code-quality

Source excerpt starting at line 1.

1---2name: code-quality3description: General Correctness rules, Rust patterns, comments, avoiding over-engineering. When writing code always take these into account4---5# Code Quality Guide6 7## Core Principle8 9Production database. Correctness paramount. Crash > corrupt.10 11## Correctness Rules12 131. **No workarounds or quick hacks.** Handle all errors, check invariants142. **Assert often.** Never silently fail or swallow edge cases153. **Crash on invalid state** if it risks data integrity. Don't continue in undefined state164. **Consider edge cases.** On long enough timeline, all possible bugs will happen17 18## Rust Patterns19 20- Make illegal states unrepresentable21- Exhaustive pattern matching22- Prefer enums over strings/sentinels23- Minimize heap allocations24- Write CPU-friendly code (microsecond = long time)25 26## If-Statements27 28Wrong:29```rust30if condition {31    // happy path32} else {33    // "shouldn't happen" - silently ignored34}35```36 37Right:38```rust39// If only one branch should ever be hit:40assert!(condition, "invariant violated: ...");41// OR42return Err(LimboError::InternalError("unexpected state".into()));43// OR44unreachable!("impossible state: ...");45```46 47Use if-statements only when both branches are expected paths.48 49## Comments50 51**Do:**52- Document WHY, not what53- Document functions, structs, enums, variants54- Focus on why something is necessary55 56**Don't:**57- Comments that repeat code58- References to AI conversations ("This test should trigger the bug")59- Temporal markers ("added", "existing code", "Phase 1")60 61## Avoid Over-Engineering62 63- Only changes directly requested or clearly necessary64- Don't add features beyond what's asked65- Don't add docstrings/comments to unchanged code66- Don't add error handling for impossible scenarios67- Don't create abstractions for one-time operations68- Three similar lines > premature abstraction69 70## Index Mutations71 72When code involves index inserts, deletes, or conflict resolution, double-check the ordering against SQLite. Wrong ordering causes index inconsistencies. and easy to miss.73 74## Ensure understanding of IO model75 76- [Async IO model](../async-io-model/SKILL.md)77 78## Cleanup79 80- Delete unused code completely81- No backwards-compat hacks (renamed `_vars`, re-exports, `// removed` comments)82