[Feature] Add deposit to fast-unstake (#12366)

* [Feature] Add deposit to fast-unstake

* disable on ErasToCheckPerBlock == 0

* removed signed ext

* remove obsolete import

* remove some obsolete stuff

* fix some comments

* fixed all the comments

* remove obsolete imports

* fix some tests

* CallNotAllowed tests

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

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

* fix tests

* fix deregister + tests

* more fixes

* make sure we go above existential deposit

* fixed the last test

* some nit fixes

* fix node

* fix bench

* last bench fix

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

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

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

substrate/bin/node/runtime/src/lib.rs

@@ -581,8 +581,9 @@ impl pallet_staking::Config for Runtime {
 
 impl pallet_fast_unstake::Config for Runtime {
 	type RuntimeEvent = RuntimeEvent;
-	type SlashPerEra = ConstU128<{ DOLLARS }>;
 	type ControlOrigin = frame_system::EnsureRoot<AccountId>;
+	type Deposit = ConstU128<{ DOLLARS }>;
+	type DepositCurrency = Balances;
 	type WeightInfo = ();
 }
 

substrate/frame/fast-unstake/src/benchmarking.rs

@@ -110,18 +110,18 @@ fn on_idle_full_block<T: Config>() {
 benchmarks! {
 	// on_idle, we we don't check anyone, but fully unbond and move them to another pool.
 	on_idle_unstake {
+		ErasToCheckPerBlock::<T>::put(1);
 		let who = create_unexposed_nominator::<T>();
 		assert_ok!(FastUnstake::<T>::register_fast_unstake(
 			RawOrigin::Signed(who.clone()).into(),
 		));
-		ErasToCheckPerBlock::<T>::put(1);
 
 		// run on_idle once. This will check era 0.
 		assert_eq!(Head::<T>::get(), None);
 		on_idle_full_block::<T>();
 		assert_eq!(
 			Head::<T>::get(),
-			Some(UnstakeRequest { stash: who.clone(), checked: vec![0].try_into().unwrap() })
+			Some(UnstakeRequest { stash: who.clone(), checked: vec![0].try_into().unwrap(), deposit: T::Deposit::get() })
 		);
 	}
 	: {
@@ -162,7 +162,7 @@ benchmarks! {
 		let checked: frame_support::BoundedVec<_, _> = (1..=u).rev().collect::<Vec<EraIndex>>().try_into().unwrap();
 		assert_eq!(
 			Head::<T>::get(),
-			Some(UnstakeRequest { stash: who.clone(), checked })
+			Some(UnstakeRequest { stash: who.clone(), checked, deposit: T::Deposit::get() })
 		);
 		assert!(matches!(
 			fast_unstake_events::<T>().last(),
@@ -171,6 +171,7 @@ benchmarks! {
 	}
 
 	register_fast_unstake {
+		ErasToCheckPerBlock::<T>::put(1);
 		let who = create_unexposed_nominator::<T>();
 		whitelist_account!(who);
 		assert_eq!(Queue::<T>::count(), 0);
@@ -182,6 +183,7 @@ benchmarks! {
 	}
 
 	deregister {
+		ErasToCheckPerBlock::<T>::put(1);
 		let who = create_unexposed_nominator::<T>();
 		assert_ok!(FastUnstake::<T>::register_fast_unstake(
 			RawOrigin::Signed(who.clone()).into(),

substrate/frame/fast-unstake/src/lib.rs

@@ -81,7 +81,10 @@ pub mod pallet {
 	use super::*;
 	use crate::types::*;
 	use frame_election_provider_support::ElectionProvider;
-	use frame_support::pallet_prelude::*;
+	use frame_support::{
+		pallet_prelude::*,
+		traits::{Defensive, ReservableCurrency},
+	};
 	use frame_system::{pallet_prelude::*, RawOrigin};
 	use pallet_staking::Pallet as Staking;
 	use sp_runtime::{
@@ -90,7 +93,6 @@ pub mod pallet {
 	};
 	use sp_staking::EraIndex;
 	use sp_std::{prelude::*, vec::Vec};
-	pub use types::PreventStakingOpsIfUnbonding;
 	pub use weights::WeightInfo;
 
