DioxusLabs/dioxus · error

Callback was manually dropped

Error message

Callback was manually dropped

What it means

Callback::call tried to call a callback whose inner closure slot was empty because the Callback was manually dropped (e.g. by Callback::drop or replacing it). The RefCell write returned None, indicating the callback no longer exists at call time.

Source

Thrown at packages/core/src/events.rs:532

            Location::caller(),
        );
        Self { callback, origin }
    }

    /// Call this callback with the appropriate argument type
    ///
    /// This borrows the callback using a RefCell. Recursively calling a callback will cause a panic.
    #[track_caller]
    pub fn call(&self, arguments: Args) -> Ret {
        if let Some(callback) = self.callback.write().as_mut() {
            let runtime = callback
                .runtime
                .upgrade()
                .expect("Callback was called after the runtime was dropped");
            let _guard = RuntimeGuard::new(runtime.clone());
            runtime.with_scope_on_stack(self.origin, || (callback.callback)(arguments))
        } else {
            panic!("Callback was manually dropped")
        }
    }

    /// Create a `impl FnMut + Copy` closure from the Closure type
    pub fn into_closure(self) -> impl FnMut(Args) -> Ret + Copy + 'static {
        move |args| self.call(args)
    }

    /// Forcibly drop the internal handler callback, releasing memory
    ///
    /// This will force any future calls to "call" to not doing anything
    pub fn release(&self) {
        self.callback.set(None);
    }

    /// Replace the function in the callback with a new one
    pub fn replace(&mut self, callback: Box<dyn FnMut(Args) -> Ret>) {
        let runtime = Runtime::current();

View on GitHub (pinned to 24f6a829df)

Solutions

1. The Callback was dropped before the event fired. Keep the callback alive (clone it) for as long as the event may be dispatched.

When it happens

Trigger: Thrown at packages/core/src/events.rs:532 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of DioxusLabs/dioxus@24f6a829df (2026-08-23). Data as JSON: /api/errors/f4451710c2f7543c. Report an issue: GitHub.