bevy/.github/contributing/engine_style_guide.md

Style guide: Engine

Contributing

For more advice on contributing to the engine, see the relevant section of CONTRIBUTING.md.

General guidelines

1. Prefer granular imports over glob imports like bevy_ecs::prelude::*.
2. Use a consistent comment style:
   1. /// doc comments belong above #[derive(Trait)] invocations.
   2. // comments should generally go above the line in question, rather than in-line.
   3. Avoid /* */ block comments, even when writing long comments.
   4. Use `variable_name` code blocks in comments to signify that you're referring to specific types and variables.
   5. Start comments with capital letters. End them with a period if they are sentence-like.
3. Use comments to organize long and complex stretches of code that can't sensibly be refactored into separate functions.

Rust API guidelines

As a reference for our API development we are using the Rust API guidelines. Generally, these should be followed, except for the following areas of disagreement:

Areas of disagreements

Some areas mentioned in the Rust API guidelines we do not agree with. These areas will be expanded whenever we find something else we do not agree with, so be sure to check these from time to time.

All items have a rustdoc example

• This guideline is too strong and not applicable for everything inside of the Bevy game engine. For functionality that requires more context or needs a more interactive demonstration (such as rendering or input features), make use of the examples folder instead.

Examples use ?, not try!, not unwrap

• This guideline is usually reasonable, but not always required.

Only smart pointers implement Deref and DerefMut

• Generally a good rule of thumb, but we're probably going to deliberately violate this for single-element wrapper types like Life(u32). The behavior is still predictable and it significantly improves ergonomics / new user comprehension.