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/// Writes: Bonded, Slashing Spans (if S > 0), Ledger, Payee, Validators, Nominators, Account, Locks
/// Writes Each: SpanSlash * S
/// # </weight>
#[weight = T::WeightInfo::force_unstake(*num_slashing_spans)]
fn force_unstake(origin, stash: T::AccountId, num_slashing_spans: u32) {
Self::kill_stash(&stash, num_slashing_spans)?;
// remove the lock.
T::Currency::remove_lock(STAKING_ID, &stash);
}
/// Force there to be a new era at the end of sessions indefinitely.
///
/// The dispatch origin must be Root.
///
#[weight = T::WeightInfo::force_new_era_always()]
ForceEra::put(Forcing::ForceAlways);
}
/// Cancel enactment of a deferred slash.
///
/// Can be called by the `T::SlashCancelOrigin`.
///
/// Parameters: era and indices of the slashes for that era to kill.
/// Complexity: O(U + S)
/// with U unapplied slashes weighted with U=1000
/// and S is the number of slash indices to be canceled.
/// - Read: Unapplied Slashes
/// - Write: Unapplied Slashes
#[weight = T::WeightInfo::cancel_deferred_slash(slash_indices.len() as u32)]
fn cancel_deferred_slash(origin, era: EraIndex, slash_indices: Vec<u32>) {
T::SlashCancelOrigin::ensure_origin(origin)?;
ensure!(!slash_indices.is_empty(), Error::<T>::EmptyTargets);
ensure!(is_sorted_and_unique(&slash_indices), Error::<T>::NotSortedAndUnique);
let mut unapplied = <Self as Store>::UnappliedSlashes::get(&era);
let last_item = slash_indices[slash_indices.len() - 1];
ensure!((last_item as usize) < unapplied.len(), Error::<T>::InvalidSlashIndex);
for (removed, index) in slash_indices.into_iter().enumerate() {
let index = (index as usize) - removed;
unapplied.remove(index);
}
<Self as Store>::UnappliedSlashes::insert(&era, &unapplied);
}
/// Pay out all the stakers behind a single validator for a single era.
///
/// - `validator_stash` is the stash account of the validator. Their nominators, up to
/// `T::MaxNominatorRewardedPerValidator`, will also receive their rewards.
/// - `era` may be any era between `[current_era - history_depth; current_era]`.
///
/// The origin of this call must be _Signed_. Any account can call this function, even if
/// it is not one of the stakers.
///
/// This can only be called when [`EraElectionStatus`] is `Closed`.
///
/// # <weight>
/// - Time complexity: at most O(MaxNominatorRewardedPerValidator).
/// - Contains a limited number of reads and writes.
/// -----------
/// N is the Number of payouts for the validator (including the validator)
/// Weight:
/// - Reward Destination Staked: O(N)
/// - Reward Destination Controller (Creating): O(N)
/// - Read: EraElectionStatus, CurrentEra, HistoryDepth, ErasValidatorReward,
/// ErasStakersClipped, ErasRewardPoints, ErasValidatorPrefs (8 items)
/// - Read Each: Bonded, Ledger, Payee, Locks, System Account (5 items)
/// - Write Each: System Account, Locks, Ledger (3 items)
///
/// NOTE: weights are assuming that payouts are made to alive stash account (Staked).
/// Paying even a dead controller is cheaper weight-wise. We don't do any refunds here.
#[weight = T::WeightInfo::payout_stakers_alive_staked(T::MaxNominatorRewardedPerValidator::get())]
fn payout_stakers(origin, validator_stash: T::AccountId, era: EraIndex) -> DispatchResult {
ensure!(Self::era_election_status().is_closed(), Error::<T>::CallNotAllowed);
ensure_signed(origin)?;
Self::do_payout_stakers(validator_stash, era)
}
/// Rebond a portion of the stash scheduled to be unlocked.
///
/// The dispatch origin must be signed by the controller, and it can be only called when
/// [`EraElectionStatus`] is `Closed`.
///
/// - Time complexity: O(L), where L is unlocking chunks
/// - Bounded by `MAX_UNLOCKING_CHUNKS`.
/// - Storage changes: Can't increase storage, only decrease it.
