# Objective

- Fixes bevyengine#8140

## Solution

- Added Explicit Error Typing for `AssetLoader` and `AssetSaver`, which
were the last instances of `anyhow` in use across Bevy.

---

## Changelog

- Added an associated type `Error` to `AssetLoader` and `AssetSaver` for
use with the `load` and `save` methods respectively.
- Changed `ErasedAssetLoader` and `ErasedAssetSaver` `load` and `save`
methods to use `Box<dyn Error + Send + Sync + 'static>` to allow for
arbitrary `Error` types from the non-erased trait variants. Note the
strict requirements match the pre-existing requirements around
`anyhow::Error`.

## Migration Guide

- `anyhow` is no longer exported by `bevy_asset`; Add it to your own
project (if required).
- `AssetLoader` and `AssetSaver` have an associated type `Error`; Define
an appropriate error type (e.g., using `thiserror`), or use a pre-made
error type (e.g., `anyhow::Error`). Note that using `anyhow::Error` is a
drop-in replacement.
- `AssetLoaderError` has been removed; Define a new error type, or use
an alternative (e.g., `anyhow::Error`)
- All the first-party `AssetLoader`'s and `AssetSaver`'s now return
relevant (and narrow) error types instead of a single ambiguous type;
Match over the specific error type, or encapsulate (`Box<dyn>`,
`thiserror`, `anyhow`, etc.)

## Notes

A simpler PR to resolve this issue would simply define a Bevy `Error`
type defined as `Box<dyn std::error::Error + Send + Sync + 'static>`,
but I think this type of error handling should be discouraged when
possible. Since only 2 traits required the use of `anyhow`, it isn't a
substantive body of work to solidify these error types, and remove
`anyhow` entirely. End users are still encouraged to use `anyhow` if
that is their preferred error handling style. Arguably, adding the
`Error` associated type gives more freedom to end-users to decide
whether they want more or less explicit error handling (`anyhow` vs
`thiserror`).

As an aside, I didn't perform any testing on Android or WASM. CI passed
locally, but there may be mistakes for those platforms I missed.

# Objective

- Fixes bevyengine#8140

## Solution

- Added Explicit Error Typing for `AssetLoader` and `AssetSaver`, which
were the last instances of `anyhow` in use across Bevy.

---

## Changelog

- Added an associated type `Error` to `AssetLoader` and `AssetSaver` for
use with the `load` and `save` methods respectively.
- Changed `ErasedAssetLoader` and `ErasedAssetSaver` `load` and `save`
methods to use `Box<dyn Error + Send + Sync + 'static>` to allow for
arbitrary `Error` types from the non-erased trait variants. Note the
strict requirements match the pre-existing requirements around
`anyhow::Error`.

## Migration Guide

- `anyhow` is no longer exported by `bevy_asset`; Add it to your own
project (if required).
- `AssetLoader` and `AssetSaver` have an associated type `Error`; Define
an appropriate error type (e.g., using `thiserror`), or use a pre-made
error type (e.g., `anyhow::Error`). Note that using `anyhow::Error` is a
drop-in replacement.
- `AssetLoaderError` has been removed; Define a new error type, or use
an alternative (e.g., `anyhow::Error`)
- All the first-party `AssetLoader`'s and `AssetSaver`'s now return
relevant (and narrow) error types instead of a single ambiguous type;
Match over the specific error type, or encapsulate (`Box<dyn>`,
`thiserror`, `anyhow`, etc.)

## Notes

A simpler PR to resolve this issue would simply define a Bevy `Error`
type defined as `Box<dyn std::error::Error + Send + Sync + 'static>`,
but I think this type of error handling should be discouraged when
possible. Since only 2 traits required the use of `anyhow`, it isn't a
substantive body of work to solidify these error types, and remove
`anyhow` entirely. End users are still encouraged to use `anyhow` if
that is their preferred error handling style. Arguably, adding the
`Error` associated type gives more freedom to end-users to decide
whether they want more or less explicit error handling (`anyhow` vs
`thiserror`).

As an aside, I didn't perform any testing on Android or WASM. CI passed
locally, but there may be mistakes for those platforms I missed.

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.

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.

# Objective

- Fixes bevyengine#8140

## Solution

- Added Explicit Error Typing for `AssetLoader` and `AssetSaver`, which
were the last instances of `anyhow` in use across Bevy.

---

## Changelog

- Added an associated type `Error` to `AssetLoader` and `AssetSaver` for
use with the `load` and `save` methods respectively.
- Changed `ErasedAssetLoader` and `ErasedAssetSaver` `load` and `save`
methods to use `Box<dyn Error + Send + Sync + 'static>` to allow for
arbitrary `Error` types from the non-erased trait variants. Note the
strict requirements match the pre-existing requirements around
`anyhow::Error`.

## Migration Guide

- `anyhow` is no longer exported by `bevy_asset`; Add it to your own
project (if required).
- `AssetLoader` and `AssetSaver` have an associated type `Error`; Define
an appropriate error type (e.g., using `thiserror`), or use a pre-made
error type (e.g., `anyhow::Error`). Note that using `anyhow::Error` is a
drop-in replacement.
- `AssetLoaderError` has been removed; Define a new error type, or use
an alternative (e.g., `anyhow::Error`)
- All the first-party `AssetLoader`'s and `AssetSaver`'s now return
relevant (and narrow) error types instead of a single ambiguous type;
Match over the specific error type, or encapsulate (`Box<dyn>`,
`thiserror`, `anyhow`, etc.)

## Notes

A simpler PR to resolve this issue would simply define a Bevy `Error`
type defined as `Box<dyn std::error::Error + Send + Sync + 'static>`,
but I think this type of error handling should be discouraged when
possible. Since only 2 traits required the use of `anyhow`, it isn't a
substantive body of work to solidify these error types, and remove
`anyhow` entirely. End users are still encouraged to use `anyhow` if
that is their preferred error handling style. Arguably, adding the
`Error` associated type gives more freedom to end-users to decide
whether they want more or less explicit error handling (`anyhow` vs
`thiserror`).

As an aside, I didn't perform any testing on Android or WASM. CI passed
locally, but there may be mistakes for those platforms I missed.