{"record":{"id":"51b110006023199e","repo":"FyroxEngine/Fyrox","slug":"attempt-to-get-reference-to-resource-data-while-it-51b110","errorCode":null,"errorMessage":"Attempt to get reference to resource data while it is loading!","messagePattern":"Attempt to get reference to resource data while it is loading!","errorType":"panic","errorClass":null,"httpStatus":null,"severity":"critical","filePath":"fyrox-resource/src/lib.rs","lineNumber":639,"sourceCode":"            ResourceState::Ok { ref data } => (data.inner_ref() as &dyn Any)\n                .downcast_ref()\n                .expect(\"Type mismatch!\"),\n        }\n    }\n}\n\nimpl<T> DerefMut for ResourceDataRef<'_, T>\nwhere\n    T: TypedResourceData,\n{\n    fn deref_mut(&mut self) -> &mut Self::Target {\n        let header = &mut *self.guard;\n        match header.state {\n            ResourceState::Unloaded => {\n                panic!(\"Attempt to get reference to resource data while it is unloaded!\")\n            }\n            ResourceState::Pending { .. } => {\n                panic!(\"Attempt to get reference to resource data while it is loading!\")\n            }\n            ResourceState::LoadError { .. } => {\n                panic!(\"Attempt to get reference to resource data which failed to load!\")\n            }\n            ResourceState::Ok { ref mut data, .. } => (data.inner_mut() as &mut dyn Any)\n                .downcast_mut()\n                .expect(\"Type mismatch!\"),\n        }\n    }\n}\n\n/// Collects all resources used by a given entity. Internally, it uses reflection to iterate over\n/// each field of every descendant sub-object of the entity. This function could be used to collect\n/// all resources used by an object, which could be useful if you're building a resource dependency\n/// analyzer.\npub fn collect_used_resources(\n    entity: &dyn Reflect,\n    resources_collection: &mut FxHashSet<UntypedResource>,","sourceCodeStart":621,"sourceCodeEnd":657,"githubUrl":"https://github.com/FyroxEngine/Fyrox/blob/76c91aad8eca488ce527b1af707be8b3b24ad72d/fyrox-resource/src/lib.rs#L621-L657","documentation":"Fyrox resources are shared handles whose data is guarded by ResourceState. deref_mut() must only hand out &mut T when the resource is in ResourceState::Ok. If the resource is still Pending (being loaded asynchronously), the guard panics instead of returning a reference to uninitialized or in-flight data.","triggerScenarios":"Calling deref_mut() (e.g. via DerefMut on ResourceDataRef or explicit data access) on a resource whose state() is ResourceState::Pending — i.e. the resource was requested with request_resource/try_data_ref before its async load finished.","commonSituations":"Accessing a texture/model/sound buffer on the same frame it was requested; game code that dereferences resources in init() before the asset loader thread completes; blocking on data only in one thread while another thread mutates through deref_mut during load.","solutions":["Wait until the resource is loaded before mutating: loop on resource.state() or use resource.clone().await / event-driven resource loading (ResourceEventBindings) before calling deref_mut.","Check state explicitly: only enter the mutation path when matches!(resource.state(), ResourceState::Ok{..}).","Use try_data_ref / data_ref-style non-panicking accessors where available and handle the None/loading case.","Ensure the resource actually has a registered loader so it transitions to Ok instead of staying in a load pipeline; check logs for load errors."],"exampleFix":"// before\nlet mut texture_data = texture.data_mut(); // panics while loading\ntexture_data.set_minification_filter(FilterMode::Trilinear);\n// after\nif let ResourceState::Ok(_) = &*resource.state() {\n    let mut texture_data = resource.data_mut();\n    texture_data.set_minification_filter(FilterMode::Trilinear);\n}","handlingStrategy":"validation","validationCode":"fn is_loaded<T: ResourceData>(r: &Resource<T>) -> bool {\n    matches!(&*r.state(), ResourceState::Ok { .. })\n}\n// call r.data_mut() only when is_loaded(&r)","typeGuard":"fn loaded_data<T: ResourceData>(r: &Resource<T>) -> Option<ResourceDataRef<'_, T>> {\n    match &*r.state() { ResourceState::Ok { .. } => Some(r.data_ref()), _ => None }\n}","tryCatchPattern":null,"preventionTips":["Never dereference resource data on the same frame you request it; use resource events or await load completion.","Centralize data access behind a helper that checks state first.","Watch logs for load pipeline warnings indicating Pending resources.","Prefer try_data_ref-style APIs in game update loops."],"tags":["rust","panic","async-loading","resource-state","fyrox"],"backgroundTag":"invalid-state-transition","analyzedSha":"76c91aad8eca488ce527b1af707be8b3b24ad72d","analyzedAt":"2026-09-10T16:04:01.633Z","contentChangedAt":"2026-09-10T16:04:01.633Z","schemaVersion":2},"datasetVersion":"2026-09-16T09:17:16.951Z"}