/// ---------------
/// - DB Weight:
/// - Reads: EraElectionStatus, Ledger, Locks, [Origin Account]
/// - Writes: [Origin Account], Locks, Ledger
#[weight = T::WeightInfo::rebond(MAX_UNLOCKING_CHUNKS as u32)]
fn rebond(origin, #[compact] value: BalanceOf<T>) -> DispatchResultWithPostInfo {
ensure!(Self::era_election_status().is_closed(), Error::<T>::CallNotAllowed);
let controller = ensure_signed(origin)?;
let ledger = Self::ledger(&controller).ok_or(Error::<T>::NotController)?;
ensure!(!ledger.unlocking.is_empty(), Error::<T>::NoUnlockChunk);
// last check: the new active amount of ledger must be more than ED.
ensure!(ledger.active >= T::Currency::minimum_balance(), Error::<T>::InsufficientValue);
Ok(Some(
35 * WEIGHT_PER_MICROS
+ 50 * WEIGHT_PER_NANOS * (ledger.unlocking.len() as Weight)
+ T::DbWeight::get().reads_writes(3, 2)
).into())
/// Set `HistoryDepth` value. This function will delete any history information
/// when `HistoryDepth` is reduced.
///
/// Parameters:
/// - `new_history_depth`: The new history depth you would like to set.
/// - `era_items_deleted`: The number of items that will be deleted by this dispatch.
/// This should report all the storage items that will be deleted by clearing old
/// era history. Needed to report an accurate weight for the dispatch. Trusted by
/// `Root` to report an accurate number.
///
/// # <weight>
/// - E: Number of history depths removed, i.e. 10 -> 7 = 3
/// - DB Weight:
/// - Reads: Current Era, History Depth
/// - Writes: History Depth
/// - Clear Prefix Each: Era Stakers, EraStakersClipped, ErasValidatorPrefs
/// - Writes Each: ErasValidatorReward, ErasRewardPoints, ErasTotalStake, ErasStartSessionIndex
/// # </weight>
#[weight = T::WeightInfo::set_history_depth(*_era_items_deleted)]
fn set_history_depth(origin,
#[compact] new_history_depth: EraIndex,
#[compact] _era_items_deleted: u32,
) {
ensure_root(origin)?;
if let Some(current_era) = Self::current_era() {
HistoryDepth::mutate(|history_depth| {
let last_kept = current_era.checked_sub(*history_depth).unwrap_or(0);
let new_last_kept = current_era.checked_sub(new_history_depth).unwrap_or(0);
for era_index in last_kept..new_last_kept {
Self::clear_era_information(era_index);
}
*history_depth = new_history_depth
})
}
}
/// Remove all data structure concerning a staker/stash once its balance is at the minimum.
/// This is essentially equivalent to `withdraw_unbonded` except it can be called by anyone
/// and the target `stash` must have no funds left beyond the ED.
///
/// This can be called from any origin.
///
/// - `stash`: The stash account to reap. Its balance must be zero.
///
/// # <weight>
/// Complexity: O(S) where S is the number of slashing spans on the account.
/// DB Weight:
/// - Reads: Stash Account, Bonded, Slashing Spans, Locks
/// - Writes: Bonded, Slashing Spans (if S > 0), Ledger, Payee, Validators, Nominators, Stash Account, Locks
/// - Writes Each: SpanSlash * S
/// # </weight>
#[weight = T::WeightInfo::reap_stash(*num_slashing_spans)]
fn reap_stash(_origin, stash: T::AccountId, num_slashing_spans: u32) {
let at_minimum = T::Currency::total_balance(&stash) == T::Currency::minimum_balance();
ensure!(at_minimum, Error::<T>::FundedTarget);
Self::kill_stash(&stash, num_slashing_spans)?;
/// Submit an election result to the chain. If the solution:
///
/// 1. is valid.
/// 2. has a better score than a potentially existing solution on chain.
///
/// then, it will be _put_ on chain.
///
/// A solution consists of two pieces of data:
///
/// 1. `winners`: a flat vector of all the winners of the round.
/// 2. `assignments`: the compact version of an assignment vector that encodes the edge
/// weights.
///
/// Both of which may be computed using _phragmen_, or any other algorithm.
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///
/// Additionally, the submitter must provide:
///
/// - The `score` that they claim their solution has.
///
/// Both validators and nominators will be represented by indices in the solution. The
/// indices should respect the corresponding types ([`ValidatorIndex`] and
/// [`NominatorIndex`]). Moreover, they should be valid when used to index into
/// [`SnapshotValidators`] and [`SnapshotNominators`]. Any invalid index will cause the
/// solution to be rejected. These two storage items are set during the election window and
/// may be used to determine the indices.
///
/// A solution is valid if:
///
/// 0. It is submitted when [`EraElectionStatus`] is `Open`.
