lib.rs

	/// When updating this storage item, you must also update the `CounterForValidators`.
	#[pallet::storage]
	#[pallet::getter(fn validators)]
	pub type Validators<T: Config> = StorageMap<_, Twox64Concat, T::AccountId, ValidatorPrefs, ValueQuery>;

	/// A tracker to keep count of the number of items in the `Validators` map.
	#[pallet::storage]
	pub type CounterForValidators<T> = StorageValue<_, u32, ValueQuery>;

	/// The maximum validator count before we stop allowing new validators to join.
	///
	/// When this value is not set, no limits are enforced.
	#[pallet::storage]
	pub type MaxValidatorsCount<T> = StorageValue<_, u32, OptionQuery>;

	/// The map from nominator stash key to the set of stash keys of all validators to nominate.
	///
	/// When updating this storage item, you must also update the `CounterForNominators`.
	#[pallet::storage]
	#[pallet::getter(fn nominators)]
	pub type Nominators<T: Config> = StorageMap<_, Twox64Concat, T::AccountId, Nominations<T::AccountId>>;

	/// A tracker to keep count of the number of items in the `Nominators` map.
	#[pallet::storage]
	pub type CounterForNominators<T> = StorageValue<_, u32, ValueQuery>;

	/// The maximum nominator count before we stop allowing new validators to join.
	///
	/// When this value is not set, no limits are enforced.
	#[pallet::storage]
	pub type MaxNominatorsCount<T> = StorageValue<_, u32, OptionQuery>;

	/// The current era index.
	///
	/// This is the latest planned era, depending on how the Session pallet queues the validator
	/// set, it might be active or not.
	#[pallet::storage]
	#[pallet::getter(fn current_era)]
	pub type CurrentEra<T> = StorageValue<_, EraIndex>;

	/// The active era information, it holds index and start.
	///
	/// The active era is the era being currently rewarded. Validator set of this era must be
	/// equal to [`SessionInterface::validators`].
	#[pallet::storage]
	#[pallet::getter(fn active_era)]
	pub type ActiveEra<T> = StorageValue<_, ActiveEraInfo>;

	/// The session index at which the era start for the last `HISTORY_DEPTH` eras.
	///
	/// Note: This tracks the starting session (i.e. session index when era start being active)
	/// for the eras in `[CurrentEra - HISTORY_DEPTH, CurrentEra]`.
	#[pallet::storage]
	#[pallet::getter(fn eras_start_session_index)]
	pub type ErasStartSessionIndex<T> = StorageMap<_, Twox64Concat, EraIndex, SessionIndex>;

	/// Exposure of validator at era.
	///
	/// This is keyed first by the era index to allow bulk deletion and then the stash account.
	///
	/// Is it removed after `HISTORY_DEPTH` eras.
	/// If stakers hasn't been set or has been removed then empty exposure is returned.
	#[pallet::storage]
	#[pallet::getter(fn eras_stakers)]
	pub type ErasStakers<T: Config> = StorageDoubleMap<
		_,
		Twox64Concat, EraIndex,
		Twox64Concat, T::AccountId,
		Exposure<T::AccountId, BalanceOf<T>>,
		ValueQuery,
	>;

	/// Clipped Exposure of validator at era.
	///
	/// This is similar to [`ErasStakers`] but number of nominators exposed is reduced to the
	/// `T::MaxNominatorRewardedPerValidator` biggest stakers.
	/// (Note: the field `total` and `own` of the exposure remains unchanged).
	/// This is used to limit the i/o cost for the nominator payout.
	///
	/// This is keyed fist by the era index to allow bulk deletion and then the stash account.
	///
	/// Is it removed after `HISTORY_DEPTH` eras.
	/// If stakers hasn't been set or has been removed then empty exposure is returned.
	#[pallet::storage]
	#[pallet::getter(fn eras_stakers_clipped)]
	pub type ErasStakersClipped<T: Config> = StorageDoubleMap<
		_,
		Twox64Concat, EraIndex,
		Twox64Concat, T::AccountId,
		Exposure<T::AccountId, BalanceOf<T>>,
		ValueQuery,
	>;

	/// Similar to `ErasStakers`, this holds the preferences of validators.
	///
	/// This is keyed first by the era index to allow bulk deletion and then the stash account.
	///
	/// Is it removed after `HISTORY_DEPTH` eras.
	// If prefs hasn't been set or has been removed then 0 commission is returned.
	#[pallet::storage]
	#[pallet::getter(fn eras_validator_prefs)]
	pub type ErasValidatorPrefs<T: Config> = StorageDoubleMap<
		_,
		Twox64Concat, EraIndex,
		Twox64Concat, T::AccountId,
		ValidatorPrefs,
		ValueQuery,
	>;

	/// The total validator era payout for the last `HISTORY_DEPTH` eras.
	///
	/// Eras that haven't finished yet or has been removed doesn't have reward.
	#[pallet::storage]
	#[pallet::getter(fn eras_validator_reward)]
	pub type ErasValidatorReward<T: Config> = StorageMap<_, Twox64Concat, EraIndex, BalanceOf<T>>;

