bevyengine/bevy · error · ResourceFetchError::NoResourceAccess

Cannot get access to the resource with ID {0:?} in the world

Error message

Cannot get access to the resource with ID {0:?} in the world as it conflicts with an on going operation.

What it means

ResourceFetchError::InUse / conflict: access to the resource by ComponentId was refused because it conflicts with an ongoing operation on the world (e.g. the resource is already exclusively borrowed), a sentinel guard for concurrent/aliased access.

Source

Thrown at crates/bevy_ecs/src/world/error.rs:74

    and want to handle this error gracefully, consider using `EntityCommands::queue_handled` or `queue_silenced`."
    )]
    NotSpawned(#[from] EntityNotSpawnedError),
    /// The entity with the given ID was requested mutably more than once.
    #[error("The entity with ID {0} was requested mutably more than once")]
    AliasedMutability(Entity),
}

/// An error that occurs when getting a resource of a given type in a world.
#[derive(thiserror::Error, Debug, Clone, Copy, PartialEq, Eq)]
pub enum ResourceFetchError {
    /// The resource has never been initialized or registered with the world.
    #[error("The resource has never been initialized or registered with the world. Did you forget to add it using `app.insert_resource` / `app.init_resource`?")]
    NotRegistered,
    /// The resource with the given [`ComponentId`] does not currently exist in the world.
    #[error("The resource with ID {0:?} does not currently exist in the world.")]
    DoesNotExist(ComponentId),
    /// Cannot get access to the resource with the given [`ComponentId`] in the world as it conflicts with an on going operation.
    #[error("Cannot get access to the resource with ID {0:?} in the world as it conflicts with an on going operation.")]
    NoResourceAccess(ComponentId),
    /// Tried to mutably fetch an immutable resource.
    #[error("Tried to mutably fetch resource with ID {0:?}, which is immutable")]
    Immutable(ComponentId),
}

#[cfg(test)]
mod tests {
    use crate::{
        prelude::*,
        system::{command::trigger, RunSystemOnce},
    };

    // Inspired by https://github.com/bevyengine/bevy/issues/19623
    #[test]
    fn fixing_panicking_entity_commands() {
        #[derive(EntityEvent)]
        struct Kill(Entity);

View on GitHub (pinned to 396ca72708)

Solutions

1. Ensure the previous borrow of the resource has ended before fetching again
2. Scope resource access tightly so borrows are dropped
3. Retry or defer the fetch until the conflicting operation completes

When it happens

Trigger: Thrown at crates/bevy_ecs/src/world/error.rs:74 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/43535f22d96ec6bb. Report an issue: GitHub.