What does this validator error mean? "Validator with index 0 is disabled and should not be attempting to author blocks."

Question

So this happened when I created a new validator and injected their session keys into my node. Then I proceeded to call forceNewEra from the staking module as sudo, and I am greeted with this :

Proposing failed: ClientImport("RuntimeApiError(Application(Execution(RuntimePanicked("Validator with index 0 is disabled and should not be attempting to author blocks."))))")

What does it mean?

Answer 1

This error appears when checking a validator against the DisabledValidators hook.

This is most commonly implemented by the Session pallet, which maintains a storage list of validators that should be disabled:

    /// Indices of disabled validators.
    ///
    /// The vec is always kept sorted so that we can find whether a given validator is
    /// disabled using binary search. It gets cleared when `on_session_ending` returns
    /// a new set of identities.
    #[pallet::storage]
    #[pallet::getter(fn disabled_validators)]
    pub type DisabledValidators<T> = StorageValue<_, Vec<u32>, ValueQuery>;

This error means whichever validator you are running into an issue with is part of this DisabledValidators list, or whatever you have implemented for the DisabledValidators hook.

If you don't want this behavior, use () for the DisabledValidators hook.