 	#[derive(scale_info::TypeInfo, codec::Encode, codec::Decode, codec::MaxEncodedLen)]
@@ -113,10 +115,12 @@ pub mod pallet {
 			+ IsType<<Self as frame_system::Config>::RuntimeEvent>
 			+ TryInto<Event<Self>>;
 
-		/// The amount of balance slashed per each era that was wastefully checked.
-		///
-		/// A reasonable value could be `runtime_weight_to_fee(weight_per_era_check)`.
-		type SlashPerEra: Get<BalanceOf<Self>>;
+		/// The currency used for deposits.
+		type DepositCurrency: ReservableCurrency<Self::AccountId, Balance = BalanceOf<Self>>;
+
+		/// Deposit to take for unstaking, to make sure we're able to slash the it in order to cover
+		/// the costs of resources on unsuccessful unstake.
+		type Deposit: Get<BalanceOf<Self>>;
 
 		/// The origin that can control this pallet.
 		type ControlOrigin: frame_support::traits::EnsureOrigin<Self::RuntimeOrigin>;
@@ -128,13 +132,13 @@ pub mod pallet {
 	/// The current "head of the queue" being unstaked.
 	#[pallet::storage]
 	pub type Head<T: Config> =
-		StorageValue<_, UnstakeRequest<T::AccountId, MaxChecking<T>>, OptionQuery>;
+		StorageValue<_, UnstakeRequest<T::AccountId, MaxChecking<T>, BalanceOf<T>>, OptionQuery>;
 
 	/// The map of all accounts wishing to be unstaked.
 	///
-	/// Keeps track of `AccountId` wishing to unstake.
+	/// Keeps track of `AccountId` wishing to unstake and it's corresponding deposit.
 	#[pallet::storage]
-	pub type Queue<T: Config> = CountedStorageMap<_, Twox64Concat, T::AccountId, ()>;
+	pub type Queue<T: Config> = CountedStorageMap<_, Twox64Concat, T::AccountId, BalanceOf<T>>;
 
 	/// Number of eras to check per block.
 	///
@@ -177,6 +181,8 @@ pub mod pallet {
 		NotQueued,
 		/// The provided un-staker is already in Head, and cannot deregister.
 		AlreadyHead,
+		/// The call is not allowed at this point because the pallet is not active.
+		CallNotAllowed,
 	}
 
 	#[pallet::hooks]
@@ -214,6 +220,8 @@ pub mod pallet {
 		pub fn register_fast_unstake(origin: OriginFor<T>) -> DispatchResult {
 			let ctrl = ensure_signed(origin)?;
 
+			ensure!(ErasToCheckPerBlock::<T>::get() != 0, <Error<T>>::CallNotAllowed);
+
 			let ledger =
 				pallet_staking::Ledger::<T>::get(&ctrl).ok_or(Error::<T>::NotController)?;
 			ensure!(!Queue::<T>::contains_key(&ledger.stash), Error::<T>::AlreadyQueued);
@@ -231,8 +239,10 @@ pub mod pallet {
 			Staking::<T>::chill(RawOrigin::Signed(ctrl.clone()).into())?;
 			Staking::<T>::unbond(RawOrigin::Signed(ctrl).into(), ledger.total)?;
 
+			T::DepositCurrency::reserve(&ledger.stash, T::Deposit::get())?;
+
 			// enqueue them.
-			Queue::<T>::insert(ledger.stash, ());
+			Queue::<T>::insert(ledger.stash, T::Deposit::get());
 			Ok(())
 		}
 