/// 1. Its claimed score is equal to the score computed on-chain.
/// 2. Presents the correct number of winners.
/// 3. All indexes must be value according to the snapshot vectors. All edge values must
/// also be correct and should not overflow the granularity of the ratio type (i.e. 256
/// or billion).
/// 4. For each edge, all targets are actually nominated by the voter.
/// 5. Has correct self-votes.
///
/// A solutions score is consisted of 3 parameters:
///
/// 1. `min { support.total }` for each support of a winner. This value should be maximized.
/// 2. `sum { support.total }` for each support of a winner. This value should be minimized.
/// 3. `sum { support.total^2 }` for each support of a winner. This value should be
/// minimized (to ensure less variance)
///
/// # <weight>
/// The transaction is assumed to be the longest path, a better solution.
/// - Initial solution is almost the same.
/// - Worse solution is retraced in pre-dispatch-checks which sets its own weight.
#[weight = T::WeightInfo::submit_solution_better(
size.validators.into(),
size.nominators.into(),
compact.voter_count() as u32,
winners.len() as u32,
)]
pub fn submit_election_solution(
origin,
winners: Vec<ValidatorIndex>,
compact: CompactAssignments,
size: ElectionSize,
) -> DispatchResultWithPostInfo {
let _who = ensure_signed(origin)?;
Self::check_and_replace_solution(
winners,
ElectionCompute::Signed,
score,
era,
}
/// Unsigned version of `submit_election_solution`.
///
/// Note that this must pass the [`ValidateUnsigned`] check which only allows transactions
/// from the local node to be included. In other words, only the block author can include a
/// transaction in the block.
///
/// # <weight>
/// See [`submit_election_solution`].
#[weight = T::WeightInfo::submit_solution_better(
size.validators.into(),
size.nominators.into(),
compact.voter_count() as u32,
winners.len() as u32,
)]
pub fn submit_election_solution_unsigned(
origin,
winners: Vec<ValidatorIndex>,
compact: CompactAssignments,
size: ElectionSize,
) -> DispatchResultWithPostInfo {
let adjustments = Self::check_and_replace_solution(
ElectionCompute::Unsigned,
score,
era,
).expect(
"An unsigned solution can only be submitted by validators; A validator should \
always produce correct solutions, else this block should not be imported, thus \
effectively depriving the validators from their authoring reward. Hence, this panic
is expected."
);
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/// Remove the given nominations from the calling validator.
///
/// 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`. The controller
/// account should represent a validator.
///
/// - `who`: A list of nominator stash accounts who are nominating this validator which
/// should no longer be nominating this validator.
///
/// Note: Making this call only makes sense if you first set the validator preferences to
/// block any further nominations.
#[weight = T::WeightInfo::kick(who.len() as u32)]
pub fn kick(origin, who: Vec<<T::Lookup as StaticLookup>::Source>) -> DispatchResult {
let controller = ensure_signed(origin)?;
ensure!(Self::era_election_status().is_closed(), Error::<T>::CallNotAllowed);
let ledger = Self::ledger(&controller).ok_or(Error::<T>::NotController)?;
let stash = &ledger.stash;
for nom_stash in who.into_iter()
.map(T::Lookup::lookup)
.collect::<Result<Vec<T::AccountId>, _>>()?
.into_iter()
{
Nominators::<T>::mutate(&nom_stash, |maybe_nom| if let Some(ref mut nom) = maybe_nom {
if let Some(pos) = nom.targets.iter().position(|v| v == stash) {
nom.targets.swap_remove(pos);
Self::deposit_event(RawEvent::Kicked(nom_stash.clone(), stash.clone()));
}
});
}
Ok(())
}
impl<T: Config> Module<T> {
/// The total balance that can be slashed from a stash account as of right now.
pub fn slashable_balance_of(stash: &T::AccountId) -> BalanceOf<T> {
// Weight note: consider making the stake accessible through stash.
Self::bonded(stash).and_then(Self::ledger).map(|l| l.active).unwrap_or_default()
/// Internal impl of [`Self::slashable_balance_of`] that returns [`VoteWeight`].
pub fn slashable_balance_of_vote_weight(
stash: &T::AccountId,
issuance: BalanceOf<T>,
) -> VoteWeight {
T::CurrencyToVote::to_vote(Self::slashable_balance_of(stash), issuance)
}
/// Returns a closure around `slashable_balance_of_vote_weight` that can be passed around.
