bevy/examples/tools
Daniel McNab 1bbd5c25c0 Enforce type safe usage of Handle::get (#4794)
# Objective

- Sometimes, people might load an asset as one type, then use it with an `Asset`s for a different type.
- See e.g. #4784. 
- This is especially likely with the Gltf types, since users may not have a clear conceptual model of what types the assets will be.
- We had an instance of this ourselves, in the `scene_viewer` example

## Solution

- Make `Assets::get` require a type safe handle.

---

## Changelog

### Changed

- `Assets::<T>::get` and `Assets::<T>::get_mut` now require that the passed handles are `Handle<T>`, improving the type safety of handles.

### Added
- `HandleUntyped::typed_weak`, a helper function for creating a weak typed version of an exisitng `HandleUntyped`.

## Migration Guide

`Assets::<T>::get` and `Assets::<T>::get_mut` now require that the passed handles are `Handle<T>`, improving the type safety of handles. If you were previously passing in:
   - a `HandleId`, use `&Handle::weak(id)` instead, to create a weak handle. You may have been able to store a type safe `Handle` instead.
   - a `HandleUntyped`, use `&handle_untyped.typed_weak()` to create a weak handle of the specified type. This is most likely to be the useful when using [load_folder](https://docs.rs/bevy_asset/latest/bevy_asset/struct.AssetServer.html#method.load_folder)
   - a `Handle<U>` of  of a different type, consider whether this is the correct handle type to store. If it is (i.e. the same handle id is used for multiple different Asset types) use `Handle::weak(handle.id)` to cast to a different type.
2022-05-30 16:59:44 +00:00
..
scene_viewer.rs Enforce type safe usage of Handle::get (#4794) 2022-05-30 16:59:44 +00:00