bevyengine/bevy · error

Joining queries initialized on different worlds is not allow

Error message

Joining queries initialized on different worlds is not allowed.

What it means

Panic from QueryState::join_filtered: the two QueryStates being joined were created against different Worlds (their world_id fields differ). A joined query's tables/archetypes are only valid relative to one world, so this guard rejects cross-world joins as unsound.

Source

Thrown at crates/bevy_ecs/src/query/state.rs:813

    /// Use this to combine two queries. The data accessed will be the intersection
    /// of archetypes included in both queries.
    ///
    /// ## Panics
    ///
    /// Will panic if `NewD` or `NewF` requires accesses not in `Q` or `OtherQ`.
    pub fn join_filtered<
        'a,
        OtherD: QueryData,
        OtherF: QueryFilter,
        NewD: SingleEntityQueryData,
        NewF: QueryFilter,
    >(
        &self,
        world: impl Into<UnsafeWorldCell<'a>>,
        other: &QueryState<OtherD, OtherF>,
    ) -> QueryState<NewD, NewF> {
        if self.world_id != other.world_id {
            panic!("Joining queries initialized on different worlds is not allowed.");
        }

        let world = world.into();

        self.validate_world(world.id());

        let mut component_access = FilteredAccess::default();
        let mut new_fetch_state = NewD::get_state(world.components())
            .expect("Could not create fetch_state, Please initialize all referenced components before transmuting.");
        let new_filter_state = NewF::get_state(world.components())
            .expect("Could not create filter_state, Please initialize all referenced components before transmuting.");

        let mut joined_component_access = self.component_access.clone();
        joined_component_access.extend(&other.component_access);

        if D::IS_READ_ONLY && self.component_access.access().has_any_write()
            || OtherD::IS_READ_ONLY && other.component_access.access().has_any_write()
        {

View on GitHub (pinned to 396ca72708)

Solutions

1. Recreate one of the QueryStates against the same World before joining
2. Initialize both states from the target world (e.g. world.query::<Q>())
3. Avoid persisting QueryState across world instances

When it happens

Trigger: Thrown at crates/bevy_ecs/src/query/state.rs:813 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/3b1d6646b66aabed. Report an issue: GitHub.