@@ -246,6 +256,9 @@ pub mod pallet {
 		#[pallet::weight(<T as Config>::WeightInfo::deregister())]
 		pub fn deregister(origin: OriginFor<T>) -> DispatchResult {
 			let ctrl = ensure_signed(origin)?;
+
+			ensure!(ErasToCheckPerBlock::<T>::get() != 0, <Error<T>>::CallNotAllowed);
+
 			let stash = pallet_staking::Ledger::<T>::get(&ctrl)
 				.map(|l| l.stash)
 				.ok_or(Error::<T>::NotController)?;
@@ -254,7 +267,17 @@ pub mod pallet {
 				Head::<T>::get().map_or(true, |UnstakeRequest { stash, .. }| stash != stash),
 				Error::<T>::AlreadyHead
 			);
-			Queue::<T>::remove(stash);
+			let deposit = Queue::<T>::take(stash.clone());
+
+			if let Some(deposit) = deposit.defensive() {
+				let remaining = T::DepositCurrency::unreserve(&stash, deposit);
+				if !remaining.is_zero() {
+					frame_support::defensive!("`not enough balance to unreserve`");
+					ErasToCheckPerBlock::<T>::put(0);
+					Self::deposit_event(Event::<T>::InternalError)
+				}
+			}
+
 			Ok(())
 		}
 
@@ -315,18 +338,23 @@ pub mod pallet {
 				return T::DbWeight::get().reads(2)
 			}
 
-			let UnstakeRequest { stash, mut checked } = match Head::<T>::take().or_else(|| {
-				// NOTE: there is no order guarantees in `Queue`.
-				Queue::<T>::drain()
-					.map(|(stash, _)| UnstakeRequest { stash, checked: Default::default() })
-					.next()
-			}) {
-				None => {
-					// There's no `Head` and nothing in the `Queue`, nothing to do here.
-					return T::DbWeight::get().reads(4)
-				},
-				Some(head) => head,
-			};
+			let UnstakeRequest { stash, mut checked, deposit } =
+				match Head::<T>::take().or_else(|| {
+					// NOTE: there is no order guarantees in `Queue`.
+					Queue::<T>::drain()
+						.map(|(stash, deposit)| UnstakeRequest {
+							stash,
+							deposit,
+							checked: Default::default(),
+						})
+						.next()
+				}) {
+					None => {
+						// There's no `Head` and nothing in the `Queue`, nothing to do here.
+						return T::DbWeight::get().reads(4)
+					},
+					Some(head) => head,
+				};
 
 			log!(
 				debug,
@@ -381,9 +409,16 @@ pub mod pallet {
 					num_slashing_spans,
 				);
 
-				log!(info, "unstaked {:?}, outcome: {:?}", stash, result);
+				let remaining = T::DepositCurrency::unreserve(&stash, deposit);
+				if !remaining.is_zero() {
+					frame_support::defensive!("`not enough balance to unreserve`");
+					ErasToCheckPerBlock::<T>::put(0);
+					Self::deposit_event(Event::<T>::InternalError)
+				} else {
+					log!(info, "unstaked {:?}, outcome: {:?}", stash, result);
+					Self::deposit_event(Event::<T>::Unstaked { stash, result });
+				}
 
-				Self::deposit_event(Event::<T>::Unstaked { stash, result });
 				<T as Config>::WeightInfo::on_idle_unstake()
 			} else {
 				// eras remaining to be checked.
@@ -406,22 +441,18 @@ pub mod pallet {
 				// the last 28 eras, have registered yourself to be unstaked, midway being checked,
 				// you are exposed.
 				if is_exposed {
-					let amount = T::SlashPerEra::get()
-						.saturating_mul(eras_checked.saturating_add(checked.len() as u32).into());
-					pallet_staking::slashing::do_slash::<T>(
-						&stash,
-						amount,
-						&mut Default::default(),
-						&mut Default::default(),
-						current_era,
-					);
-					log!(info, "slashed {:?} by {:?}", stash, amount);
-					Self::deposit_event(Event::<T>::Slashed { stash, amount });
+					T::DepositCurrency::slash_reserved(&stash, deposit);
+					log!(info, "slashed {:?} by {:?}", stash, deposit);
+					Self::deposit_event(Event::<T>::Slashed { stash, amount: deposit });
 				} else {
 					// Not exposed in these eras.
 					match checked.try_extend(unchecked_eras_to_check.clone().into_iter()) {
 						Ok(_) => {
-							Head::<T>::put(UnstakeRequest { stash: stash.clone(), checked });
+							Head::<T>::put(UnstakeRequest {
+								stash: stash.clone(),
+								checked,
+								deposit,
+							});
 							Self::deposit_event(Event::<T>::Checking {
 								stash,
 								eras: unchecked_eras_to_check,

