return type-erased Errors in AssetLoader::load

this fixes bevyengine#10350

Previous change made in bevyengine#10003
resulted in inability for users to have ?Sized errors, which caused
usability issues with crates like anyhow.

crates/bevy_asset/src/lib.rs

@@ -89,7 +89,7 @@ pub enum AssetMode {
     ///
     /// When developing an app, you should enable the `asset_processor` cargo feature, which will run the asset processor at startup. This should generally
     /// be used in combination with the `file_watcher` cargo feature, which enables hot-reloading of assets that have changed. When both features are enabled,
-    /// changes to "original/source assets" will be detected, the asset will be re-processed, and then the final processed asset will be hot-reloaded in the app.  
+    /// changes to "original/source assets" will be detected, the asset will be re-processed, and then the final processed asset will be hot-reloaded in the app.
     ///
     /// [`AssetMeta`]: crate::meta::AssetMeta
     /// [`AssetSource`]: crate::io::AssetSource
@@ -459,22 +459,20 @@ mod tests {
 
         type Settings = ();
 
-        type Error = CoolTextLoaderError;
-
         fn load<'a>(
             &'a self,
             reader: &'a mut Reader,
             _settings: &'a Self::Settings,
             load_context: &'a mut LoadContext,
-        ) -> BoxedFuture<'a, Result<Self::Asset, Self::Error>> {
+        ) -> BoxedFuture<'a, Result<Self::Asset, bevy_asset::Error>> {
             Box::pin(async move {
                 let mut bytes = Vec::new();
                 reader.read_to_end(&mut bytes).await?;
                 let mut ron: CoolTextRon = ron::de::from_bytes(&bytes)?;
                 let mut embedded = String::new();
                 for dep in ron.embedded_dependencies {
                     let loaded = load_context.load_direct(&dep).await.map_err(|_| {
-                        Self::Error::CannotLoadDependency {
+                        CoolTextLoaderError::CannotLoadDependency {
                             dependency: dep.into(),
                         }
                     })?;

crates/bevy_asset/src/loader.rs

@@ -20,22 +20,22 @@ use std::{
 };
 use thiserror::Error;
 
+pub type Error = Box<dyn std::error::Error + Send + Sync + 'static>;
+
 /// Loads an [`Asset`] from a given byte [`Reader`]. This can accept [`AssetLoader::Settings`], which configure how the [`Asset`]
 /// should be loaded.
 pub trait AssetLoader: Send + Sync + 'static {
     /// The top level [`Asset`] loaded by this [`AssetLoader`].
     type Asset: crate::Asset;
     /// The settings type used by this [`AssetLoader`].
     type Settings: Settings + Default + Serialize + for<'a> Deserialize<'a>;
-    /// The type of [error](`std::error::Error`) which could be encountered by this loader.
-    type Error: std::error::Error + Send + Sync + 'static;
     /// Asynchronously loads [`AssetLoader::Asset`] (and any other labeled assets) from the bytes provided by [`Reader`].
     fn load<'a>(
         &'a self,
         reader: &'a mut Reader,
         settings: &'a Self::Settings,
         load_context: &'a mut LoadContext,
-    ) -> BoxedFuture<'a, Result<Self::Asset, Self::Error>>;
+    ) -> BoxedFuture<'a, Result<Self::Asset, Error>>;
 
     /// Returns a list of extensions supported by this asset loader, without the preceding dot.
     fn extensions(&self) -> &[&str];
@@ -49,10 +49,7 @@ pub trait ErasedAssetLoader: Send + Sync + 'static {
         reader: &'a mut Reader,
         meta: Box<dyn AssetMetaDyn>,
         load_context: LoadContext<'a>,
-    ) -> BoxedFuture<
-        'a,
-        Result<ErasedLoadedAsset, Box<dyn std::error::Error + Send + Sync + 'static>>,
-    >;
+    ) -> BoxedFuture<'a, Result<ErasedLoadedAsset, Error>>;
 