	/// Rewards for the last `HISTORY_DEPTH` eras.
	/// If reward hasn't been set or has been removed then 0 reward is returned.
	#[pallet::storage]
	#[pallet::getter(fn eras_reward_points)]
	pub type ErasRewardPoints<T: Config> = StorageMap<
		_,
		Twox64Concat, EraIndex,
		EraRewardPoints<T::AccountId>,
		ValueQuery,
	>;

	/// The total amount staked for the last `HISTORY_DEPTH` eras.
	/// If total hasn't been set or has been removed then 0 stake is returned.
	#[pallet::storage]
	#[pallet::getter(fn eras_total_stake)]
	pub type ErasTotalStake<T: Config> = StorageMap<_, Twox64Concat, EraIndex, BalanceOf<T>, ValueQuery>;

	/// Mode of era forcing.
	#[pallet::storage]
	#[pallet::getter(fn force_era)]
	pub type ForceEra<T> = StorageValue<_, Forcing, ValueQuery>;

	/// The percentage of the slash that is distributed to reporters.
	///
	/// The rest of the slashed value is handled by the `Slash`.
	#[pallet::storage]
	#[pallet::getter(fn slash_reward_fraction)]
	pub type SlashRewardFraction<T> = StorageValue<_, Perbill, ValueQuery>;

	/// The amount of currency given to reporters of a slash event which was
	/// canceled by extraordinary circumstances (e.g. governance).
	#[pallet::storage]
	#[pallet::getter(fn canceled_payout)]
	pub type CanceledSlashPayout<T: Config> = StorageValue<_, BalanceOf<T>, ValueQuery>;

	/// All unapplied slashes that are queued for later.
	#[pallet::storage]
	pub type UnappliedSlashes<T: Config> = StorageMap<
		_,
		Twox64Concat, EraIndex,
		Vec<UnappliedSlash<T::AccountId, BalanceOf<T>>>,
		ValueQuery,
	>;

	/// A mapping from still-bonded eras to the first session index of that era.
	///
	/// Must contains information for eras for the range:
	/// `[active_era - bounding_duration; active_era]`
	#[pallet::storage]
	pub(crate) type BondedEras<T: Config> = StorageValue<_, Vec<(EraIndex, SessionIndex)>, ValueQuery>;

	/// All slashing events on validators, mapped by era to the highest slash proportion
	/// and slash value of the era.
	#[pallet::storage]
	pub(crate) type ValidatorSlashInEra<T: Config> = StorageDoubleMap<
		_,
		Twox64Concat, EraIndex,
		Twox64Concat, T::AccountId,
		(Perbill, BalanceOf<T>),
	>;

	/// All slashing events on nominators, mapped by era to the highest slash value of the era.
	#[pallet::storage]
	pub(crate) type NominatorSlashInEra<T: Config> = StorageDoubleMap<
		_,
		Twox64Concat, EraIndex,
		Twox64Concat, T::AccountId,
		BalanceOf<T>,
	>;

	/// Slashing spans for stash accounts.
	#[pallet::storage]
	pub(crate) type SlashingSpans<T: Config> = StorageMap<_, Twox64Concat, T::AccountId, slashing::SlashingSpans>;

	/// Records information about the maximum slash of a stash within a slashing span,
	/// as well as how much reward has been paid out.
	#[pallet::storage]
	pub(crate) type SpanSlash<T: Config> = StorageMap<
		_,
		Twox64Concat, (T::AccountId, slashing::SpanIndex),
		slashing::SpanRecord<BalanceOf<T>>,
		ValueQuery,
	>;

	/// The earliest era for which we have a pending, unapplied slash.
	#[pallet::storage]
	pub(crate) type EarliestUnappliedSlash<T> = StorageValue<_, EraIndex>;

	/// The last planned session scheduled by the session pallet.
	///
	/// This is basically in sync with the call to [`SessionManager::new_session`].
	#[pallet::storage]
	#[pallet::getter(fn current_planned_session)]
	pub type CurrentPlannedSession<T> = StorageValue<_, SessionIndex, ValueQuery>;

	/// True if network has been upgraded to this version.
	/// Storage version of the pallet.
	///
	/// This is set to v6.0.0 for new networks.
	#[pallet::storage]
	pub(crate) type StorageVersion<T: Config> = StorageValue<_, Releases, ValueQuery>;

	#[pallet::genesis_config]
	pub struct GenesisConfig<T: Config> {
		pub history_depth: u32,
		pub validator_count: u32,
		pub minimum_validator_count: u32,
		pub invulnerables: Vec<T::AccountId>,
		pub force_era: Forcing,
		pub slash_reward_fraction: Perbill,
		pub canceled_payout: BalanceOf<T>,
		pub stakers: Vec<(T::AccountId, T::AccountId, BalanceOf<T>, StakerStatus<T::AccountId>)>,
		pub min_nominator_bond: BalanceOf<T>,
		pub min_validator_bond: BalanceOf<T>,
	}

