723b52abd3
# Objective
- `LoadContext::labeled_asset_scope` cannot return errors back to the
asset loader. This means users that need errors need to fall back to
using the raw `begin_labeled_asset` and `add_loaded_labeled_asset`,
which is more error-prone.
## Solution
- Allow returning a (generic) error from `labeled_asset_scope`.
- This has the unfortunate side effect that closures which don't return
any errors need to A) return Ok at the end, B) need to specify an error
type (e.g., `()`).
---
## Showcase
```rust
// impl AssetLoader for MyLoader
let handle = load_context.labeled_asset_scope("MySubasset", |mut load_context| {
if !some_precondition {
return Err(ThingsDontMakeSenseError);
}
let handle = load_context.add_labeled_asset("MySubasset/Other", SomeOtherThing(456));
Ok(Something{ id: 123, handle })
})?;
```
788 B
788 B
title:
labeled_asset_scope can now return errors.
pull_requests: [19449]
labeled_asset_scope now returns a user-specified error type based on their closure. Previously,
users would need to fall back to begin_labeled_asset and add_loaded_labeled_asset to handle
errors, which is more error-prone. Consider migrating to use labeled_asset_scope if this was you!
However, labeled_asset_scope closures that don't return errors now needs to A) return Ok, and B)
specify an error type.
If your code previously looked like this:
labeled_asset_scope(label, |mut load_context| {
let my_asset = ...;
my_asset
});
You can migrate it to:
labeled_asset_scope::<_, ()>(label, |mut load_context| {
let my_asset = ...;
Ok(my_asset)
}).unwrap();