     /// Returns a list of extensions supported by this asset loader, without the preceding dot.
     fn extensions(&self) -> &[&str];
@@ -80,10 +77,7 @@ where
         reader: &'a mut Reader,
         meta: Box<dyn AssetMetaDyn>,
         mut load_context: LoadContext<'a>,
-    ) -> BoxedFuture<
-        'a,
-        Result<ErasedLoadedAsset, Box<dyn std::error::Error + Send + Sync + 'static>>,
-    > {
+    ) -> BoxedFuture<'a, Result<ErasedLoadedAsset, Error>> {
         Box::pin(async move {
             let settings = meta
                 .loader_settings()
@@ -446,7 +440,7 @@ impl<'a> LoadContext<'a> {
     /// Retrieves a handle for the asset at the given path and adds that path as a dependency of the asset.
     /// If the current context is a normal [`AssetServer::load`], an actual asset load will be kicked off immediately, which ensures the load happens
     /// as soon as possible.
-    /// "Normal loads" kicked from within a normal Bevy App will generally configure the context to kick off loads immediately.  
+    /// "Normal loads" kicked from within a normal Bevy App will generally configure the context to kick off loads immediately.
     /// If the current context is configured to not load dependencies automatically (ex: [`AssetProcessor`](crate::processor::AssetProcessor)),
     /// a load will not be kicked off automatically. It is then the calling context's responsibility to begin a load if necessary.
     pub fn load<'b, A: Asset>(&mut self, path: impl Into<AssetPath<'b>>) -> Handle<A> {
@@ -462,7 +456,7 @@ impl<'a> LoadContext<'a> {
 
     /// Loads the [`Asset`] of type `A` at the given `path` with the given [`AssetLoader::Settings`] settings `S`. This is a "deferred"
     /// load. If the settings type `S` does not match the settings expected by `A`'s asset loader, an error will be printed to the log
-    /// and the asset load will fail.  
+    /// and the asset load will fail.
     pub fn load_with_settings<'b, A: Asset, S: Settings + Default>(
         &mut self,
         path: impl Into<AssetPath<'b>>,

crates/bevy_asset/src/meta.rs

@@ -193,13 +193,12 @@ impl VisitAssetDependencies for () {
 impl AssetLoader for () {
     type Asset = ();
     type Settings = ();
-    type Error = std::io::Error;
     fn load<'a>(
         &'a self,
         _reader: &'a mut crate::io::Reader,
         _settings: &'a Self::Settings,
         _load_context: &'a mut crate::LoadContext,
-    ) -> bevy_utils::BoxedFuture<'a, Result<Self::Asset, Self::Error>> {
+    ) -> bevy_utils::BoxedFuture<'a, Result<Self::Asset, bevy_asset::Error>> {
         unreachable!();
     }
 

crates/bevy_asset/src/processor/process.rs

@@ -107,7 +107,7 @@ pub enum ProcessError {
     #[error("The wrong meta type was passed into a processor. This is probably an internal implementation error.")]
     WrongMetaType,
     #[error("Encountered an error while saving the asset: {0}")]
-    AssetSaveError(#[from] Box<dyn std::error::Error + Send + Sync + 'static>),
+    AssetSaveError(#[from] crate::Error),
     #[error("Assets without extensions are not supported.")]
     ExtensionRequired,
 }
@@ -138,7 +138,7 @@ impl<Loader: AssetLoader, Saver: AssetSaver<Asset = Loader::Asset>> Process
                 .saver
                 .save(writer, saved_asset, &settings.saver_settings)
                 .await
-                .map_err(|error| ProcessError::AssetSaveError(Box::new(error)))?;
+                .map_err(|error| ProcessError::AssetSaveError(error))?;
             Ok(output_settings)
         })
     }

crates/bevy_asset/src/saver.rs

@@ -13,29 +13,27 @@ pub trait AssetSaver: Send + Sync + 'static {
     type Settings: Settings + Default + Serialize + for<'a> Deserialize<'a>;
     /// The type of [`AssetLoader`] used to load this [`Asset`]
     type OutputLoader: AssetLoader;
-    /// The type of [error](`std::error::Error`) which could be encountered by this saver.
-    type Error: std::error::Error + Send + Sync + 'static;
 
     /// Saves the given runtime [`Asset`] by writing it to a byte format using `writer`. The passed in `settings` can influence how the
-    /// `asset` is saved.  
+    /// `asset` is saved.
     fn save<'a>(
         &'a self,
         writer: &'a mut Writer,
         asset: SavedAsset<'a, Self::Asset>,
         settings: &'a Self::Settings,
-    ) -> BoxedFuture<'a, Result<<Self::OutputLoader as AssetLoader>::Settings, Self::Error>>;
+    ) -> BoxedFuture<'a, Result<<Self::OutputLoader as AssetLoader>::Settings, crate::Error>>;
 }
 