substrate/frame/fast-unstake/src/mock.rs

@@ -164,12 +164,13 @@ impl Convert<sp_core::U256, Balance> for U256ToBalance {
 }
 
 parameter_types! {
-	pub static SlashPerEra: u32 = 100;
+	pub static DepositAmount: u128 = 7;
 }
 
 impl fast_unstake::Config for Runtime {
 	type RuntimeEvent = RuntimeEvent;
-	type SlashPerEra = SlashPerEra;
+	type Deposit = DepositAmount;
+	type DepositCurrency = Balances;
 	type ControlOrigin = frame_system::EnsureRoot<Self::AccountId>;
 	type WeightInfo = ();
 }
@@ -213,11 +214,11 @@ impl Default for ExtBuilder {
 	fn default() -> Self {
 		Self {
 			exposed_nominators: vec![
-				(1, 2, 100),
-				(3, 4, 100),
-				(5, 6, 100),
-				(7, 8, 100),
-				(9, 10, 100),
+				(1, 2, 7 + 100),
+				(3, 4, 7 + 100),
+				(5, 6, 7 + 100),
+				(7, 8, 7 + 100),
+				(9, 10, 7 + 100),
 			],
 		}
 	}
@@ -270,8 +271,8 @@ impl ExtBuilder {
 						.into_iter()
 						.map(|(_, ctrl, balance)| (ctrl, balance * 2)),
 				)
-				.chain(validators_range.clone().map(|x| (x, 100)))
-				.chain(nominators_range.clone().map(|x| (x, 100)))
+				.chain(validators_range.clone().map(|x| (x, 7 + 100)))
+				.chain(nominators_range.clone().map(|x| (x, 7 + 100)))
 				.collect::<Vec<_>>(),
 		}
 		.assimilate_storage(&mut storage);

substrate/frame/fast-unstake/src/tests.rs

@@ -35,6 +35,7 @@ fn test_setup_works() {
 #[test]
 fn register_works() {
 	ExtBuilder::default().build_and_execute(|| {
+		ErasToCheckPerBlock::<T>::put(1);
 		// Controller account registers for fast unstake.
 		assert_ok!(FastUnstake::register_fast_unstake(RuntimeOrigin::signed(2)));
 		// Ensure stash is in the queue.
@@ -42,9 +43,38 @@ fn register_works() {
 	});
 }
 