///
/// This prevents call sites from repeatedly requesting `total_issuance` from backend. But it is
/// important to be only used while the total issuance is not changing.
pub fn slashable_balance_of_fn() -> Box<dyn Fn(&T::AccountId) -> VoteWeight> {
// NOTE: changing this to unboxed `impl Fn(..)` return type and the module will still
// compile, while some types in mock fail to resolve.
let issuance = T::Currency::total_issuance();
Box::new(move |who: &T::AccountId| -> VoteWeight {
Self::slashable_balance_of_vote_weight(who, issuance)
})
}
/// Dump the list of validators and nominators into vectors and keep them on-chain.
///
/// This data is used to efficiently evaluate election results. returns `true` if the operation
/// is successful.
pub fn create_stakers_snapshot() -> (bool, Weight) {
let mut consumed_weight = 0;
let mut add_db_reads_writes = |reads, writes| {
consumed_weight += T::DbWeight::get().reads_writes(reads, writes);
};
let validators = <Validators<T>>::iter().map(|(v, _)| v).collect::<Vec<_>>();
let mut nominators = <Nominators<T>>::iter().map(|(n, _)| n).collect::<Vec<_>>();
let num_validators = validators.len();
let num_nominators = nominators.len();
add_db_reads_writes((num_validators + num_nominators) as Weight, 0);
if
num_validators > MAX_VALIDATORS ||
num_nominators.saturating_add(num_validators) > MAX_NOMINATORS
{
log!(
warn,
"Snapshot size too big [{} <> {}][{} <> {}].",
num_validators,
MAX_VALIDATORS,
num_nominators,
MAX_NOMINATORS,
);
} else {
// all validators nominate themselves;
nominators.extend(validators.clone());
<SnapshotValidators<T>>::put(validators);
<SnapshotNominators<T>>::put(nominators);
add_db_reads_writes(0, 2);
(true, consumed_weight)
}
}
/// Clears both snapshots of stakers.
fn kill_stakers_snapshot() {
<SnapshotValidators<T>>::kill();
<SnapshotNominators<T>>::kill();
}
fn do_payout_stakers(validator_stash: T::AccountId, era: EraIndex) -> DispatchResult {
// Validate input data
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let current_era = CurrentEra::get().ok_or(Error::<T>::InvalidEraToReward)?;
ensure!(era <= current_era, Error::<T>::InvalidEraToReward);
let history_depth = Self::history_depth();
ensure!(era >= current_era.saturating_sub(history_depth), Error::<T>::InvalidEraToReward);
// Note: if era has no reward to be claimed, era may be future. better not to update
// `ledger.claimed_rewards` in this case.
let era_payout = <ErasValidatorReward<T>>::get(&era)
.ok_or_else(|| Error::<T>::InvalidEraToReward)?;
let controller = Self::bonded(&validator_stash).ok_or(Error::<T>::NotStash)?;
let mut ledger = <Ledger<T>>::get(&controller).ok_or_else(|| Error::<T>::NotController)?;
ledger.claimed_rewards.retain(|&x| x >= current_era.saturating_sub(history_depth));
match ledger.claimed_rewards.binary_search(&era) {
Ok(_) => Err(Error::<T>::AlreadyClaimed)?,
Err(pos) => ledger.claimed_rewards.insert(pos, era),
}
let exposure = <ErasStakersClipped<T>>::get(&era, &ledger.stash);
/* Input data seems good, no errors allowed after this point */
<Ledger<T>>::insert(&controller, &ledger);
// Get Era reward points. It has TOTAL and INDIVIDUAL
// Find the fraction of the era reward that belongs to the validator
// Take that fraction of the eras rewards to split to nominator and validator
//
// Then look at the validator, figure out the proportion of their reward
// which goes to them and each of their nominators.
let era_reward_points = <ErasRewardPoints<T>>::get(&era);
let total_reward_points = era_reward_points.total;
let validator_reward_points = era_reward_points.individual.get(&ledger.stash)
.map(|points| *points)
.unwrap_or_else(|| Zero::zero());
// Nothing to do if they have no reward points.
if validator_reward_points.is_zero() { return Ok(())}
// This is the fraction of the total reward that the validator and the
// nominators will get.
let validator_total_reward_part = Perbill::from_rational(
validator_reward_points,
total_reward_points,
);
// This is how much validator + nominators are entitled to.
let validator_total_payout = validator_total_reward_part * era_payout;
let validator_prefs = Self::eras_validator_prefs(&era, &validator_stash);
// Validator first gets a cut off the top.
let validator_commission = validator_prefs.commission;
let validator_commission_payout = validator_commission * validator_total_payout;
let validator_leftover_payout = validator_total_payout - validator_commission_payout;
// Now let's calculate how this is split to the validator.
let validator_exposure_part = Perbill::from_rational(
exposure.own,
exposure.total,
);
let validator_staking_payout = validator_exposure_part * validator_leftover_payout;
// We can now make total validator payout:
if let Some(imbalance) = Self::make_payout(
&ledger.stash,
validator_staking_payout + validator_commission_payout
) {
Self::deposit_event(RawEvent::Reward(ledger.stash, imbalance.peek()));
}
// Lets now calculate how this is split to the nominators.