 /// A type-erased dynamic variant of [`AssetSaver`] that allows callers to save assets without knowing the actual type of the [`AssetSaver`].
 pub trait ErasedAssetSaver: Send + Sync + 'static {
     /// Saves the given runtime [`ErasedLoadedAsset`] by writing it to a byte format using `writer`. The passed in `settings` can influence how the
-    /// `asset` is saved.  
+    /// `asset` is saved.
     fn save<'a>(
         &'a self,
         writer: &'a mut Writer,
         asset: &'a ErasedLoadedAsset,
         settings: &'a dyn Settings,
-    ) -> BoxedFuture<'a, Result<(), Box<dyn std::error::Error + Send + Sync + 'static>>>;
+    ) -> BoxedFuture<'a, Result<(), crate::Error>>;
 
     /// The type name of the [`AssetSaver`].
     fn type_name(&self) -> &'static str;
@@ -47,7 +45,7 @@ impl<S: AssetSaver> ErasedAssetSaver for S {
         writer: &'a mut Writer,
         asset: &'a ErasedLoadedAsset,
         settings: &'a dyn Settings,
-    ) -> BoxedFuture<'a, Result<(), Box<dyn std::error::Error + Send + Sync + 'static>>> {
+    ) -> BoxedFuture<'a, Result<(), crate::Error>> {
         Box::pin(async move {
             let settings = settings
                 .downcast_ref::<S::Settings>()

crates/bevy_asset/src/server/mod.rs

@@ -33,7 +33,7 @@ use thiserror::Error;
 /// The general process to load an asset is:
 /// 1. Initialize a new [`Asset`] type with the [`AssetServer`] via [`AssetApp::init_asset`], which will internally call [`AssetServer::register_asset`]
 /// and set up related ECS [`Assets`] storage and systems.
-/// 2. Register one or more [`AssetLoader`]s for that asset with [`AssetApp::init_asset_loader`]  
+/// 2. Register one or more [`AssetLoader`]s for that asset with [`AssetApp::init_asset_loader`]
 /// 3. Add the asset to your asset folder (defaults to `assets`).
 /// 4. Call [`AssetServer::load`] with a path to your asset.
 ///
@@ -957,7 +957,7 @@ enum MaybeAssetLoader {
     },
 }
 
-/// Internal events for asset load results  
+/// Internal events for asset load results
 #[allow(clippy::large_enum_variant)]
 pub(crate) enum InternalAssetEvent {
     Loaded {
@@ -1046,7 +1046,7 @@ pub enum AssetLoadError {
     AssetLoaderError {
         path: AssetPath<'static>,
         loader_name: &'static str,
-        error: Box<dyn std::error::Error + Send + Sync + 'static>,
+        error: crate::Error,
     },
     #[error("The file at '{base_path}' does not contain the labeled asset '{label}'.")]
     MissingLabel {

crates/bevy_audio/src/audio_source.rs

@@ -41,14 +41,13 @@ pub struct AudioLoader;
 impl AssetLoader for AudioLoader {
     type Asset = AudioSource;
     type Settings = ();
-    type Error = std::io::Error;
 
     fn load<'a>(
         &'a self,
         reader: &'a mut Reader,
         _settings: &'a Self::Settings,
         _load_context: &'a mut LoadContext,
-    ) -> BoxedFuture<'a, Result<AudioSource, Self::Error>> {
+    ) -> BoxedFuture<'a, Result<AudioSource, bevy_asset::Error>> {
         Box::pin(async move {
             let mut bytes = Vec::new();
             reader.read_to_end(&mut bytes).await?;
@@ -113,7 +112,7 @@ pub trait AddAudioSource {
     /// so that it can be converted to a [`rodio::Source`] type,
     /// and [`Asset`], so that it can be registered as an asset.
     /// To use this method on [`App`][bevy_app::App],
-    /// the [audio][super::AudioPlugin] and [asset][bevy_asset::AssetPlugin] plugins must be added first.    
+    /// the [audio][super::AudioPlugin] and [asset][bevy_asset::AssetPlugin] plugins must be added first.
     fn add_audio_source<T>(&mut self) -> &mut Self
     where
         T: Decodable + Asset,

crates/bevy_gltf/src/loader.rs

@@ -108,17 +108,16 @@ pub struct GltfLoader {
 impl AssetLoader for GltfLoader {
     type Asset = Gltf;
     type Settings = ();
-    type Error = GltfError;
     fn load<'a>(
         &'a self,
         reader: &'a mut Reader,
         _settings: &'a (),
         load_context: &'a mut LoadContext,
-    ) -> bevy_utils::BoxedFuture<'a, Result<Gltf, Self::Error>> {
+    ) -> bevy_utils::BoxedFuture<'a, Result<Gltf, bevy_asset::Error>> {
         Box::pin(async move {
             let mut bytes = Vec::new();
             reader.read_to_end(&mut bytes).await?;
-            load_gltf(self, &bytes, load_context).await
+            Ok(load_gltf(self, &bytes, load_context).await?)
         })
     }
 

