DioxusLabs/dioxus · error

Tried to access `err` on an Ok value

Error message

Tried to access `err` on an Ok value

What it means

Store<Result<T,E>>::err was consumed where the Err case was required, but the store currently holds Ok. The err() projection only yields a store when the result is an error, so assuming its presence panics.

Source

Thrown at packages/stores/src/impls/result.rs:127

    /// only track the shallow state of the `Result`. It will only cause a re-run if the `Result` could
    /// change from `Ok` to `Err` or vice versa.
    ///
    /// # Example
    /// ```rust, no_run
    /// use dioxus_stores::*;
    /// let store = use_store(|| Err::<(), u32>(42));
    /// match store.err() {
    ///     Some(err_store) => assert_eq!(err_store(), 42),
    ///     None => panic!("Expected Err"),
    /// }
    /// ```
    pub fn err(self) -> Option<MappedStore<E, Lens>>
    where
        Lens: Writable<Target = Result<T, E>> + 'static,
    {
        self.is_err().then(|| {
            let map: fn(&Result<T, E>) -> &E = |value| match value {
                Ok(_) => panic!("Tried to access `err` on an Ok value"),
                Err(e) => e,
            };
            let map_mut: fn(&mut Result<T, E>) -> &mut E = |value| match value {
                Ok(_) => panic!("Tried to access `err` on an Ok value"),
                Err(e) => e,
            };
            self.into_selector().child(1, map, map_mut).into()
        })
    }

    /// Transposes the `Store<Result<T, E>>` into a `Result<Store<T>, Store<E>>`. This will only track the
    /// shallow state of the `Result`. It will only cause a re-run if the `Result` could change from `Err` to
    /// `Ok` or vice versa.
    ///
    /// # Example
    /// ```rust, no_run
    /// use dioxus_stores::*;
    /// let store = use_store(|| Ok::<u32, ()>(42));

View on GitHub (pinned to 24f6a829df)

Solutions

1. The Result value is Ok. Match on the Result before accessing the err payload.

When it happens

Trigger: Thrown at packages/stores/src/impls/result.rs:127 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/1011774cb9c379cb. Report an issue: GitHub.