{"record":{"id":"fff5630a60593b45","repo":"bevyengine/bevy","slug":"draw-function-not-found-for","errorCode":null,"errorMessage":"Draw function {} not found for {}","messagePattern":"Draw function (.+?) not found for (.+?)","errorType":"panic","errorClass":null,"httpStatus":null,"severity":"critical","filePath":"crates/bevy_render/src/render_phase/draw.rs","lineNumber":101,"sourceCode":"    /// Retrieves the [`Draw`] function corresponding to the `id` mutably.\n    pub fn get_mut(&mut self, id: DrawFunctionId) -> Option<&mut dyn Draw<P>> {\n        self.draw_functions.get_mut(id.0 as usize).map(|f| &mut **f)\n    }\n\n    /// Retrieves the id of the [`Draw`] function corresponding to their associated type `T`.\n    pub fn get_id<T: 'static>(&self) -> Option<DrawFunctionId> {\n        self.indices.get(&TypeId::of::<T>()).copied()\n    }\n\n    /// Retrieves the id of the [`Draw`] function corresponding to their associated type `T`.\n    ///\n    /// Fallible wrapper for [`Self::get_id()`]\n    ///\n    /// ## Panics\n    /// If the id doesn't exist, this function will panic.\n    pub fn id<T: 'static>(&self) -> DrawFunctionId {\n        self.get_id::<T>().unwrap_or_else(|| {\n            panic!(\n                \"Draw function {} not found for {}\",\n                core::any::type_name::<T>(),\n                core::any::type_name::<P>()\n            )\n        })\n    }\n}\n\n/// Stores all draw functions for the [`PhaseItem`] type hidden behind a reader-writer lock.\n///\n/// To access them the [`DrawFunctions::read`] and [`DrawFunctions::write`] methods are used.\n#[derive(Resource)]\npub struct DrawFunctions<P: PhaseItem> {\n    internal: RwLock<DrawFunctionsInternal<P>>,\n}\n\nimpl<P: PhaseItem> Default for DrawFunctions<P> {\n    fn default() -> Self {","sourceCodeStart":83,"sourceCodeEnd":119,"githubUrl":"https://github.com/bevyengine/bevy/blob/396ca727080776bd313bb892423b7d94e03b81b4/crates/bevy_render/src/render_phase/draw.rs#L83-L119","documentation":"DrawFunctions<P>::id::<T>() (draw.rs:99) panics with 'Draw function {T} not found for {P}' when no Draw function of type T has been registered for the phase item type P. It is the panicking counterpart of get_id::<T>(), which returns Option, and its doc explicitly says it panics if the id doesn't exist.","triggerScenarios":"Calling draw_functions.read().id::<T>() where T (typically a RenderCommandState wrapping your RenderCommand) was never added via app.add_render_command::<P, T>() or DrawFunctions::write().add(..) before the call.","commonSituations":"Custom PhaseItems: a plugin queues items using a DrawFunctionId from id::<DrawX>() but forgot app.add_render_command::<CustomPhaseItem, DrawX>(); initialization order where ids are requested before registration; refactors that changed the command type so registered and requested types differ.","solutions":["Register the draw function before first use: app.add_render_command::<CustomPhaseItem, DrawCustom>() in your plugin's build().","Use get_id::<T>() and handle None gracefully instead of the panicking id().","Ensure the plugin that initializes DrawFunctions<P> and registers commands is added before the code that requests ids (check plugin ordering)."],"exampleFix":"// before\nlet draw_id = draw_functions.read().id::<DrawCustomPhaseItemCommands>(); // panics if unregistered\n\n// after\nlet draw_functions = draw_functions.read();\nlet Some(draw_id) = draw_functions.get_id::<DrawCustomPhaseItemCommands>() else {\n    error!(\"DrawCustomPhaseItemCommands not registered for this phase yet\");\n    return;\n};","handlingStrategy":"validation","validationCode":"let draw_functions = draw_functions.read();\nif draw_functions.get_id::<DrawCustom>().is_none() {\n    // register before first use instead of letting id() panic\n    error!(\"DrawCustom not registered for this phase\");\n    return;\n}","typeGuard":null,"tryCatchPattern":null,"preventionTips":["Register all render commands in your plugin's build() via add_render_command before anything queries ids.","Prefer get_id() over id() in any code that can run before registration.","Add a smoke test that builds the app and renders one frame to catch registration-order issues."],"tags":["bevy","draw-function","phase-item","panic","registration"],"backgroundTag":"unregistered-function-lookup","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"}