fix(inlay): prevent NPE in parameter hint scoring

[albertocavalcante]

Summary

Summary by CodeRabbit

• Bug Fixes
  • Improved edge case handling in hint generation to gracefully process edge cases and enhance stability.

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[gemini-code-assist]

Summary of Changes

Hello @albertocavalcante, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request addresses a potential NullPointerException within the inlay hints provider. By refining the logic for handling argument types during parameter hint scoring, it ensures that null or unknown types are gracefully skipped, thereby enhancing the stability and robustness of the inlay hint functionality.

Highlights

• Null Pointer Exception Prevention: Modified the scoreParameterHint function to explicitly handle null or unknown argument types, preventing a potential NullPointerException when calculating parameter hint scores.
• Improved Type Handling: Introduced a nonNullArgType variable to safely process argument types, ensuring that matchScore is only called with valid, known types, replacing the unsafe argType!! assertion.

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[coderabbitai]

📝 Walkthrough

Walkthrough

A single file modification improves null-safety handling in the InlayHints scoring logic by replacing unsafe argument type assertions with explicit null and unknown type checks using conditional expressions.

Changes

Cohort / File(s)	Summary
Null-safety refactoring gls/src/main/kotlin/com/github/albertocavalcante/gvy/gls/providers/inlayhints/InlayHintsProvider.kt	Modified scoreCandidate method to handle null and unknown argument types gracefully using takeUnless and safe optional chaining instead of unsafe assertions, maintaining identical scoring logic.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~8 minutes

Poem

A bunny hops through types with care,
No more unsafe casts laid bare,
With takeUnless and gentle flow,
Null-safe whiskers steal the show! 🐰

🚥 Pre-merge checks | ✅ 2 | ❌ 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 (2 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title accurately describes the main change: preventing null pointer exceptions in parameter hint scoring by safely handling null/unknown argument types.

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✨ Finishing touches

• 📝 Generate docstrings

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Post copyable unit tests in a comment
• Commit unit tests in branch fix/null-safety-inlay-hints

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[gemini-code-assist]

Code Review

This pull request addresses a potential null pointer exception in the parameter hint scoring logic by refactoring argument type validation to be more robust and idiomatic using takeUnless and the elvis operator, thereby removing a non-null assertion (!!). While the NPE is resolved, a security audit identified an inconsistency in type name validation before being passed to the class loader. Specifically, the functions resolveClass and findGdkMethodCandidates lack validation guards, which could allow malformed strings from the AST to reach sensitive class-loading sinks. It is recommended to apply consistent validation using TypeStringUtils.isValidClasspathTypeName to improve the robustness and security of the provider.

[Copilot]

Pull request overview

Adjusts inlay-hint parameter candidate scoring to avoid potential null dereferences when argument type inference fails.

Changes:

• Skip scoring for arguments whose inferred type is null or considered “unknown”.
• Remove unsafe !! usage when passing argument types into matchScore.

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[Copilot]

Add a regression test covering the case where at least one entry in argumentTypes is null (e.g., SemanticTypeResolver.resolveType fails for one argument) while other arguments have known types, to ensure candidate scoring does not throw and still resolves the correct overload/parameter names. There are already comprehensive InlayHintsProviderTest/parameter hint tests, so this scenario should be easy to add and will prevent the NPE from reappearing.

[sonarqubecloud]

Quality Gate failed

Failed conditions
62.5% Coverage on New Code (required ≥ 80%)

See analysis details on SonarQube Cloud