{"record":{"id":"19da023c48471477","repo":"bevyengine/bevy","slug":"error-while-trying-to-read-the-world-file-0","errorCode":null,"errorMessage":"Error while trying to read the world file: {0}","messagePattern":"Error while trying to read the world file: (.+?)","errorType":"exception","errorClass":"WorldAssetLoaderError","httpStatus":null,"severity":"error","filePath":"crates/bevy_world_serialization/src/world_asset_loader.rs","lineNumber":42,"sourceCode":"    type_registry: TypeRegistryArc,\n}\n\nimpl FromWorld for WorldAssetLoader {\n    fn from_world(world: &mut World) -> Self {\n        let type_registry = world.resource::<AppTypeRegistry>();\n        WorldAssetLoader {\n            type_registry: type_registry.0.clone(),\n        }\n    }\n}\n\n/// Possible errors that can be produced by [`WorldAssetLoader`]\n#[cfg(feature = \"serialize\")]\n#[non_exhaustive]\n#[derive(Debug, Error)]\npub enum WorldAssetLoaderError {\n    /// An [IO Error](std::io::Error)\n    #[error(\"Error while trying to read the world file: {0}\")]\n    Io(#[from] std::io::Error),\n    /// A [RON Error](ron::error::SpannedError)\n    #[error(\"Could not parse RON: {0}\")]\n    RonSpannedError(#[from] ron::error::SpannedError),\n}\n\n#[cfg(feature = \"serialize\")]\nimpl AssetLoader for WorldAssetLoader {\n    type Asset = DynamicWorld;\n    type Settings = ();\n    type Error = WorldAssetLoaderError;\n\n    async fn load(\n        &self,\n        reader: &mut dyn Reader,\n        _settings: &(),\n        load_context: &mut LoadContext<'_>,\n    ) -> Result<Self::Asset, Self::Error> {","sourceCodeStart":24,"sourceCodeEnd":60,"githubUrl":"https://github.com/bevyengine/bevy/blob/396ca727080776bd313bb892423b7d94e03b81b4/crates/bevy_world_serialization/src/world_asset_loader.rs#L24-L60","documentation":"The WorldAssetLoader (bevy_world_serialization) deserializes a saved Bevy World from RON. Any std::io::Error raised while reading the asset's bytes is wrapped into WorldAssetLoaderError::Io with the message \"Error while trying to read the world file: {0}\". This is the IO-layer failure of a .world asset load; note that a missing file usually surfaces earlier as an asset-reader error, so this variant typically means the file was found but reading it failed.","triggerScenarios":"Loading a truncated or zero-byte .world file; a file that becomes unreadable mid-load (permissions, disk, network filesystem hiccup with an async file source); custom AssetSource readers returning io::Error during read.","commonSituations":"World save files corrupted by interrupted writes or crashes; deploy pipelines truncating assets; cloud/streamed asset sources with flaky IO; partial downloads when serving worlds over HTTP.","solutions":["Check the file exists, is non-empty, and is readable by the process (permissions, size on disk).","If the save was interrupted, regenerate or restore the .world file from a backup or re-export from the editor.","Handle load failure gracefully: watch the asset's LoadState and show recovery UI instead of assuming success.","For network sources, retry the load once after an Io error — transient reader failures are common.","Write saves atomically (temp file + rename) so interrupted saves never leave truncated files."],"exampleFix":"// before\nlet world: Handle<WorldAsset> = asset_server.load(\"worlds/level1.world\"); // truncated file -> Io error\n\n// after: validate before relying on it, and regenerate broken saves\nif std::fs::metadata(\"assets/worlds/level1.world\").map(|m| m.len() < 16).unwrap_or(true) {\n    warn!(\"level1.world missing or truncated — restoring default\");\n    std::fs::copy(\"assets/worlds/default.world\", \"assets/worlds/level1.world\");\n}","handlingStrategy":"try-catch","validationCode":"// cheap pre-flight before requesting the asset\nfn world_file_readable(path: &std::path::Path) -> bool {\n    std::fs::metadata(path).map(|m| m.len() > 0).unwrap_or(false)\n}","typeGuard":null,"tryCatchPattern":"use bevy_asset::LoadState;\n\nmatch asset_server.get_load_state(&world_handle) {\n    Some(LoadState::Failed(err)) => {\n        if let bevy_asset::AssetLoadError::AssetLoaderError(loader_err) = &*err {\n            if let Some(io_err) = loader_err.error.downcast_ref::<WorldAssetLoaderError>() {\n                error!(\"world asset failed: {io_err}\"); // Io(e) or RonSpannedError(e)\n            }\n        }\n        // recover: restore a backup, show an error screen, etc.\n    }\n    _ => {}\n}","preventionTips":["Write save files atomically (temp + rename) so truncated files never exist.","Check file size/permissions before relying on a load in tooling.","Keep backups of world saves and expose a 'restore default world' path.","Retry once on transient IO from network asset sources."],"tags":["rust","bevy","assets","serialization","io","world"],"backgroundTag":"file-read-io-error","analyzedSha":"396ca727080776bd313bb892423b7d94e03b81b4","analyzedAt":"2026-08-20T16:12:39.808Z","contentChangedAt":"2026-08-20T16:12:39.808Z","schemaVersion":2},"datasetVersion":"2026-09-14T00:17:10.932Z"}