Trait Config

pub trait Config: Config + Config<RuntimeEvent: From<Event<Self>>> {
    type RelayChainOrigin: EnsureOrigin<Self::RuntimeOrigin>;
    type AHStakingInterface: AHStakingInterface<AccountId = Self::AccountId>;
    type SendToRelayChain: SendToRelayChain<AccountId = Self::AccountId>;
    type MaxValidatorSetRetries: Get<u32>;
    type ValidatorSetExportSession: Get<SessionIndex>;
}

Configuration trait of this pallet.

The main purpose of this trait is to act as an interface between this pallet and the runtime in which it is embedded in. A type, function, or constant in this trait is essentially left to be configured by the runtime that includes this pallet.

Consequently, a runtime that wants to include this pallet must implement this trait.

Required Associated Types

type RelayChainOrigin: EnsureOrigin<Self::RuntimeOrigin>

An origin type that allows us to be sure a call is being dispatched by the relay chain.

It be can be configured to something like Root or relay chain or similar.

type AHStakingInterface: AHStakingInterface<AccountId = Self::AccountId>

Our communication handle to the local staking pallet.

type SendToRelayChain: SendToRelayChain<AccountId = Self::AccountId>

Our communication handle to the relay chain.

type MaxValidatorSetRetries: Get<u32>

Maximum number of times that we retry sending a validator set to RC, after which, if sending still fails, we emit an UnexpectedKind::ValidatorSetDropped event and drop it.

type ValidatorSetExportSession: Get<SessionIndex>

The end session index within an era post which we export validator set to RC.

This is a 1-indexed session number relative to the era start:

• 0 = export immediately when received from staking pallet
• 1 = export at end of first session of era
• 5 = export at end of 5th session of era (for 6-session eras)

The validator set is placed in OutgoingValidatorSet when election completes in pallet-staking-async. The XCM message is sent when BOTH conditions met:

1. Current session offset >= ValidatorSetExportSession
2. OutgoingValidatorSet exists (validator set buffered)

Setting to 0 bypasses the session check and exports immediately.

Example: With SessionsPerEra=6 and ValidatorSetExportSession=4:

• Session 0: Election completes → validator set buffered in OutgoingValidatorSet
• Sessions 1-4: Buffered (session offset < 5)
• End of Session 4 and start of Session 5: Export triggered.

Must be < SessionsPerEra.

Dyn Compatibility

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety", so this trait is not object safe.

Implementors