// Reward only the clipped exposures. Note this is not necessarily sorted.
for nominator in exposure.others.iter() {
let nominator_exposure_part = Perbill::from_rational(
nominator.value,
exposure.total,
);
let nominator_reward: BalanceOf<T> = nominator_exposure_part * validator_leftover_payout;
// We can now make nominator payout:
if let Some(imbalance) = Self::make_payout(&nominator.who, nominator_reward) {
Self::deposit_event(RawEvent::Reward(nominator.who.clone(), imbalance.peek()));
}
}
Ok(())
}
/// Update the ledger for a controller.
///
/// This will also update the stash lock.
fn update_ledger(
controller: &T::AccountId,
ledger: &StakingLedger<T::AccountId, BalanceOf<T>>
) {
T::Currency::set_lock(
STAKING_ID,
&ledger.stash,
ledger.total,
<Ledger<T>>::insert(controller, ledger);
}
/// Chill a stash account.
fn chill_stash(stash: &T::AccountId) {
<Validators<T>>::remove(stash);
<Nominators<T>>::remove(stash);
}
/// Actually make a payment to a staker. This uses the currency's reward function
/// to pay the right payee for the given staker account.
fn make_payout(stash: &T::AccountId, amount: BalanceOf<T>) -> Option<PositiveImbalanceOf<T>> {
let dest = Self::payee(stash);
match dest {
RewardDestination::Controller => Self::bonded(stash)
.and_then(|controller|
Some(T::Currency::deposit_creating(&controller, amount))
),
RewardDestination::Stash =>
T::Currency::deposit_into_existing(stash, amount).ok(),
RewardDestination::Staked => Self::bonded(stash)
.and_then(|c| Self::ledger(&c).map(|l| (c, l)))
.and_then(|(controller, mut l)| {
l.active += amount;
l.total += amount;
let r = T::Currency::deposit_into_existing(stash, amount).ok();
Self::update_ledger(&controller, &l);
RewardDestination::Account(dest_account) => {
Some(T::Currency::deposit_creating(&dest_account, amount))
Wei Tang
committed
},
RewardDestination::None => None,
/// Plan a new session potentially trigger a new era.
fn new_session(session_index: SessionIndex) -> Option<Vec<T::AccountId>> {
if let Some(current_era) = Self::current_era() {
// Initial era has been set.
let current_era_start_session_index = Self::eras_start_session_index(current_era)
.unwrap_or_else(|| {
frame_support::print("Error: start_session_index must be set for current_era");
0
});
let era_length = session_index.checked_sub(current_era_start_session_index)
.unwrap_or(0); // Must never happen.
match ForceEra::get() {
Forcing::ForceNew => ForceEra::kill(),
Forcing::ForceAlways => (),
Forcing::NotForcing if era_length >= T::SessionsPerEra::get() => (),
// Either `ForceNone`, or `NotForcing && era_length < T::SessionsPerEra::get()`.
if era_length + 1 == T::SessionsPerEra::get() {
} else if era_length >= T::SessionsPerEra::get() {
// Should only happen when we are ready to trigger an era but we have ForceNone,
// otherwise previous arm would short circuit.
Self::close_election_window();
Self::new_era(session_index)
} else {
// Set initial era
Self::new_era(session_index)
/// Basic and cheap checks that we perform in validate unsigned, and in the execution.
///
/// State reads: ElectionState, CurrentEr, QueuedScore.
