Multiple Validators & Error Handling

A field can have more than one validator. After deriving Koruma, calling validate() runs all configured validators and returns Result<(), Errors>. On failure, the generated Errors type provides strongly typed field accessors, and each field error group exposes accessors for the individual validators that failed.

if let Err(errors) = item.validate() {
    for failed in errors.age().all() {
        println!("age validator: {}", failed);
    }

    for failed in errors.name().all() {
        println!("name validator: {}", failed);
    }
}

This pattern is useful when a field has multiple rules and you want to show every failure instead of only the first one. The order of execution follows the order in which validators are listed in the #[koruma(...)] attribute, and all configured validators are evaluated.

You can customise error rendering by implementing Display for validators, or localise errors with es-fluent and KorumaAllFluent, which is covered in the next chapter.