	#[cfg(feature = "std")]
	impl<T: Config> Default for GenesisConfig<T> {
		fn default() -> Self {
			GenesisConfig {
				history_depth: 84u32,
				validator_count: Default::default(),
				minimum_validator_count: Default::default(),
				invulnerables: Default::default(),
				force_era: Default::default(),
				slash_reward_fraction: Default::default(),
				canceled_payout: Default::default(),
				stakers: Default::default(),
				min_nominator_bond: Default::default(),
				min_validator_bond: Default::default(),
			}
		}
	}

	#[pallet::genesis_build]
	impl<T: Config> GenesisBuild<T> for GenesisConfig<T> {
		fn build(&self) {
			HistoryDepth::<T>::put(self.history_depth);
			ValidatorCount::<T>::put(self.validator_count);
			MinimumValidatorCount::<T>::put(self.minimum_validator_count);
			Invulnerables::<T>::put(&self.invulnerables);
			ForceEra::<T>::put(self.force_era);
			CanceledSlashPayout::<T>::put(self.canceled_payout);
			SlashRewardFraction::<T>::put(self.slash_reward_fraction);
			StorageVersion::<T>::put(Releases::V6_0_0);
			MinNominatorBond::<T>::put(self.min_nominator_bond);
			MinValidatorBond::<T>::put(self.min_validator_bond);

			for &(ref stash, ref controller, balance, ref status) in &self.stakers {
				assert!(
					T::Currency::free_balance(&stash) >= balance,
					"Stash does not have enough balance to bond."
				);
				let _ = <Pallet<T>>::bond(
					T::Origin::from(Some(stash.clone()).into()),
					T::Lookup::unlookup(controller.clone()),
					balance,
					RewardDestination::Staked,
				);
				let _ = match status {
					StakerStatus::Validator => {
						<Pallet<T>>::validate(
							T::Origin::from(Some(controller.clone()).into()),
							Default::default(),
						)
					},
					StakerStatus::Nominator(votes) => {
						<Pallet<T>>::nominate(
							T::Origin::from(Some(controller.clone()).into()),
							votes.iter().map(|l| T::Lookup::unlookup(l.clone())).collect(),
						)
					}, _ => Ok(())
				};
			}
		}
	}

	#[pallet::event]
	#[pallet::generate_deposit(pub(super) fn deposit_event)]
	#[pallet::metadata(T::AccountId = "AccountId", BalanceOf<T> = "Balance")]
	pub enum Event<T: Config> {
		/// The era payout has been set; the first balance is the validator-payout; the second is
		/// the remainder from the maximum amount of reward.
		/// \[era_index, validator_payout, remainder\]
		EraPayout(EraIndex, BalanceOf<T>, BalanceOf<T>),
		/// The staker has been rewarded by this amount. \[stash, amount\]
		Reward(T::AccountId, BalanceOf<T>),
		/// One validator (and its nominators) has been slashed by the given amount.
		/// \[validator, amount\]
		Slash(T::AccountId, BalanceOf<T>),
		/// An old slashing report from a prior era was discarded because it could
		/// not be processed. \[session_index\]
		OldSlashingReportDiscarded(SessionIndex),
		/// A new set of stakers was elected.
		StakingElection,
		/// An account has bonded this amount. \[stash, amount\]
		///
		/// NOTE: This event is only emitted when funds are bonded via a dispatchable. Notably,
		/// it will not be emitted for staking rewards when they are added to stake.
		Bonded(T::AccountId, BalanceOf<T>),
		/// An account has unbonded this amount. \[stash, amount\]
		Unbonded(T::AccountId, BalanceOf<T>),
		/// An account has called `withdraw_unbonded` and removed unbonding chunks worth `Balance`
		/// from the unlocking queue. \[stash, amount\]
		Withdrawn(T::AccountId, BalanceOf<T>),
		/// A nominator has been kicked from a validator. \[nominator, stash\]
		Kicked(T::AccountId, T::AccountId),
		/// The election failed. No new era is planned.
		StakingElectionFailed,
	}

	#[pallet::error]
	pub enum Error<T> {
		/// Not a controller account.
		NotController,
		/// Not a stash account.
		NotStash,
		/// Stash is already bonded.
		AlreadyBonded,
		/// Controller is already paired.
		AlreadyPaired,
		/// Targets cannot be empty.
		EmptyTargets,
		/// Duplicate index.
		DuplicateIndex,
		/// Slash record index out of bounds.
		InvalidSlashIndex,
		/// Can not bond with value less than minimum required.
		InsufficientBond,
		/// Can not schedule more unlock chunks.
		NoMoreChunks,
		/// Can not rebond without unlocking chunks.
		NoUnlockChunk,
		/// Attempting to target a stash that still has funds.
		FundedTarget,
		/// Invalid era to reward.
		InvalidEraToReward,
		/// Invalid number of nominations.
		InvalidNumberOfNominations,
		/// Items are not sorted and unique.
		NotSortedAndUnique,
		/// Rewards for this era have already been claimed for this validator.
		AlreadyClaimed,
		/// Incorrect previous history depth input provided.
		IncorrectHistoryDepth,
		/// Incorrect number of slashing spans provided.
		IncorrectSlashingSpans,
		/// Internal state has become somehow corrupted and the operation cannot continue.
		BadState,
		/// Too many nomination targets supplied.
		TooManyTargets,
		/// A nomination target was supplied that was blocked or otherwise not a validator.
		BadTarget,
		/// The user has enough bond and thus cannot be chilled forcefully by an external person.
		CannotChillOther,
		/// There are too many nominators in the system. Governance needs to adjust the staking settings
		/// to keep things safe for the runtime.
		TooManyNominators,
		/// There are too many validators in the system. Governance needs to adjust the staking settings
		/// to keep things safe for the runtime.
		TooManyValidators,
	}

