Hint Registry Lock Optimization

Summary

This update improves the performance and concurrency of the hint registry by making the following changes:

• Replaced write lock with read lock in GetRegisteredHint, allowing multiple goroutines to safely access the registry simultaneously.
• Switched cloneHintRegistry to use a read lock, ensuring the registry can be copied without blocking other concurrent readers.
• Maintained strict write locking in RegisterNamedHint to prevent duplicate key registration and preserve thread safety.

These changes reduce lock contention and improve overall registry responsiveness, especially in read-heavy workloads.

Testing

go test ./constraint/solver

Key Improvement Suggestions (Future Work)

Add Concurrency-Focused Tests

Introduce tests to simulate high-concurrency access to the registry and detect race conditions or locking regressions. These tests will help ensure thread safety during future updates or refactoring.

Standardize Read/Write Lock Usage

Review other shared-state access patterns across the codebase to ensure consistent and appropriate use of RLock vs Lock. Prefer RLock in read-heavy scenarios to improve concurrency.

Integrate Automated Linting Rules

Implement static analysis tools or CI checks to flag potential misuse of sync.Mutex and sync.RWMutex during development and code review. This will help maintain thread safety and code quality over time.