Fast Unstake Pallet (#12129)

* add failing test for itamar

* an ugly example of fast unstake

* Revert "add failing test for itamar"

This reverts commit 16c4d8015698a0684c090c54fce8b470a2d2feb2.

* fast unstake wip

* clean it up a bit

* some comments

* on_idle logic

* fix

* comment

* new working version, checks all pass, looking good

* some notes

* add mock boilerplate

* more boilerplate

* simplify the weight stuff

* ExtBuilder for pools

* fmt

* rm bags-list, simplify setup_works

* mock + tests boilerplate

* make some benchmarks work

* mock boilerplate

* tests boilerplate

* run_to_block works

* add Error enums

* add test

* note

* make UnstakeRequest fields pub

* some tests

* fix origin

* fmt

* add fast_unstake_events_since_last_call

* text

* rewrite some benchmes and fix them -- the outcome is still strange

* Fix weights

* cleanup

* Update frame/election-provider-support/solution-type/src/single_page.rs

* fix build

* Fix pools tests

* iterate teset + mock

* test unfinished

* cleanup and add some tests

* add test successful_multi_queue

* comment

* rm Head check

* add TODO

* complete successful_multi_queue

* + test early_exit

* fix a lot of things above the beautiful atlantic ocean 🌊

* seemingly it is finished now

* Fix build

* ".git/.scripts/fmt.sh" 1

* Fix slashing amount as well

* better docs

* abstract types

* rm use

* import

* Update frame/nomination-pools/benchmarking/src/lib.rs

Co-authored-by: Nitwit <47109040+nitwit69@users.noreply.github.com>

* Update frame/fast-unstake/src/types.rs

Co-authored-by: Nitwit <47109040+nitwit69@users.noreply.github.com>

* Fix build

* fmt

* Update frame/fast-unstake/src/lib.rs

Co-authored-by: Keith Yeung <kungfukeith11@gmail.com>

* make bounded

* feedback from code review with Ankan

* Update frame/fast-unstake/src/lib.rs

Co-authored-by: Roman Useinov <roman.useinov@gmail.com>

* Update frame/fast-unstake/src/lib.rs

Co-authored-by: Roman Useinov <roman.useinov@gmail.com>

* Update frame/fast-unstake/src/lib.rs

Co-authored-by: Roman Useinov <roman.useinov@gmail.com>

* Update frame/fast-unstake/src/lib.rs

Co-authored-by: Roman Useinov <roman.useinov@gmail.com>

* Update frame/fast-unstake/src/lib.rs

Co-authored-by: Roman Useinov <roman.useinov@gmail.com>

* Update frame/fast-unstake/src/lib.rs

Co-authored-by: Roman Useinov <roman.useinov@gmail.com>

* Update frame/fast-unstake/src/lib.rs

Co-authored-by: Roman Useinov <roman.useinov@gmail.com>

* Update frame/fast-unstake/src/lib.rs

Co-authored-by: Roman Useinov <roman.useinov@gmail.com>

* Update frame/fast-unstake/src/lib.rs

Co-authored-by: Roman Useinov <roman.useinov@gmail.com>

* Update frame/fast-unstake/src/mock.rs

* update to master

* some final review comments

* fmt

* fix clippy

* remove unused

* ".git/.scripts/fmt.sh" 1

* make it all build again

* fmt

* undo fishy change

Co-authored-by: Ross Bulat <ross@jkrbinvestments.com>
Co-authored-by: command-bot <>
Co-authored-by: Nitwit <47109040+nitwit69@users.noreply.github.com>
Co-authored-by: Keith Yeung <kungfukeith11@gmail.com>
Co-authored-by: Roman Useinov <roman.useinov@gmail.com>

substrate/frame/staking/src/lib.rs

@@ -563,7 +563,7 @@ impl<T: Config> StakingLedger<T> {
 	///
 	/// This calls `Config::OnStakerSlash::on_slash` with information as to how the slash was
 	/// applied.
-	fn slash(
+	pub fn slash(
 		&mut self,
 		slash_amount: BalanceOf<T>,
 		minimum_balance: BalanceOf<T>,

substrate/frame/staking/src/pallet/impls.rs

@@ -653,10 +653,10 @@ impl<T: Config> Pallet<T> {
 	#[cfg(feature = "runtime-benchmarks")]
 	pub fn add_era_stakers(
 		current_era: EraIndex,
-		controller: T::AccountId,
+		stash: T::AccountId,
 		exposure: Exposure<T::AccountId, BalanceOf<T>>,
 	) {
-		<ErasStakers<T>>::insert(&current_era, &controller, &exposure);
+		<ErasStakers<T>>::insert(&current_era, &stash, &exposure);
 	}
 
 	#[cfg(feature = "runtime-benchmarks")]

substrate/frame/staking/src/pallet/mod.rs

@@ -504,6 +504,7 @@ pub mod pallet {
 
 	/// Slashing spans for stash accounts.
 	#[pallet::storage]
+	#[pallet::getter(fn slashing_spans)]
 	#[pallet::unbounded]
 	pub(crate) type SlashingSpans<T: Config> =
 		StorageMap<_, Twox64Concat, T::AccountId, slashing::SlashingSpans>;
@@ -656,8 +657,8 @@ pub mod pallet {
 		EraPaid(EraIndex, BalanceOf<T>, BalanceOf<T>),
 		/// The nominator has been rewarded by this amount. \[stash, amount\]
 		Rewarded(T::AccountId, BalanceOf<T>),
-		/// One validator (and its nominators) has been slashed by the given amount.
-		/// \[validator, amount\]
+		/// One staker (and potentially its nominators) has been slashed by the given amount.
+		/// \[staker, amount\]
 		Slashed(T::AccountId, BalanceOf<T>),
 		/// An old slashing report from a prior era was discarded because it could
 		/// not be processed. \[session_index\]