diesel-rs/diesel · error

Field not found

Error message

Field not found

What it means

Runtime panic from the Index<&str> impl for DynamicRow<NamedField<I>> in diesel_dynamic_schema. The row is indexed by field name via a linear search over the named values; when no field's name equals the requested key the Option is unwrapped with expect, so a typo'd or absent column name panics with this generic sentinel. Fix: index with a name that exists in the row, or look up the field fallibly before indexing.

Solutions

1. Use an existing field name from the row
2. Inspect the row's field list before indexing
3. Add the missing field to the dynamic schema

When it happens

Trigger: Thrown at diesel_dynamic_schema/src/dynamic_value.rs:530 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of diesel-rs/diesel@6fa6ed01b2 (2026-09-07). Data as JSON: /api/errors/44a853ed73d9c6ca. Report an issue: GitHub.

Appendix: source

Thrown at diesel_dynamic_schema/src/dynamic_value.rs:530

        &self.values[index]
    }
}

impl<I> IndexMut<usize> for DynamicRow<I> {
    fn index_mut(&mut self, index: usize) -> &mut Self::Output {
        &mut self.values[index]
    }
}

impl<'a, I> Index<&'a str> for DynamicRow<NamedField<I>> {
    type Output = I;

    fn index(&self, field_name: &'a str) -> &Self::Output {
        self.values
            .iter()
            .find(|f| f.name == field_name)
            .map(|f| &f.value)
            .expect("Field not found")
    }
}

impl<'a, I> IndexMut<&'a str> for DynamicRow<NamedField<I>> {
    fn index_mut(&mut self, field_name: &'a str) -> &mut Self::Output {
        self.values
            .iter_mut()
            .find(|f| f.name == field_name)
            .map(|f| &mut f.value)
            .expect("Field not found")
    }
}

impl<'a, I> Index<&'a String> for DynamicRow<NamedField<I>> {
    type Output = I;

    fn index(&self, field_name: &'a String) -> &Self::Output {
        self.index(field_name as &str)

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