bevyengine/bevy · error

Requested resource {} does not exist in the `World`.

Error message

Requested resource {} does not exist in the `World`.
                Did you forget to add it using `app.insert_resource` / `app.init_resource`?
                Resources are also implicitly added via `app.add_message`,
                and can be added by plugins.

What it means

Error "Requested resource {} does not exist in the `World`. Did you forget to add it using `app.insert_resource` / `app.init_resource`? Resources are also implicitly added via `app.add_message`, and can be added by plugins." thrown in bevyengine/bevy.

Source

Thrown at crates/bevy_ecs/src/world/deferred_world.rs:466

        &mut self,
        state: &'s mut QueryState<D, F>,
    ) -> Query<'_, 's, D, F> {
        // SAFETY: We have mutable access to the entire world
        unsafe { state.query_unchecked(self.world) }
    }

    /// Gets a mutable reference to the resource of the given type
    ///
    /// # Panics
    ///
    /// Panics if the resource does not exist.
    /// Use [`get_resource_mut`](DeferredWorld::get_resource_mut) instead if you want to handle this case.
    #[inline]
    #[track_caller]
    pub fn resource_mut<R: Resource<Mutability = Mutable>>(&mut self) -> Mut<'_, R> {
        match self.get_resource_mut() {
            Some(x) => x,
            None => panic!(
                "Requested resource {} does not exist in the `World`.
                Did you forget to add it using `app.insert_resource` / `app.init_resource`?
                Resources are also implicitly added via `app.add_message`,
                and can be added by plugins.",
                DebugName::type_name::<R>()
            ),
        }
    }

    /// Gets a mutable reference to the resource of the given type if it exists
    #[inline]
    pub fn get_resource_mut<R: Resource<Mutability = Mutable>>(&mut self) -> Option<Mut<'_, R>> {
        // SAFETY: &mut self ensure that there are no outstanding accesses to the resource
        unsafe { self.world.get_resource_mut() }
    }

    /// Gets a mutable reference to the non-send data of the given type, if it exists.
    ///

View on GitHub (pinned to 396ca72708)

Solutions

1. Add the resource first: app.insert_resource(...) / app.init_resource::<R>()
2. Use get_resource_mut().expect(...) or match on Option to control the failure yourself
3. Use get_resource_or_insert_with to lazily create it

When it happens

Trigger: Thrown at crates/bevy_ecs/src/world/deferred_world.rs:466 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of bevyengine/bevy@396ca72708 (2026-08-20). Data as JSON: /api/errors/6dd727c0ab0e39dd. Report an issue: GitHub.