	#[pallet::hooks]
	impl<T: Config> Hooks<BlockNumberFor<T>> for Pallet<T> {
		fn on_runtime_upgrade() -> Weight {
			if StorageVersion::<T>::get() == Releases::V6_0_0 {
				migrations::v7::migrate::<T>()
			} else {
				T::DbWeight::get().reads(1)
			}
		}

		#[cfg(feature = "try-runtime")]
		fn pre_upgrade() -> Result<(), &'static str> {
			if StorageVersion::<T>::get() == Releases::V6_0_0 {
				migrations::v7::pre_migrate::<T>()
			} else {
				Ok(())
			}
		}

		fn on_initialize(_now: BlockNumberFor<T>) -> Weight {
			// just return the weight of the on_finalize.
			T::DbWeight::get().reads(1)
		}

		fn on_finalize(_n: BlockNumberFor<T>) {
			// Set the start of the first era.
			if let Some(mut active_era) = Self::active_era() {
				if active_era.start.is_none() {
					let now_as_millis_u64 = T::UnixTime::now().as_millis().saturated_into::<u64>();
					active_era.start = Some(now_as_millis_u64);
					// This write only ever happens once, we don't include it in the weight in general
					ActiveEra::<T>::put(active_era);
				}
			}
			// `on_finalize` weight is tracked in `on_initialize`
		}

		fn integrity_test() {
			sp_std::if_std! {
				sp_io::TestExternalities::new_empty().execute_with(||
					assert!(
						T::SlashDeferDuration::get() < T::BondingDuration::get() || T::BondingDuration::get() == 0,
						"As per documentation, slash defer duration ({}) should be less than bonding duration ({}).",
						T::SlashDeferDuration::get(),
						T::BondingDuration::get(),
					)
				);
			}
		}
	}

	#[pallet::call]
	impl<T: Config> Pallet<T> {
		/// Take the origin account as a stash and lock up `value` of its balance. `controller` will
		/// be the account that controls it.
		///
		/// `value` must be more than the `minimum_balance` specified by `T::Currency`.
		///
		/// The dispatch origin for this call must be _Signed_ by the stash account.
		///
		/// Emits `Bonded`.
		///
		/// # <weight>
		/// - Independent of the arguments. Moderate complexity.
		/// - O(1).
		/// - Three extra DB entries.
		///
		/// NOTE: Two of the storage writes (`Self::bonded`, `Self::payee`) are _never_ cleaned
		/// unless the `origin` falls below _existential deposit_ and gets removed as dust.
		/// ------------------
		/// Weight: O(1)
		/// DB Weight:
		/// - Read: Bonded, Ledger, [Origin Account], Current Era, History Depth, Locks
		/// - Write: Bonded, Payee, [Origin Account], Locks, Ledger
		/// # </weight>
		#[pallet::weight(T::WeightInfo::bond())]
		pub fn bond(
			origin: OriginFor<T>,
			controller: <T::Lookup as StaticLookup>::Source,
			#[pallet::compact] value: BalanceOf<T>,
			payee: RewardDestination<T::AccountId>,
		) -> DispatchResult {
			let stash = ensure_signed(origin)?;

			if <Bonded<T>>::contains_key(&stash) {
				Err(Error::<T>::AlreadyBonded)?
			}

			let controller = T::Lookup::lookup(controller)?;

			if <Ledger<T>>::contains_key(&controller) {
				Err(Error::<T>::AlreadyPaired)?
			}

			// Reject a bond which is considered to be _dust_.
			if value < T::Currency::minimum_balance() {
				Err(Error::<T>::InsufficientBond)?
			}

			frame_system::Pallet::<T>::inc_consumers(&stash).map_err(|_| Error::<T>::BadState)?;

			// You're auto-bonded forever, here. We might improve this by only bonding when
			// you actually validate/nominate and remove once you unbond __everything__.
			<Bonded<T>>::insert(&stash, &controller);
			<Payee<T>>::insert(&stash, payee);

			let current_era = CurrentEra::<T>::get().unwrap_or(0);
			let history_depth = Self::history_depth();
			let last_reward_era = current_era.saturating_sub(history_depth);

			let stash_balance = T::Currency::free_balance(&stash);
			let value = value.min(stash_balance);
			Self::deposit_event(Event::<T>::Bonded(stash.clone(), value));
			let item = StakingLedger {
				stash,
				total: value,
				active: value,
				unlocking: vec![],
				claimed_rewards: (last_reward_era..current_era).collect(),
			};
			Self::update_ledger(&controller, &item);
			Ok(())
		}

