rust-development

CIEL ADAPTATION: Rust Development (Safety & Performance)

This skill formalizes the development of high-integrity Rust applications. it prioritizes ownership-aware design and making illegal states unrepresentable.

Idiomatic Standards

1. Ownership & Borrowing: Pass &T (borrow) by default. Clone ONLY when ownership is required and cannot be moved.
2. Error Handling:
   • Apps: Use anyhow for flexible error propagation with context.
   • Libraries: Use thiserror for structured, typed error variants.
   • Hard Gate: Prohibit .unwrap() or .expect() in production/library code. Use ? or unwrap_or.
3. Type-Driven Design: Use enum and exhaustive matching to eliminate illegal states. Use the "Newtype" pattern for primitive safety.

Architecture & Traits

• Trait Bounds: Use impl Trait for inputs. Use Box<dyn Trait> only when dynamic dispatch is required.
• Async (Tokio): Enforce tokio::spawn for concurrent tasks. Never block an async executor with std::thread::sleep.
• Visibility: Expose minimally. Prefer pub(crate) over pub.

TDD & Verification

• Doc Tests: Include executable examples in doc comments for all public APIs.
• Property-Based Testing: Use proptest for input validation and complex state transitions.
• LLVM Cov: Target 80%+ coverage using cargo llvm-cov.

Anti-Patterns

• Wildcard Matching: Using _ => {} in business-critical enums (hides new variants).
• String over &str: Using String for read-only function parameters.
• Unsafe Without Reason: Using unsafe without a // SAFETY: comment explaining the invariant.