+#[test]
+fn register_insufficient_funds_fails() {
+	use pallet_balances::Error as BalancesError;
+	ExtBuilder::default().build_and_execute(|| {
+		ErasToCheckPerBlock::<T>::put(1);
+		<T as Config>::DepositCurrency::make_free_balance_be(&1, 3);
+
+		// Controller account registers for fast unstake.
+		assert_noop!(
+			FastUnstake::register_fast_unstake(RuntimeOrigin::signed(2)),
+			BalancesError::<T, _>::InsufficientBalance,
+		);
+
+		// Ensure stash is in the queue.
+		assert_eq!(Queue::<T>::get(1), None);
+	});
+}
+
+#[test]
+fn register_disabled_fails() {
+	ExtBuilder::default().build_and_execute(|| {
+		assert_noop!(
+			FastUnstake::register_fast_unstake(RuntimeOrigin::signed(2)),
+			Error::<T>::CallNotAllowed
+		);
+	});
+}
+
 #[test]
 fn cannot_register_if_not_bonded() {
 	ExtBuilder::default().build_and_execute(|| {
+		ErasToCheckPerBlock::<T>::put(1);
 		// Mint accounts 1 and 2 with 200 tokens.
 		for _ in 1..2 {
 			let _ = Balances::make_free_balance_be(&1, 200);
@@ -60,8 +90,9 @@ fn cannot_register_if_not_bonded() {
 #[test]
 fn cannot_register_if_in_queue() {
 	ExtBuilder::default().build_and_execute(|| {
+		ErasToCheckPerBlock::<T>::put(1);
 		// Insert some Queue item
-		Queue::<T>::insert(1, ());
+		Queue::<T>::insert(1, 10);
 		// Cannot re-register, already in queue
 		assert_noop!(
 			FastUnstake::register_fast_unstake(RuntimeOrigin::signed(2)),
@@ -73,8 +104,13 @@ fn cannot_register_if_in_queue() {
 #[test]
 fn cannot_register_if_head() {
 	ExtBuilder::default().build_and_execute(|| {
+		ErasToCheckPerBlock::<T>::put(1);
 		// Insert some Head item for stash
-		Head::<T>::put(UnstakeRequest { stash: 1, checked: bounded_vec![] });
+		Head::<T>::put(UnstakeRequest {
+			stash: 1,
+			checked: bounded_vec![],
+			deposit: DepositAmount::get(),
+		});
 		// Controller attempts to regsiter
 		assert_noop!(
 			FastUnstake::register_fast_unstake(RuntimeOrigin::signed(2)),
@@ -86,6 +122,7 @@ fn cannot_register_if_head() {
 #[test]
 fn cannot_register_if_has_unlocking_chunks() {
 	ExtBuilder::default().build_and_execute(|| {
+		ErasToCheckPerBlock::<T>::put(1);
 		// Start unbonding half of staked tokens
 		assert_ok!(Staking::unbond(RuntimeOrigin::signed(2), 50_u128));
 		// Cannot register for fast unstake with unlock chunks active
@@ -99,18 +136,37 @@ fn cannot_register_if_has_unlocking_chunks() {
 #[test]
 fn deregister_works() {
 	ExtBuilder::default().build_and_execute(|| {
+		ErasToCheckPerBlock::<T>::put(1);
+
+		assert_eq!(<T as Config>::DepositCurrency::reserved_balance(&1), 0);
+
 		// Controller account registers for fast unstake.
 		assert_ok!(FastUnstake::register_fast_unstake(RuntimeOrigin::signed(2)));
+		assert_eq!(<T as Config>::DepositCurrency::reserved_balance(&1), DepositAmount::get());
+
 		// Controller then changes mind and deregisters.
 		assert_ok!(FastUnstake::deregister(RuntimeOrigin::signed(2)));
+		assert_eq!(<T as Config>::DepositCurrency::reserved_balance(&1), 0);
+
 		// Ensure stash no longer exists in the queue.
 		assert_eq!(Queue::<T>::get(1), None);
 	});
 }
 
+#[test]
+fn deregister_disabled_fails() {
+	ExtBuilder::default().build_and_execute(|| {
+		ErasToCheckPerBlock::<T>::put(1);
+		assert_ok!(FastUnstake::register_fast_unstake(RuntimeOrigin::signed(2)));
+		ErasToCheckPerBlock::<T>::put(0);
+		assert_noop!(FastUnstake::deregister(RuntimeOrigin::signed(2)), Error::<T>::CallNotAllowed);
+	});
+}
+
 #[test]
 fn cannot_deregister_if_not_controller() {
 	ExtBuilder::default().build_and_execute(|| {
+		ErasToCheckPerBlock::<T>::put(1);
 		// Controller account registers for fast unstake.
 		assert_ok!(FastUnstake::register_fast_unstake(RuntimeOrigin::signed(2)));
 		// Stash tries to deregister.
@@ -121,6 +177,7 @@ fn cannot_deregister_if_not_controller() {
 #[test]
 fn cannot_deregister_if_not_queued() {
 	ExtBuilder::default().build_and_execute(|| {
+		ErasToCheckPerBlock::<T>::put(1);
 		// Controller tries to deregister without first registering
 		assert_noop!(FastUnstake::deregister(RuntimeOrigin::signed(2)), Error::<T>::NotQueued);
 	});
@@ -129,10 +186,15 @@ fn cannot_deregister_if_not_queued() {
 #[test]
 fn cannot_deregister_already_head() {
 	ExtBuilder::default().build_and_execute(|| {
+		ErasToCheckPerBlock::<T>::put(1);
 		// Controller attempts to register, should fail
 		assert_ok!(FastUnstake::register_fast_unstake(RuntimeOrigin::signed(2)));
 		// Insert some Head item for stash.
-		Head::<T>::put(UnstakeRequest { stash: 1, checked: bounded_vec![] });
+		Head::<T>::put(UnstakeRequest {
+			stash: 1,
+			checked: bounded_vec![],
+			deposit: DepositAmount::get(),
+		});
 		// Controller attempts to deregister
 		assert_noop!(FastUnstake::deregister(RuntimeOrigin::signed(2)), Error::<T>::AlreadyHead);
 	});
@@ -165,14 +227,14 @@ mod on_idle {
 