		/// Add some extra amount that have appeared in the stash `free_balance` into the balance up
		/// for staking.
		///
		/// Use this if there are additional funds in your stash account that you wish to bond.
		/// Unlike [`bond`] or [`unbond`] this function does not impose any limitation on the amount
		/// that can be added.
		///
		/// The dispatch origin for this call must be _Signed_ by the stash, not the controller and
		/// it can be only called when [`EraElectionStatus`] is `Closed`.
		///
		/// Emits `Bonded`.
		///
		/// # <weight>
		/// - Independent of the arguments. Insignificant complexity.
		/// - O(1).
		/// - One DB entry.
		/// ------------
		/// DB Weight:
		/// - Read: Era Election Status, Bonded, Ledger, [Origin Account], Locks
		/// - Write: [Origin Account], Locks, Ledger
		/// # </weight>
		#[pallet::weight(T::WeightInfo::bond_extra())]
		pub fn bond_extra(
			origin: OriginFor<T>,
			#[pallet::compact] max_additional: BalanceOf<T>,
		) -> DispatchResult {
			let stash = ensure_signed(origin)?;

			let controller = Self::bonded(&stash).ok_or(Error::<T>::NotStash)?;
			let mut ledger = Self::ledger(&controller).ok_or(Error::<T>::NotController)?;

			let stash_balance = T::Currency::free_balance(&stash);
			if let Some(extra) = stash_balance.checked_sub(&ledger.total) {
				let extra = extra.min(max_additional);
				ledger.total += extra;
				ledger.active += extra;
				// Last check: the new active amount of ledger must be more than ED.
				ensure!(ledger.active >= T::Currency::minimum_balance(), Error::<T>::InsufficientBond);

				Self::deposit_event(Event::<T>::Bonded(stash, extra));
				Self::update_ledger(&controller, &ledger);
			}
			Ok(())
		}

		/// Schedule a portion of the stash to be unlocked ready for transfer out after the bond
		/// period ends. If this leaves an amount actively bonded less than
		/// T::Currency::minimum_balance(), then it is increased to the full amount.
		///
		/// Once the unlock period is done, you can call `withdraw_unbonded` to actually move
		/// the funds out of management ready for transfer.
		///
		/// No more than a limited number of unlocking chunks (see `MAX_UNLOCKING_CHUNKS`)
		/// can co-exists at the same time. In that case, [`Call::withdraw_unbonded`] need
		/// to be called first to remove some of the chunks (if possible).
		///
		/// If a user encounters the `InsufficientBond` error when calling this extrinsic,
		/// they should call `chill` first in order to free up their bonded funds.
		///
		/// The dispatch origin for this call must be _Signed_ by the controller, not the stash.
		/// And, it can be only called when [`EraElectionStatus`] is `Closed`.
		///
		/// Emits `Unbonded`.
		///
		/// See also [`Call::withdraw_unbonded`].
		///
		/// # <weight>
		/// - Independent of the arguments. Limited but potentially exploitable complexity.
		/// - Contains a limited number of reads.
		/// - Each call (requires the remainder of the bonded balance to be above `minimum_balance`)
		///   will cause a new entry to be inserted into a vector (`Ledger.unlocking`) kept in storage.
		///   The only way to clean the aforementioned storage item is also user-controlled via
		///   `withdraw_unbonded`.
		/// - One DB entry.
		/// ----------
		/// Weight: O(1)
		/// DB Weight:
		/// - Read: EraElectionStatus, Ledger, CurrentEra, Locks, BalanceOf Stash,
		/// - Write: Locks, Ledger, BalanceOf Stash,
		/// </weight>
		#[pallet::weight(T::WeightInfo::unbond())]
		pub fn unbond(origin: OriginFor<T>, #[pallet::compact] value: BalanceOf<T>) -> DispatchResult {
			let controller = ensure_signed(origin)?;
			let mut ledger = Self::ledger(&controller).ok_or(Error::<T>::NotController)?;
			ensure!(
				ledger.unlocking.len() < MAX_UNLOCKING_CHUNKS,
				Error::<T>::NoMoreChunks,
			);

			let mut value = value.min(ledger.active);

			if !value.is_zero() {
				ledger.active -= value;

				// Avoid there being a dust balance left in the staking system.
				if ledger.active < T::Currency::minimum_balance() {
					value += ledger.active;
					ledger.active = Zero::zero();
				}

				let min_active_bond = if Nominators::<T>::contains_key(&ledger.stash) {
					MinNominatorBond::<T>::get()
				} else if Validators::<T>::contains_key(&ledger.stash) {
					MinValidatorBond::<T>::get()
				} else {
					Zero::zero()
				};

				// Make sure that the user maintains enough active bond for their role.
				// If a user runs into this error, they should chill first.
				ensure!(ledger.active >= min_active_bond, Error::<T>::InsufficientBond);

