Rust Skill

When to use

Use for any task touching Rust code, Cargo, clippy, unsafe blocks, async runtime, or benchmarks.

Workflow

1. Read module boundaries and trait contracts first.
2. Make the smallest safe change that solves the issue.
3. Prefer clear ownership/lifetime design over complex workarounds.
4. Add or update tests for behavior changes.
5. Validate with fmt, clippy, and tests.

Repo commands

• Format: cargo fmt --all
• Lints: cargo clippy --all-targets --all-features -- -D warnings
• Tests: cargo test --all
• Check quickly: cargo check --all-targets --all-features

Design rules

• Favor enums and pattern matching for state machines.
• Use Result with domain-specific errors; avoid unwrap() in production paths.
• Keep public API minimal and documented.
• Prefer iterators and zero-copy paths when it keeps readability acceptable.

Async and Concurrency

• Never block async executors with sync I/O or long CPU tasks.
• Use cancellation-aware patterns and explicit timeouts.
• Protect shared mutable state with clear ownership or narrow lock scopes.

Unsafe code

• Keep unsafe blocks tiny and documented with invariants.
• Add tests specifically covering invariant boundaries.
• Prefer safe wrappers exposing safe API to callers.

Testing and quality

• Unit tests for logic, integration tests for module interaction.
• Add regression tests for bug fixes.
• For perf-sensitive paths, include criterion or reproducible benchmark notes.

PR checklist

• fmt, clippy, test are clean.
• No hidden panic paths in non-test code.
• Error messages provide actionable context.
• Concurrency behavior has explicit assumptions.