crates/bevy_render/src/render_resource/shader.rs

@@ -250,13 +250,12 @@ pub enum ShaderLoaderError {
 impl AssetLoader for ShaderLoader {
     type Asset = Shader;
     type Settings = ();
-    type Error = ShaderLoaderError;
     fn load<'a>(
         &'a self,
         reader: &'a mut Reader,
         _settings: &'a Self::Settings,
         load_context: &'a mut LoadContext,
-    ) -> BoxedFuture<'a, Result<Shader, Self::Error>> {
+    ) -> BoxedFuture<'a, Result<Shader, bevy_asset::Error>> {
         Box::pin(async move {
             let ext = load_context.path().extension().unwrap().to_str().unwrap();
 

crates/bevy_render/src/texture/hdr_texture_loader.rs

@@ -19,13 +19,12 @@ pub enum HdrTextureLoaderError {
 impl AssetLoader for HdrTextureLoader {
     type Asset = Image;
     type Settings = ();
-    type Error = HdrTextureLoaderError;
     fn load<'a>(
         &'a self,
         reader: &'a mut Reader,
         _settings: &'a (),
         _load_context: &'a mut LoadContext,
-    ) -> bevy_utils::BoxedFuture<'a, Result<Image, Self::Error>> {
+    ) -> bevy_utils::BoxedFuture<'a, Result<Image, bevy_asset::Error>> {
         Box::pin(async move {
             let format = TextureFormat::Rgba32Float;
             debug_assert_eq!(

crates/bevy_render/src/texture/image_loader.rs

@@ -81,13 +81,12 @@ pub enum ImageLoaderError {
 impl AssetLoader for ImageLoader {
     type Asset = Image;
     type Settings = ImageLoaderSettings;
-    type Error = ImageLoaderError;
     fn load<'a>(
         &'a self,
         reader: &'a mut Reader,
         settings: &'a ImageLoaderSettings,
         load_context: &'a mut LoadContext,
-    ) -> bevy_utils::BoxedFuture<'a, Result<Image, Self::Error>> {
+    ) -> bevy_utils::BoxedFuture<'a, Result<Image, bevy_asset::Error>> {
         Box::pin(async move {
             // use the file extension for the image type
             let ext = load_context.path().extension().unwrap().to_str().unwrap();

crates/bevy_scene/src/scene_loader.rs

@@ -41,14 +41,13 @@ pub enum SceneLoaderError {
 impl AssetLoader for SceneLoader {
     type Asset = DynamicScene;
     type Settings = ();
-    type Error = SceneLoaderError;
 
     fn load<'a>(
         &'a self,
         reader: &'a mut Reader,
         _settings: &'a (),
         _load_context: &'a mut LoadContext,
-    ) -> BoxedFuture<'a, Result<Self::Asset, Self::Error>> {
+    ) -> BoxedFuture<'a, Result<Self::Asset, bevy_asset::Error>> {
         Box::pin(async move {
             let mut bytes = Vec::new();
             reader.read_to_end(&mut bytes).await?;

crates/bevy_text/src/font_loader.rs

@@ -20,13 +20,12 @@ pub enum FontLoaderError {
 impl AssetLoader for FontLoader {
     type Asset = Font;
     type Settings = ();
-    type Error = FontLoaderError;
     fn load<'a>(
         &'a self,
         reader: &'a mut Reader,
         _settings: &'a (),
         _load_context: &'a mut LoadContext,
-    ) -> bevy_utils::BoxedFuture<'a, Result<Font, Self::Error>> {
+    ) -> bevy_utils::BoxedFuture<'a, Result<Font, bevy_asset::Error>> {
         Box::pin(async move {
             let mut bytes = Vec::new();
             reader.read_to_end(&mut bytes).await?;

examples/asset/custom_asset.rs

@@ -34,13 +34,12 @@ pub enum CustomAssetLoaderError {
 impl AssetLoader for CustomAssetLoader {
     type Asset = CustomAsset;
     type Settings = ();
-    type Error = CustomAssetLoaderError;
     fn load<'a>(
         &'a self,
         reader: &'a mut Reader,
         _settings: &'a (),
         _load_context: &'a mut LoadContext,
-    ) -> BoxedFuture<'a, Result<Self::Asset, Self::Error>> {
+    ) -> BoxedFuture<'a, Result<Self::Asset, bevy::asset::Error>> {
         Box::pin(async move {
             let mut bytes = Vec::new();
             reader.read_to_end(&mut bytes).await?;