				// Note: in case there is no current era it is fine to bond one era more.
				let era = Self::current_era().unwrap_or(0) + T::BondingDuration::get();
				ledger.unlocking.push(UnlockChunk { value, era });
				Self::update_ledger(&controller, &ledger);
				Self::deposit_event(Event::<T>::Unbonded(ledger.stash, value));
			}
			Ok(())
		}

		/// Remove any unlocked chunks from the `unlocking` queue from our management.
		///
		/// This essentially frees up that balance to be used by the stash account to do
		/// whatever it wants.
		///
		/// The dispatch origin for this call must be _Signed_ by the controller, not the stash.
		/// And, it can be only called when [`EraElectionStatus`] is `Closed`.
		///
		/// Emits `Withdrawn`.
		///
		/// See also [`Call::unbond`].
		///
		/// # <weight>
		/// - Could be dependent on the `origin` argument and how much `unlocking` chunks exist.
		///  It implies `consolidate_unlocked` which loops over `Ledger.unlocking`, which is
		///  indirectly user-controlled. See [`unbond`] for more detail.
		/// - Contains a limited number of reads, yet the size of which could be large based on `ledger`.
		/// - Writes are limited to the `origin` account key.
		/// ---------------
		/// Complexity O(S) where S is the number of slashing spans to remove
		/// Update:
		/// - Reads: EraElectionStatus, Ledger, Current Era, Locks, [Origin Account]
		/// - Writes: [Origin Account], Locks, Ledger
		/// Kill:
		/// - Reads: EraElectionStatus, Ledger, Current Era, Bonded, Slashing Spans, [Origin
		///   Account], Locks, BalanceOf stash
		/// - Writes: Bonded, Slashing Spans (if S > 0), Ledger, Payee, Validators, Nominators,
		///   [Origin Account], Locks, BalanceOf stash.
		/// - Writes Each: SpanSlash * S
		/// NOTE: Weight annotation is the kill scenario, we refund otherwise.
		/// # </weight>
		#[pallet::weight(T::WeightInfo::withdraw_unbonded_kill(*num_slashing_spans))]
		pub fn withdraw_unbonded(
			origin: OriginFor<T>,
			num_slashing_spans: u32,
		) -> DispatchResultWithPostInfo {
			let controller = ensure_signed(origin)?;
			let mut ledger = Self::ledger(&controller).ok_or(Error::<T>::NotController)?;
			let (stash, old_total) = (ledger.stash.clone(), ledger.total);
			if let Some(current_era) = Self::current_era() {
				ledger = ledger.consolidate_unlocked(current_era)
			}

			let post_info_weight = if ledger.unlocking.is_empty() && ledger.active < T::Currency::minimum_balance() {
				// This account must have called `unbond()` with some value that caused the active
				// portion to fall below existential deposit + will have no more unlocking chunks
				// left. We can now safely remove all staking-related information.
				Self::kill_stash(&stash, num_slashing_spans)?;
				// Remove the lock.
				T::Currency::remove_lock(STAKING_ID, &stash);
				// This is worst case scenario, so we use the full weight and return None
				None
			} else {
				// This was the consequence of a partial unbond. just update the ledger and move on.
				Self::update_ledger(&controller, &ledger);

				// This is only an update, so we use less overall weight.
				Some(T::WeightInfo::withdraw_unbonded_update(num_slashing_spans))
			};

			// `old_total` should never be less than the new total because
			// `consolidate_unlocked` strictly subtracts balance.
			if ledger.total < old_total {
				// Already checked that this won't overflow by entry condition.
				let value = old_total - ledger.total;
				Self::deposit_event(Event::<T>::Withdrawn(stash, value));
			}

			Ok(post_info_weight.into())
		}

		/// Declare the desire to validate for the origin controller.
		///
		/// Effects will be felt at the beginning of the next era.
		///
		/// The dispatch origin for this call must be _Signed_ by the controller, not the stash.
		/// And, it can be only called when [`EraElectionStatus`] is `Closed`.
		///
		/// # <weight>
		/// - Independent of the arguments. Insignificant complexity.
		/// - Contains a limited number of reads.
		/// - Writes are limited to the `origin` account key.
		/// -----------
		/// Weight: O(1)
		/// DB Weight:
		/// - Read: Era Election Status, Ledger
		/// - Write: Nominators, Validators
		/// # </weight>
		#[pallet::weight(T::WeightInfo::validate())]
		pub fn validate(origin: OriginFor<T>, prefs: ValidatorPrefs) -> DispatchResult {
			let controller = ensure_signed(origin)?;

			// If this error is reached, we need to adjust the `MinValidatorBond` and start calling `chill_other`.
			// Until then, we explicitly block new validators to protect the runtime.
			if let Some(max_validators) = MaxValidatorsCount::<T>::get() {
				ensure!(CounterForValidators::<T>::get() < max_validators, Error::<T>::TooManyValidators);
			}

			let ledger = Self::ledger(&controller).ok_or(Error::<T>::NotController)?;
			ensure!(ledger.active >= MinValidatorBond::<T>::get(), Error::<T>::InsufficientBond);

			let stash = &ledger.stash;
			Self::do_remove_nominator(stash);
			Self::do_add_validator(stash, prefs);
			Ok(())
		}