 			// set up Queue item
 			assert_ok!(FastUnstake::register_fast_unstake(RuntimeOrigin::signed(2)));
-			assert_eq!(Queue::<T>::get(1), Some(()));
+			assert_eq!(Queue::<T>::get(1), Some(DepositAmount::get()));
 
 			// call on_idle with no remaining weight
 			FastUnstake::on_idle(System::block_number(), Weight::from_ref_time(0));
 
 			// assert nothing changed in Queue and Head
 			assert_eq!(Head::<T>::get(), None);
-			assert_eq!(Queue::<T>::get(1), Some(()));
+			assert_eq!(Queue::<T>::get(1), Some(DepositAmount::get()));
 		});
 	}
 
@@ -185,7 +247,7 @@ mod on_idle {
 
 			// given
 			assert_ok!(FastUnstake::register_fast_unstake(RuntimeOrigin::signed(2)));
-			assert_eq!(Queue::<T>::get(1), Some(()));
+			assert_eq!(Queue::<T>::get(1), Some(DepositAmount::get()));
 
 			assert_eq!(Queue::<T>::count(), 1);
 			assert_eq!(Head::<T>::get(), None);
@@ -204,7 +266,11 @@ mod on_idle {
 			);
 			assert_eq!(
 				Head::<T>::get(),
-				Some(UnstakeRequest { stash: 1, checked: bounded_vec![3] })
+				Some(UnstakeRequest {
+					deposit: DepositAmount::get(),
+					stash: 1,
+					checked: bounded_vec![3]
+				})
 			);
 
 			// when: another 1 era.
@@ -220,7 +286,11 @@ mod on_idle {
 			);
 			assert_eq!(
 				Head::<T>::get(),
-				Some(UnstakeRequest { stash: 1, checked: bounded_vec![3, 2] })
+				Some(UnstakeRequest {
+					deposit: DepositAmount::get(),
+					stash: 1,
+					checked: bounded_vec![3, 2]
+				})
 			);
 
 			// when: then 5 eras, we only need 2 more.
@@ -242,7 +312,11 @@ mod on_idle {
 			);
 			assert_eq!(
 				Head::<T>::get(),
-				Some(UnstakeRequest { stash: 1, checked: bounded_vec![3, 2, 1, 0] })
+				Some(UnstakeRequest {
+					deposit: DepositAmount::get(),
+					stash: 1,
+					checked: bounded_vec![3, 2, 1, 0]
+				})
 			);
 
 			// when: not enough weight to unstake:
@@ -254,7 +328,11 @@ mod on_idle {
 			assert_eq!(fast_unstake_events_since_last_call(), vec![]);
 			assert_eq!(
 				Head::<T>::get(),
-				Some(UnstakeRequest { stash: 1, checked: bounded_vec![3, 2, 1, 0] })
+				Some(UnstakeRequest {
+					deposit: DepositAmount::get(),
+					stash: 1,
+					checked: bounded_vec![3, 2, 1, 0]
+				})
 			);
 
 			// when: enough weight to get over at least one iteration: then we are unblocked and can
@@ -285,12 +363,16 @@ mod on_idle {
 			CurrentEra::<T>::put(BondingDuration::get());
 
 			// given
+			assert_eq!(<T as Config>::DepositCurrency::reserved_balance(&1), 0);
+
 			assert_ok!(FastUnstake::register_fast_unstake(RuntimeOrigin::signed(2)));
 			assert_ok!(FastUnstake::register_fast_unstake(RuntimeOrigin::signed(4)));
 			assert_ok!(FastUnstake::register_fast_unstake(RuntimeOrigin::signed(6)));
 			assert_ok!(FastUnstake::register_fast_unstake(RuntimeOrigin::signed(8)));
 			assert_ok!(FastUnstake::register_fast_unstake(RuntimeOrigin::signed(10)));
 
