rust-best-practices

1# Rust best practices
2 
3Distilled from five Rust style and design guides, with a digest of each in `references/`.
4Where they disagree, this file says which to follow and why.
5 
6## 1. Mindset
7 
8- **Write Rust-shaped code.** Don't port C++, Java, C#, or Python constructs one-to-one.
9  Model errors with `Result`, resources with ownership and `Drop`, polymorphism with
10  traits and enums, and nullability with `Option`. Inheritance-flavored tricks (`Deref` to
11  a "base" struct, `Manager`/`Factory` types, `throw_if_null` helpers) are smells.
12- **Make invalid states unrepresentable.** Push invariants into types: enums instead of
13  bool flags and "must be X if Y" comments, newtypes for units and IDs, fallible
14  constructors that validate once. Then the compiler enforces what a comment only requests.
15- **Application code is not library code.** Library code (anything with external users)
16  follows the API-design rules below strictly. Application code should favor simplicity
17  and directness: concrete types, `String` or `&str` rather than `impl Into<String>`
18  parameters, `anyhow`-style errors, `Vec` return values, no speculative generality.
19- **Let the tools do the work.** rustfmt owns formatting, clippy owns idiom checks, the
20  compiler owns memory safety. Spend your attention on design.
21 
22## 2. Before you hand back code
23 
24Run these and fix everything they report:
25 
26```bash
27cargo fmt
28cargo clippy --all-targets --all-features -- -D warnings
29cargo test
30…