///
/// This function does weight refund in case of errors, which is based upon the fact that it is
/// called at the very beginning of the call site's function.
pub fn pre_dispatch_checks(score: ElectionScore, era: EraIndex) -> DispatchResultWithPostInfo {
// discard solutions that are not in-time
// check window open
ensure!(
Self::era_election_status().is_open(),
Error::<T>::OffchainElectionEarlySubmission.with_weight(T::DbWeight::get().reads(1)),
if let Some(current_era) = Self::current_era() {
Error::<T>::OffchainElectionEarlySubmission.with_weight(T::DbWeight::get().reads(2)),
)
}
// assume the given score is valid. Is it better than what we have on-chain, if we have any?
if let Some(queued_score) = Self::queued_score() {
ensure!(
Kian Paimani
committed
is_score_better(score, queued_score, T::MinSolutionScoreBump::get()),
Error::<T>::OffchainElectionWeakSubmission.with_weight(T::DbWeight::get().reads(3)),
}
/// Checks a given solution and if correct and improved, writes it on chain as the queued result
/// of the next round. This may be called by both a signed and an unsigned transaction.
pub fn check_and_replace_solution(
winners: Vec<ValidatorIndex>,
compact_assignments: CompactAssignments,
compute: ElectionCompute,
claimed_score: ElectionScore,
election_size: ElectionSize,
) -> DispatchResultWithPostInfo {
// Do the basic checks. era, claimed score and window open.
let _ = Self::pre_dispatch_checks(claimed_score, era)?;
// before we read any further state, we check that the unique targets in compact is same as
// compact. is a all in-memory check and easy to do. Moreover, it ensures that the solution
// is not full of bogus edges that can cause lots of reads to SlashingSpans. Thus, we can
// assume that the storage access of this function is always O(|winners|), not
// O(|compact.edge_count()|).
ensure!(
compact_assignments.unique_targets().len() == winners.len(),
Error::<T>::OffchainElectionBogusWinnerCount,
// Check that the number of presented winners is sane. Most often we have more candidates
// than we need. Then it should be `Self::validator_count()`. Else it should be all the
let snapshot_validators_length = <SnapshotValidators<T>>::decode_len()
.map(|l| l as u32)
.ok_or_else(|| Error::<T>::SnapshotUnavailable)?;
// size of the solution must be correct.
ensure!(
snapshot_validators_length == u32::from(election_size.validators),
Error::<T>::OffchainElectionBogusElectionSize,
// check the winner length only here and when we know the length of the snapshot validators
// length.
let desired_winners = Self::validator_count().min(snapshot_validators_length);
ensure!(winners.len() as u32 == desired_winners, Error::<T>::OffchainElectionBogusWinnerCount);
let snapshot_nominators_len = <SnapshotNominators<T>>::decode_len()
.map(|l| l as u32)
.ok_or_else(|| Error::<T>::SnapshotUnavailable)?;
// rest of the size of the solution must be correct.
ensure!(
snapshot_nominators_len == election_size.nominators,
Error::<T>::OffchainElectionBogusElectionSize,
// decode snapshot validators.
let snapshot_validators = Self::snapshot_validators()
.ok_or(Error::<T>::SnapshotUnavailable)?;
// check if all winners were legit; this is rather cheap. Replace with accountId.
let winners = winners.into_iter().map(|widx| {
// NOTE: at the moment, since staking is explicitly blocking any offence until election
// is closed, we don't check here if the account id at `snapshot_validators[widx]` is
// actually a validator. If this ever changes, this loop needs to also check this.
snapshot_validators.get(widx as usize).cloned().ok_or(Error::<T>::OffchainElectionBogusWinner)
}).collect::<Result<Vec<T::AccountId>, Error<T>>>()?;
// decode the rest of the snapshot.
let snapshot_nominators = Self::snapshot_nominators()
.ok_or(Error::<T>::SnapshotUnavailable)?;
// helpers
let nominator_at = |i: NominatorIndex| -> Option<T::AccountId> {
snapshot_nominators.get(i as usize).cloned()
};
let validator_at = |i: ValidatorIndex| -> Option<T::AccountId> {
snapshot_validators.get(i as usize).cloned()
};
// un-compact.
let assignments = compact_assignments.into_assignment(
nominator_at,
validator_at,
).map_err(|e| {
// log the error since it is not propagated into the runtime error.
log!(warn, "un-compacting solution failed due to {:?}", e);
Error::<T>::OffchainElectionBogusCompact
})?;
// check all nominators actually including the claimed vote. Also check correct self votes.
// Note that we assume all validators and nominators in `assignments` are properly bonded,
// because they are coming from the snapshot via a given index.
for Assignment { who, distribution } in assignments.iter() {
let is_validator = <Validators<T>>::contains_key(&who);
let maybe_nomination = Self::nominators(&who);
if !(maybe_nomination.is_some() ^ is_validator) {
// all of the indices must map to either a validator or a nominator. If this is ever
// not the case, then the locking system of staking is most likely faulty, or we
// have bigger problems.
log!(error, "detected an error in the staking locking and snapshot.");
return Err(Error::<T>::OffchainElectionBogusNominator.into());
}
if !is_validator {
// a normal vote
let nomination = maybe_nomination.expect(
"exactly one of `maybe_validator` and `maybe_nomination.is_some` is true. \
is_validator is false; maybe_nomination is some; qed"
);
// NOTE: we don't really have to check here if the sum of all edges are the
// nominator correct. Un-compacting assures this by definition.
for (t, _) in distribution {
// each target in the provided distribution must be actually nominated by the
// nominator after the last non-zero slash.
if nomination.targets.iter().find(|&tt| tt == t).is_none() {
return Err(Error::<T>::OffchainElectionBogusNomination.into());
}
if <Self as Store>::SlashingSpans::get(&t).map_or(
false,
|spans| nomination.submitted_in < spans.last_nonzero_slash(),
) {
return Err(Error::<T>::OffchainElectionSlashedNomination.into());
}
}
} else {
// a self vote
ensure!(distribution.len() == 1, Error::<T>::OffchainElectionBogusSelfVote);
ensure!(distribution[0].0 == *who, Error::<T>::OffchainElectionBogusSelfVote);
// defensive only. A compact assignment of length one does NOT encode the weight and
// it is always created to be 100%.
ensure!(
distribution[0].1 == OffchainAccuracy::one(),
Error::<T>::OffchainElectionBogusSelfVote,
);
}
}
// convert into staked assignments.
let staked_assignments = sp_npos_elections::assignment_ratio_to_staked(
);
// build the support map thereof in order to evaluate.
let supports = to_supports(&winners, &staked_assignments)
.map_err(|_| Error::<T>::OffchainElectionBogusEdge)?;
// Check if the score is the same as the claimed one.
let submitted_score = (&supports).evaluate();
ensure!(submitted_score == claimed_score, Error::<T>::OffchainElectionBogusScore);
// At last, alles Ok. Exposures and store the result.
let exposures = Self::collect_exposures(supports);
log!(
info,
"A better solution (with compute {:?} and score {:?}) has been validated and stored \
on chain.",
);
// write new results.
<QueuedElected<T>>::put(ElectionResult {
elected_stashes: winners,
exposures,
});
QueuedScore::put(submitted_score);
// emit event.
Self::deposit_event(RawEvent::SolutionStored(compute));
/// Start a session potentially starting an era.
fn start_session(start_session: SessionIndex) {
let next_active_era = Self::active_era().map(|e| e.index + 1).unwrap_or(0);
// This is only `Some` when current era has already progressed to the next era, while the
// active era is one behind (i.e. in the *last session of the active era*, or *first session
// of the new current era*, depending on how you look at it).
if let Some(next_active_era_start_session_index) =
Self::eras_start_session_index(next_active_era)
{
if next_active_era_start_session_index == start_session {
Self::start_era(start_session);
} else if next_active_era_start_session_index < start_session {
// This arm should never happen, but better handle it than to stall the staking
// pallet.
frame_support::print("Warning: A session appears to have been skipped.");
Self::start_era(start_session);
}
}
/// End a session potentially ending an era.
fn end_session(session_index: SessionIndex) {
if let Some(active_era) = Self::active_era() {
if let Some(next_active_era_start_session_index) =
{
if next_active_era_start_session_index == session_index + 1 {
Self::end_era(active_era, session_index);
}
/// * Increment `active_era.index`,
/// * reset `active_era.start`,
/// * update `BondedEras` and apply slashes.
fn start_era(start_session: SessionIndex) {
let active_era = ActiveEra::mutate(|active_era| {
let new_index = active_era.as_ref().map(|info| info.index + 1).unwrap_or(0);
*active_era = Some(ActiveEraInfo {
index: new_index,
// Set new active era start in next `on_finalize`. To guarantee usage of `Time`
start: None,
});
new_index
let bonding_duration = T::BondingDuration::get();
BondedEras::mutate(|bonded| {
if active_era > bonding_duration {
let first_kept = active_era - bonding_duration;
// prune out everything that's from before the first-kept index.
let n_to_prune = bonded.iter()
.take_while(|&&(era_idx, _)| era_idx < first_kept)
.count();
// kill slashing metadata.
for (pruned_era, _) in bonded.drain(..n_to_prune) {
slashing::clear_era_metadata::<T>(pruned_era);
}
if let Some(&(_, first_session)) = bonded.first() {
T::SessionInterface::prune_historical_up_to(first_session);
}
Self::apply_unapplied_slashes(active_era);
}
/// Compute payout for era.
fn end_era(active_era: ActiveEraInfo, _session_index: SessionIndex) {
// Note: active_era_start can be None if end era is called during genesis config.
if let Some(active_era_start) = active_era.start {
let now_as_millis_u64 = T::UnixTime::now().as_millis().saturated_into::<u64>();
let era_duration = (now_as_millis_u64 - active_era_start).saturated_into::<u64>();
let staked = Self::eras_total_stake(&active_era.index);
let issuance = T::Currency::total_issuance();
let (validator_payout, rest) = T::EraPayout::era_payout(staked, issuance, era_duration);
Self::deposit_event(RawEvent::EraPayout(active_era.index, validator_payout, rest));
<ErasValidatorReward<T>>::insert(&active_era.index, validator_payout);
T::RewardRemainder::on_unbalanced(T::Currency::issue(rest));
}
}
/// Plan a new era. Return the potential new staking set.
fn new_era(start_session_index: SessionIndex) -> Option<Vec<T::AccountId>> {
// Increment or set current era.
let current_era = CurrentEra::mutate(|s| {
*s = Some(s.map(|s| s + 1).unwrap_or(0));
s.unwrap()
});
ErasStartSessionIndex::insert(¤t_era, &start_session_index);
// Clean old era information.
if let Some(old_era) = current_era.checked_sub(Self::history_depth() + 1) {
Self::clear_era_information(old_era);
}
// Set staking information for new era.
let maybe_new_validators = Self::select_and_update_validators(current_era);
// TWO_PHASE_NOTE: use this later on.
let _unused_new_validators = Self::enact_election(current_era);
/// Remove all the storage items associated with the election.
fn close_election_window() {
// Close window.
<EraElectionStatus<T>>::put(ElectionStatus::Closed);
// Kill snapshots.
Self::kill_stakers_snapshot();
// Don't track final session.
IsCurrentSessionFinal::put(false);
}
/// Select the new validator set at the end of the era.
///
/// Runs [`try_do_phragmen`] and updates the following storage items:
/// - [`EraElectionStatus`]: with `None`.
/// - [`ErasStakers`]: with the new staker set.
/// - [`ErasStakersClipped`].
/// - [`ErasValidatorPrefs`].
/// - [`ErasTotalStake`]: with the new total stake.
/// - [`SnapshotValidators`] and [`SnapshotNominators`] are both removed.
///
/// Internally, [`QueuedElected`], snapshots and [`QueuedScore`] are also consumed.
///
/// If the election has been successful, It passes the new set upwards.
///
/// This should only be called at the end of an era.
fn select_and_update_validators(current_era: EraIndex) -> Option<Vec<T::AccountId>> {
if let Some(ElectionResult::<T::AccountId, BalanceOf<T>> {
elected_stashes,
exposures,
compute,
}) = Self::try_do_election() {
// Totally close the election round and data.
Self::close_election_window();
// Populate Stakers and write slot stake.
let mut total_stake: BalanceOf<T> = Zero::zero();
exposures.into_iter().for_each(|(stash, exposure)| {
total_stake = total_stake.saturating_add(exposure.total);
<ErasStakers<T>>::insert(current_era, &stash, &exposure);
let mut exposure_clipped = exposure;
let clipped_max_len = T::MaxNominatorRewardedPerValidator::get() as usize;
if exposure_clipped.others.len() > clipped_max_len {
exposure_clipped.others.sort_by(|a, b| a.value.cmp(&b.value).reverse());
exposure_clipped.others.truncate(clipped_max_len);
<ErasStakersClipped<T>>::insert(¤t_era, &stash, exposure_clipped);
});
// Insert current era staking information
<ErasTotalStake<T>>::insert(¤t_era, total_stake);
// collect the pref of all winners
for stash in &elected_stashes {
let pref = Self::validators(stash);
<ErasValidatorPrefs<T>>::insert(¤t_era, stash, pref);
// emit event
Self::deposit_event(RawEvent::StakingElection(compute));
if current_era > 0 {
log!(
info,
"new validator set of size {:?} has been elected via {:?} for staring era {:?}",
elected_stashes.len(),
compute,
current_era,
);
}
Some(elected_stashes)
} else {
None
}
}
/// Select a new validator set from the assembled stakers and their role preferences. It tries
/// first to peek into [`QueuedElected`]. Otherwise, it runs a new on-chain phragmen election.