bevyengine/bevy · error · ReflectedRonSerializeError::MissingReflectFromPtr

Subasset type does not have ReflectFromPtr registered in…

Error message

Subasset type does not have ReflectFromPtr registered in its type data

What it means

ReflectedRonSerializeError::MissingReflectFromPtr is thrown when the subasset type's registry entry lacks the ReflectFromPtr type data. During serialization Bevy holds the value behind a raw pointer and needs ReflectFromPtr to safely convert it to a &dyn Reflect of the concrete type.

Solutions

1. Register the type through app.register_type::<T>() which attaches ReflectFromPtr automatically
2. If building registry entries manually, add registry.get_mut(TypeId).insert(ReflectFromPtr::from_type::<T>())
3. Re-derive Reflect via the standard macro so required type data is generated

Example fix

// before
let mut registry = TypeRegistry::default();
registry.register::<T>();

// after
let mut registry = TypeRegistry::default();
registry.register::<T>();
registry.get_mut(TypeId::of::<T>()).unwrap().insert(ReflectFromPtr::from_type::<T>());

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

When it happens

Trigger: Saving a reflected RON asset for a type that was registered (register_type) but whose ReflectFromPtr type data is missing — e.g. registration done without the standard derive/registration macro flow.

Common situations: Manually building TypeRegistry entries and skipping type data; types registered via get_type_registry with partial registration.

Related errors

• Subasset type was not registered in the TypeRegistry…
• Attempted to load type
• Attempted to load type
• Could not parse RON
• Error while trying to read the world file

AI-assisted analysis of bevyengine/bevy@a62cce8c05 (2026-09-19). Data as JSON: /api/errors/00ce81d3a628c9a8. Report an issue: GitHub.

Appendix: source

Thrown at crates/bevy_asset/src/common_loaders/ron.rs:481

/// 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"
    )]
    MissingSubasset,
    #[error("Subasset type was not registered in the TypeRegistry. Ensure your subasset's type implements Reflect (and if it's generic it needs to be manually registered)")]
    ValueNotReflect,
    #[error("Subasset type does not have ReflectFromPtr registered in its type data")]
    MissingReflectFromPtr,
    #[error(transparent)]
    Ron(#[from] RonSerializeError),
}

#[cfg(test)]
mod tests {
    use std::path::Path;

    use alloc::{string::String, vec};

    use bevy_ecs::reflect::AppTypeRegistry;
    use bevy_reflect::{Reflect, TypePath};
    use bevy_tasks::{futures::check_ready, IoTaskPool};
    use serde::{Deserialize, Serialize};

    use crate::{
        common_loaders::ron::{

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