		/// Declare the desire to nominate `targets` for the origin controller.
		///
		/// Effects will be felt at the beginning of the next era. This can only be called when
		/// [`EraElectionStatus`] is `Closed`.
		///
		/// The dispatch origin for this call must be _Signed_ by the controller, not the stash.
		/// And, it can be only called when [`EraElectionStatus`] is `Closed`.
		///
		/// # <weight>
		/// - The transaction's complexity is proportional to the size of `targets` (N)
		/// which is capped at CompactAssignments::LIMIT (MAX_NOMINATIONS).
		/// - Both the reads and writes follow a similar pattern.
		/// ---------
		/// Weight: O(N)
		/// where N is the number of targets
		/// DB Weight:
		/// - Reads: Era Election Status, Ledger, Current Era
		/// - Writes: Validators, Nominators
		/// # </weight>
		#[pallet::weight(T::WeightInfo::nominate(targets.len() as u32))]
		pub fn nominate(
			origin: OriginFor<T>,
			targets: Vec<<T::Lookup as StaticLookup>::Source>,
		) -> DispatchResult {
			let controller = ensure_signed(origin)?;

			// If this error is reached, we need to adjust the `MinNominatorBond` and start calling `chill_other`.
			// Until then, we explicitly block new nominators to protect the runtime.
			if let Some(max_nominators) = MaxNominatorsCount::<T>::get() {
				ensure!(CounterForNominators::<T>::get() < max_nominators, Error::<T>::TooManyNominators);
			}

			let ledger = Self::ledger(&controller).ok_or(Error::<T>::NotController)?;
			ensure!(ledger.active >= MinNominatorBond::<T>::get(), Error::<T>::InsufficientBond);

			let stash = &ledger.stash;
			ensure!(!targets.is_empty(), Error::<T>::EmptyTargets);
			ensure!(targets.len() <= T::MAX_NOMINATIONS as usize, Error::<T>::TooManyTargets);

			let old = Nominators::<T>::get(stash).map_or_else(Vec::new, |x| x.targets);

			let targets = targets.into_iter()
				.map(|t| T::Lookup::lookup(t).map_err(DispatchError::from))
				.map(|n| n.and_then(|n| if old.contains(&n) || !Validators::<T>::get(&n).blocked {
					Ok(n)
				} else {
					Err(Error::<T>::BadTarget.into())
				}))
				.collect::<result::Result<Vec<T::AccountId>, _>>()?;

			let nominations = Nominations {
				targets,
				// Initial nominations are considered submitted at era 0. See `Nominations` doc
				submitted_in: Self::current_era().unwrap_or(0),
				suppressed: false,
			};

			Self::do_remove_validator(stash);
			Self::do_add_nominator(stash, nominations);
			Ok(())
		}

		/// Declare no desire to either validate or nominate.
		///
		/// Effects will be felt at the beginning of the next era.
		///
		/// The dispatch origin for this call must be _Signed_ by the controller, not the stash.
		/// And, it can be only called when [`EraElectionStatus`] is `Closed`.
		///
		/// # <weight>
		/// - Independent of the arguments. Insignificant complexity.
		/// - Contains one read.
		/// - Writes are limited to the `origin` account key.
		/// --------
		/// Weight: O(1)
		/// DB Weight:
		/// - Read: EraElectionStatus, Ledger
		/// - Write: Validators, Nominators
		/// # </weight>
		#[pallet::weight(T::WeightInfo::chill())]
		pub fn chill(origin: OriginFor<T>) -> DispatchResult {
			let controller = ensure_signed(origin)?;
			let ledger = Self::ledger(&controller).ok_or(Error::<T>::NotController)?;
			Self::chill_stash(&ledger.stash);
			Ok(())
		}

		/// (Re-)set the payment target for a controller.
		///
		/// Effects will be felt at the beginning of the next era.
		///
		/// The dispatch origin for this call must be _Signed_ by the controller, not the stash.
		///
		/// # <weight>
		/// - Independent of the arguments. Insignificant complexity.
		/// - Contains a limited number of reads.
		/// - Writes are limited to the `origin` account key.
		/// ---------
		/// - Weight: O(1)
		/// - DB Weight:
		///     - Read: Ledger
		///     - Write: Payee
		/// # </weight>
		#[pallet::weight(T::WeightInfo::set_payee())]
		pub fn set_payee(
			origin: OriginFor<T>,
			payee: RewardDestination<T::AccountId>,
		) -> DispatchResult {
			let controller = ensure_signed(origin)?;
			let ledger = Self::ledger(&controller).ok_or(Error::<T>::NotController)?;
			let stash = &ledger.stash;
			<Payee<T>>::insert(stash, payee);
			Ok(())
		}

		/// (Re-)set the controller of a stash.
		///
		/// Effects will be felt at the beginning of the next era.
		///
		/// The dispatch origin for this call must be _Signed_ by the stash, not the controller.
		///
		/// # <weight>
		/// - Independent of the arguments. Insignificant complexity.
		/// - Contains a limited number of reads.
		/// - Writes are limited to the `origin` account key.
		/// ----------
		/// Weight: O(1)
		/// DB Weight:
		/// - Read: Bonded, Ledger New Controller, Ledger Old Controller
		/// - Write: Bonded, Ledger New Controller, Ledger Old Controller
		/// # </weight>
		#[pallet::weight(T::WeightInfo::set_controller())]
		pub fn set_controller(
			origin: OriginFor<T>,
			controller: <T::Lookup as StaticLookup>::Source,
		) -> DispatchResult {
			let stash = ensure_signed(origin)?;
			let old_controller = Self::bonded(&stash).ok_or(Error::<T>::NotStash)?;
			let controller = T::Lookup::lookup(controller)?;
			if <Ledger<T>>::contains_key(&controller) {
				Err(Error::<T>::AlreadyPaired)?
			}
			if controller != old_controller {
				<Bonded<T>>::insert(&stash, &controller);
				if let Some(l) = <Ledger<T>>::take(&old_controller) {
					<Ledger<T>>::insert(&controller, l);
				}
			}
			Ok(())
		}

		/// Sets the ideal number of validators.
		///
		/// The dispatch origin must be Root.
		///
		/// # <weight>
		/// Weight: O(1)
		/// Write: Validator Count
		/// # </weight>
		#[pallet::weight(T::WeightInfo::set_validator_count())]
		pub fn set_validator_count(
			origin: OriginFor<T>,
			#[pallet::compact] new: u32,
		) -> DispatchResult {
			ensure_root(origin)?;
			ValidatorCount::<T>::put(new);
			Ok(())
		}

		/// Increments the ideal number of validators.
		///
		/// The dispatch origin must be Root.
		///
		/// # <weight>
		/// Same as [`set_validator_count`].
		/// # </weight>
		#[pallet::weight(T::WeightInfo::set_validator_count())]
		pub fn increase_validator_count(
			origin: OriginFor<T>,
			#[pallet::compact] additional: u32,
		) -> DispatchResult {
			ensure_root(origin)?;
			ValidatorCount::<T>::mutate(|n| *n += additional);
			Ok(())
		}

		/// Scale up the ideal number of validators by a factor.
		///
		/// The dispatch origin must be Root.
		///
		/// # <weight>
		/// Same as [`set_validator_count`].
		/// # </weight>
		#[pallet::weight(T::WeightInfo::set_validator_count())]
		pub fn scale_validator_count(origin: OriginFor<T>, factor: Percent) -> DispatchResult {
			ensure_root(origin)?;
			ValidatorCount::<T>::mutate(|n| *n += factor * *n);
			Ok(())
		}

		/// Force there to be no new eras indefinitely.
		///
		/// The dispatch origin must be Root.
		///
		/// # Warning
		///
		/// The election process starts multiple blocks before the end of the era.
		/// Thus the election process may be ongoing when this is called. In this case the
		/// election will continue until the next era is triggered.
		///
		/// # <weight>
		/// - No arguments.
		/// - Weight: O(1)
		/// - Write: ForceEra
		/// # </weight>
		#[pallet::weight(T::WeightInfo::force_no_eras())]
		pub fn force_no_eras(origin: OriginFor<T>) -> DispatchResult {
			ensure_root(origin)?;
			ForceEra::<T>::put(Forcing::ForceNone);
			Ok(())
		}

		/// Force there to be a new era at the end of the next session. After this, it will be
		/// reset to normal (non-forced) behaviour.
		///
		/// The dispatch origin must be Root.
		///
		/// # Warning
		///
		/// The election process starts multiple blocks before the end of the era.
		/// If this is called just before a new era is triggered, the election process may not
		/// have enough blocks to get a result.
		///
		/// # <weight>
		/// - No arguments.
		/// - Weight: O(1)
		/// - Write ForceEra
		/// # </weight>
		#[pallet::weight(T::WeightInfo::force_new_era())]
		pub fn force_new_era(origin: OriginFor<T>) -> DispatchResult {
			ensure_root(origin)?;
			ForceEra::<T>::put(Forcing::ForceNew);
			Ok(())
		}

		/// Set the validators who cannot be slashed (if any).
		///
		/// The dispatch origin must be Root.
		///
		/// # <weight>
		/// - O(V)
		/// - Write: Invulnerables
		/// # </weight>
		#[pallet::weight(T::WeightInfo::set_invulnerables(invulnerables.len() as u32))]
		pub fn set_invulnerables(
			origin: OriginFor<T>,
			invulnerables: Vec<T::AccountId>,
		) -> DispatchResult {
			ensure_root(origin)?;
			<Invulnerables<T>>::put(invulnerables);
			Ok(())
		}

		/// Force a current staker to become completely unstaked, immediately.
		///
		/// The dispatch origin must be Root.
		///
		/// # <weight>
		/// O(S) where S is the number of slashing spans to be removed