatchers resolved the invocation against java.time.Instant, which requires semantics; with withoutSemantic() the method symbol is unknown and the callback never fires, so context.getSemanticModel() == null can never be true here. Likewise both matchers declare exactly two parameters, so mit.arguments().size() < 2 is never true. The two conditions are unreachable branches (and test_without_semantic does not actually exercise them); dropping them simplifies the check and avoids uncovered branches.

Implementation Status ✅ 3 of 3 objectives covered

✅ SONARJAVA-6304 - 3 of 3 objectives covered

This PR covers the implementation of rule S8218 by excluding custom TemporalUnit implementations and variable value propagation, while reporting unsupported ChronoUnit direct constants and static imports for Instant APIs.

✅ 3 covered here

• ✅ Exclude custom TemporalUnit implementations from reporting
• ✅ Exclude value propagation through variables in the initial implementation
• ✅ Report direct enum constants, including statically imported constants, only when semantic resolution confirms the symbol belongs to java.time.temporal.ChronoUnit

Options

Auto-apply is off → Gitar will not commit updates to this branch.
Display: compact → Showing less information.

Comment with these commands to change the behavior for this request:

Auto-apply	Compact
gitar auto-apply:on	gitar display:verbose

_{Was this helpful? React with 👍 / 👎 | Gitar}

[sonarqube-next]

Quality Gate passed

Issues
0 New issues
0 Fixed issues
0 Accepted issues

Measures
0 Security Hotspots
0 Dependency risks
92.6% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube