[NPoS] Implements dynamic number of nominators (#12970)

* Implements dynamic nominations per nominator

* Adds SnapshotBounds and ElectionSizeTracker

* Changes the ElectionDataProvider interface to receive ElectionBounds as input

* Implements get_npos_voters with ElectionBounds

* Implements get_npos_targets with ElectionBounds

* Adds comments

* tests

* Truncates nomninations that exceed nominations quota; Old tests passing

* Uses DataProviderBounds and ElectionBounds (to continue)

* Finishes conversions - tests passing

* Refactor staking in babe mocks

* Replaces MaxElectableTargets and MaxElectingVoters with ElectionBounds; Adds more tests

* Fixes nits; node compiling

* bechmarks

* removes nomination_quota extrinsic to request the nomination quota

* Lazy quota check, ie. at nominate time only

* remove non-working test (for now)

* tests lazy nominations quota when quota is lower than current number of nominated targets

* Adds runtime API and custom RPC call for clients to query the nominations quota for a given balance

* removes old rpc

* Cosmetic touches

* All mocks working

* Fixes benchmarking mocks

* nits

* more tests

* renames trait methods

* nit

* ".git/.scripts/commands/fmt/fmt.sh"

* Fix V2 PoV benchmarking (#13485)

* Bump default 'additional_trie_layers' to two

The default here only works for extremely small runtimes, which have
no more than 16 storage prefices. This is changed to a "sane" default
of 2, which is save for runtimes with up to 4096 storage prefices (eg StorageValue).

Signed-off-by: Oliver Tale-Yazdi <oliver.tale-yazdi@parity.io>

* Update tests and test weights

Signed-off-by: Oliver Tale-Yazdi <oliver.tale-yazdi@parity.io>

* Fix PoV weights

Signed-off-by: Oliver Tale-Yazdi <oliver.tale-yazdi@parity.io>

* ".git/.scripts/commands/bench/bench.sh" pallet dev pallet_balances

* ".git/.scripts/commands/bench/bench.sh" pallet dev pallet_message_queue

* ".git/.scripts/commands/bench/bench.sh" pallet dev pallet_glutton

* ".git/.scripts/commands/bench/bench.sh" pallet dev pallet_glutton

* Fix sanity check

>0 would also do as a check, but let's try this.

Signed-off-by: Oliver Tale-Yazdi <oliver.tale-yazdi@parity.io>

---------

Signed-off-by: Oliver Tale-Yazdi <oliver.tale-yazdi@parity.io>
Co-authored-by: command-bot <>

* Move BEEFY code to consensus (#13484)

* Move beefy primitives to consensus dir
* Move beefy gadget to client consensus folder
* Rename beefy crates

* chore: move genesis block builder to chain-spec crate. (#13427)

* chore: move genesis block builder to block builder crate.

* add missing file

* chore: move genesis block builder to sc-chain-spec

* Update client/chain-spec/src/genesis.rs

Co-authored-by: Bastian Köcher <git@kchr.de>

* Update test-utils/runtime/src/genesismap.rs

Co-authored-by: Bastian Köcher <git@kchr.de>

* Update test-utils/runtime/client/src/lib.rs

* fix warnings

* fix warnings

---------

Co-authored-by: Bastian Köcher <git@kchr.de>

* Speed up storage iteration from within the runtime (#13479)

* Speed up storage iteration from within the runtime

* Move the cached iterator into an `Option`

* Use `RefCell` in no_std

* Simplify the code slightly

* Use `Option::replace`

* Update doc comment for `next_storage_key_slow`

* Make unbounded channels size warning exact (part 1) (#13490)

* Replace `futures-channel` with `async-channel` in `out_events`

* Apply suggestions from code review

Co-authored-by: Koute <koute@users.noreply.github.com>

* Also print the backtrace of `send()` call

* Switch from `backtrace` crate to `std::backtrace`

* Remove outdated `backtrace` dependency

* Remove `backtrace` from `Cargo.lock`

---------

Co-authored-by: Koute <koute@users.noreply.github.com>

* Removal of Prometheus alerting rules deployment in cloud-infra (#13499)

* sp-consensus: remove unused error variants (#13495)

* Expose `ChargedAmount` (#13488)

* Expose `ChargedAmount`

* Fix imports

* sc-consensus-beefy: fix metrics: use correct names (#13494)


Signed-off-by: acatangiu <adrian@parity.io>

* clippy fix

* removes NominationsQuotaExceeded event

* Update frame/staking/src/lib.rs

Co-authored-by: Ross Bulat <ross@parity.io>

* adds back the npos_max_iter

* remove duplicate imports added after merge

* fmt

* Adds comment in public struct; Refactors CountBound and SizeCount to struct

* addresses various pr comments

* PR comment reviews

* Fixes on-chain election bounds and related code

* EPM checks the size of the voter list returned by the data provider

* cosmetic changes

* updates e2e tests mock

* Adds more tests for size tracker and refactors code

* Adds back only_iterates_max_2_times_max_allowed_len test

* Refactor

* removes unecessary dependency

* empty commit -- restart all stuck CI jobs

* restarts ci jobs

* Renames ElectionBounds -> Bounds in benchmarking mocks et al

* updates mocks

* Update frame/election-provider-support/src/lib.rs

Co-authored-by: Kian Paimani <5588131+kianenigma@users.noreply.github.com>

* Update frame/staking/src/pallet/impls.rs

Co-authored-by: Kian Paimani <5588131+kianenigma@users.noreply.github.com>

* Update frame/election-provider-support/src/lib.rs

Co-authored-by: Kian Paimani <5588131+kianenigma@users.noreply.github.com>

* Update frame/staking/src/tests.rs

Co-authored-by: Kian Paimani <5588131+kianenigma@users.noreply.github.com>

* more checks in api_nominations_quota in tests

* Improves docs

* fixes e2e tests

* Uses size_hint rather than mem::size_of in size tracker; Refactor size tracker to own module

* nits from reviews

* Refactors bounds to own module; improves docs

* More tests and docs

* fixes docs

* Fixes benchmarks

* Fixes rust docs

* fixes bags-list remote-ext-tests

* Simplify bound checks in create_snapshot_external

* Adds target size check in get_npos_targets

* ".git/.scripts/commands/fmt/fmt.sh"

* restart ci

* rust doc fixes and cosmetic nits

* rollback upgrade on parity-scale-codec version (unecessary)

* reset cargo lock, no need to update it

---------

Signed-off-by: Oliver Tale-Yazdi <oliver.tale-yazdi@parity.io>
Signed-off-by: acatangiu <adrian@parity.io>
Co-authored-by: command-bot <>
Co-authored-by: Oliver Tale-Yazdi <oliver.tale-yazdi@parity.io>
Co-authored-by: Davide Galassi <davxy@datawok.net>
Co-authored-by: yjh <yjh465402634@gmail.com>
Co-authored-by: Bastian Köcher <git@kchr.de>
Co-authored-by: Koute <koute@users.noreply.github.com>
Co-authored-by: Dmitry Markin <dmitry@markin.tech>
Co-authored-by: Anthony Lazam <lazam@users.noreply.github.com>
Co-authored-by: André Silva <123550+andresilva@users.noreply.github.com>
Co-authored-by: Piotr Mikołajczyk <piomiko41@gmail.com>
Co-authored-by: Adrian Catangiu <adrian@parity.io>
Co-authored-by: Ross Bulat <ross@parity.io>
Co-authored-by: Kian Paimani <5588131+kianenigma@users.noreply.github.com>

substrate/frame/staking/src/lib.rs

@@ -292,6 +292,7 @@ pub(crate) mod mock;
 #[cfg(test)]
 mod tests;
 
+pub mod election_size_tracker;
 pub mod inflation;
 pub mod migrations;
 pub mod slashing;
@@ -301,7 +302,7 @@ mod pallet;
 
 use codec::{Decode, Encode, HasCompact, MaxEncodedLen};
 use frame_support::{
-	traits::{Currency, Defensive, Get},
+	traits::{ConstU32, Currency, Defensive, Get},
 	weights::Weight,
 	BoundedVec, CloneNoBound, EqNoBound, PartialEqNoBound, RuntimeDebugNoBound,
 };
@@ -338,6 +339,10 @@ macro_rules! log {
 /// pallet.
 pub type MaxWinnersOf<T> = <<T as Config>::ElectionProvider as frame_election_provider_support::ElectionProviderBase>::MaxWinners;
 
+/// Maximum number of nominations per nominator.
+pub type MaxNominationsOf<T> =
+	<<T as Config>::NominationsQuota as NominationsQuota<BalanceOf<T>>>::MaxNominations;
+
 /// Counter for the number of "reward" points earned by a given validator.
 pub type RewardPoint = u32;
 
@@ -679,7 +684,7 @@ impl<T: Config> StakingLedger<T> {
 #[scale_info(skip_type_params(T))]
 pub struct Nominations<T: Config> {
 	/// The targets of nomination.
-	pub targets: BoundedVec<T::AccountId, T::MaxNominations>,
+	pub targets: BoundedVec<T::AccountId, MaxNominationsOf<T>>,
 	/// The era the nominations were submitted.
 	///
 	/// Except for initial nominations which are considered submitted at era 0.
@@ -749,6 +754,36 @@ impl<AccountId, Balance: HasCompact + Zero> UnappliedSlash<AccountId, Balance> {
 	}
 }
 
+/// Something that defines the maximum number of nominations per nominator based on a curve.
+///
+/// The method `curve` implements the nomination quota curve and should not be used directly.
+/// However, `get_quota` returns the bounded maximum number of nominations based on `fn curve` and
+/// the nominator's balance.
+pub trait NominationsQuota<Balance> {
+	/// Strict maximum number of nominations that caps the nominations curve. This value can be
+	/// used as the upper bound of the number of votes per nominator.
+	type MaxNominations: Get<u32>;
+
+	/// Returns the voter's nomination quota within reasonable bounds [`min`, `max`], where `min`
+	/// is 1 and `max` is `Self::MaxNominations`.
+	fn get_quota(balance: Balance) -> u32 {
+		Self::curve(balance).clamp(1, Self::MaxNominations::get())
+	}
+
+	/// Returns the voter's nomination quota based on its balance and a curve.
+	fn curve(balance: Balance) -> u32;
+}
+
+/// A nomination quota that allows up to MAX nominations for all validators.
+pub struct FixedNominationsQuota<const MAX: u32>;
+impl<Balance, const MAX: u32> NominationsQuota<Balance> for FixedNominationsQuota<MAX> {
+	type MaxNominations = ConstU32<MAX>;
+
+	fn curve(_: Balance) -> u32 {
+		MAX
+	}
+}
+
 /// Means for interacting with a specialized version of the `session` trait.
 ///
 /// This is needed because `Staking` sets the `ValidatorIdOf` of the `pallet_session::Config`