bevyengine/bevy · error · ReflectedRonDeserializeError::MissingReflectAsset

Attempted to load type

Error message

Attempted to load type "{0}", which does not have `ReflectAsset` in the type registry. Make sure to add `#[reflect(Asset)]` to your type

What it means

ReflectedRonDeserializeError::MissingReflectAsset is thrown when a RON asset contains a handle to an asset (e.g. #asset(...) or an Id) but the referenced type lacks ReflectAsset in the TypeRegistry. ReflectAsset is the type data that lets reflection resolve and load asset handles.

Solutions

Add #[reflect(Asset)] to the type's derive attribute: #[derive(Asset, Reflect)] #[reflect(Asset)]
Register the type: app.register_type::<T>() after adding the reflect(Asset) attribute
Ensure the asset's plugin (e.g. via bevy_asset add_asset) is loaded before the RON asset loads

Example fix

// before
#[derive(Asset, Reflect)]
struct MyMaterial { color: Color }

// after
#[derive(Asset, Reflect)]
#[reflect(Asset)]
struct MyMaterial { color: Color }

Defensive patterns

Strategy: validation

Validate before calling

fn has_reflect_asset<T: Asset + GetTypeRegistration>(app: &App) -> bool {
    let reg = app.world().resource::<AppTypeRegistry>().0.read();
    reg.get(TypeId::of::<T>()).map_or(false, |r| r.data::<ReflectAsset>().is_some())
}

Type guard

fn has_reflect_asset(registry: &TypeRegistry, ty: TypeId) -> bool {
    registry.get(ty).map_or(false, |r| r.data::<ReflectAsset>().is_some())
}

Prevention

Always add #[reflect(Asset)] to custom asset types
Register asset types before asset loads are triggered
Keep the type registration inside the asset's plugin

When it happens

Trigger: Loading a .ron file that references a Bevy asset handle for type T where T implements Asset and Reflect but was never annotated #[reflect(Asset)] / registered with ReflectAsset type data.

Common situations: A struct field of type Handle<T> or AssetId<T> in a RON asset where the plugin for T didn't register the asset reflection; custom asset types missing #[reflect(Asset)].

Related errors

AI-assisted analysis of bevyengine/bevy@a62cce8c05 (2026-09-19). Data as JSON: /api/errors/daa69e0aa236d9fc. Report an issue: GitHub.

Appendix: source

Thrown at crates/bevy_asset/src/common_loaders/ron.rs:459

}

/// An error type for RON loading.
#[derive(Error, Debug)]
pub enum RonDeserializeError {
    #[error(transparent)]
    IoError(#[from] std::io::Error),
    #[error(transparent)]
    RonSpan(#[from] ron::de::SpannedError),
}

/// An error type for RON loading using reflection.
#[derive(Error, Debug)]
pub enum ReflectedRonDeserializeError {
    #[error(transparent)]
    Ron(#[from] RonDeserializeError),
    #[error("Attempted to load type \"{0}\", which does not have `ReflectFromReflect` in the type registry. This may occur for types that have opted-out of `FromReflect`")]
    MissingReflectFromReflect(&'static str),
    #[error("Attempted to load type \"{0}\", which does not have `ReflectAsset` in the type registry. Make sure to add `#[reflect(Asset)]` to your type")]
    MissingReflectAsset(&'static str),
}

/// An error type for RON saving.
#[derive(Error, Debug)]
pub enum RonSerializeError {
    #[error(transparent)]
    IoError(#[from] std::io::Error),
    #[error(transparent)]
    Ron(#[from] ron::Error),
}

/// An error type for RON saving using reflection.
#[derive(Error, Debug)]
pub enum ReflectedRonSerializeError {
    #[error(
        "Expected the root LoadedUntypedHandle to hold a handle to its subasset, but it did not have such a subasset"
    )]

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