bevyengine/bevy · error

{err}

Error message

{err}

What it means

Panic in tuple_apply (used by PartialReflect::apply for tuples): the error from tuple_try_apply — typically that b is not a reflected Tuple (wrong ReflectKind or arity mismatch) — is unwrapped and panics. Apply only reflected tuples; use tuple_try_apply to handle errors.

Source

Thrown at crates/bevy_reflect/src/tuple.rs:411

impl<'a> IntoIterator for &'a DynamicTuple {
    type Item = &'a dyn PartialReflect;
    type IntoIter = TupleFieldIter<'a>;

    fn into_iter(self) -> Self::IntoIter {
        self.iter_fields()
    }
}

/// Applies the elements of `b` to the corresponding elements of `a`.
///
/// # Panics
///
/// This function panics if `b` is not a tuple.
#[inline]
pub fn tuple_apply<T: Tuple>(a: &mut T, b: &dyn PartialReflect) {
    if let Err(err) = tuple_try_apply(a, b) {
        panic!("{err}");
    }
}

/// Tries to apply the elements of `b` to the corresponding elements of `a` and
/// returns a Result.
///
/// # Errors
///
/// This function returns an [`ApplyError::MismatchedKinds`] if `b` is not a tuple or if
/// applying elements to each other fails.
#[inline]
pub fn tuple_try_apply<T: Tuple>(a: &mut T, b: &dyn PartialReflect) -> Result<(), ApplyError> {
    let tuple = b.reflect_ref().as_tuple()?;

    for (i, value) in tuple.iter_fields().enumerate() {
        if let Some(v) = a.field_mut(i) {
            v.try_apply(value)?;
        }

View on GitHub (pinned to 8d743eb7dc)

Solutions

1. Use tuple_try_apply and handle the returned ApplyError
2. Ensure the applied value reflects as a Tuple with compatible field types

When it happens

Trigger: Thrown at crates/bevy_reflect/src/tuple.rs:411 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of bevyengine/bevy@8d743eb7dc (2026-08-20). Data as JSON: /api/errors/48a6de708f0105d6. Report an issue: GitHub.