+			assert_eq!(<T as Config>::DepositCurrency::reserved_balance(&1), DepositAmount::get());
+
 			assert_eq!(Queue::<T>::count(), 5);
 			assert_eq!(Head::<T>::get(), None);
 
@@ -300,7 +382,11 @@ mod on_idle {
 			// then
 			assert_eq!(
 				Head::<T>::get(),
-				Some(UnstakeRequest { stash: 1, checked: bounded_vec![3, 2, 1, 0] })
+				Some(UnstakeRequest {
+					deposit: DepositAmount::get(),
+					stash: 1,
+					checked: bounded_vec![3, 2, 1, 0]
+				})
 			);
 			assert_eq!(Queue::<T>::count(), 4);
 
@@ -317,10 +403,16 @@ mod on_idle {
 			// then
 			assert_eq!(
 				Head::<T>::get(),
-				Some(UnstakeRequest { stash: 5, checked: bounded_vec![3, 2, 1, 0] }),
+				Some(UnstakeRequest {
+					deposit: DepositAmount::get(),
+					stash: 5,
+					checked: bounded_vec![3, 2, 1, 0]
+				}),
 			);
 			assert_eq!(Queue::<T>::count(), 3);
 
+			assert_eq!(<T as Config>::DepositCurrency::reserved_balance(&1), 0);
+
 			assert_eq!(
 				fast_unstake_events_since_last_call(),
 				vec![
@@ -340,9 +432,9 @@ mod on_idle {
 
 			// register multi accounts for fast unstake
 			assert_ok!(FastUnstake::register_fast_unstake(RuntimeOrigin::signed(2)));
-			assert_eq!(Queue::<T>::get(1), Some(()));
+			assert_eq!(Queue::<T>::get(1), Some(DepositAmount::get()));
 			assert_ok!(FastUnstake::register_fast_unstake(RuntimeOrigin::signed(4)));
-			assert_eq!(Queue::<T>::get(3), Some(()));
+			assert_eq!(Queue::<T>::get(3), Some(DepositAmount::get()));
 
 			// assert 2 queue items are in Queue & None in Head to start with
 			assert_eq!(Queue::<T>::count(), 2);
@@ -391,7 +483,7 @@ mod on_idle {
 
 			// register for fast unstake
 			assert_ok!(FastUnstake::register_fast_unstake(RuntimeOrigin::signed(2)));
-			assert_eq!(Queue::<T>::get(1), Some(()));
+			assert_eq!(Queue::<T>::get(1), Some(DepositAmount::get()));
 
 			// process on idle
 			next_block(true);
@@ -402,7 +494,11 @@ mod on_idle {
 			// assert head item present
 			assert_eq!(
 				Head::<T>::get(),
-				Some(UnstakeRequest { stash: 1, checked: bounded_vec![3, 2, 1, 0] })
+				Some(UnstakeRequest {
+					deposit: DepositAmount::get(),
+					stash: 1,
+					checked: bounded_vec![3, 2, 1, 0]
+				})
 			);
 
 			next_block(true);
@@ -425,9 +521,11 @@ mod on_idle {
 			ErasToCheckPerBlock::<T>::put(BondingDuration::get() + 1);
 			CurrentEra::<T>::put(BondingDuration::get());
 
+			Balances::make_free_balance_be(&2, 100);
+
 			// register for fast unstake
 			assert_ok!(FastUnstake::register_fast_unstake(RuntimeOrigin::signed(2)));
-			assert_eq!(Queue::<T>::get(1), Some(()));
+			assert_eq!(Queue::<T>::get(1), Some(DepositAmount::get()));
 
 			// process on idle
 			next_block(true);
@@ -438,7 +536,11 @@ mod on_idle {
 			// assert head item present
 			assert_eq!(
 				Head::<T>::get(),
-				Some(UnstakeRequest { stash: 1, checked: bounded_vec![3, 2, 1, 0] })
+				Some(UnstakeRequest {
+					deposit: DepositAmount::get(),
+					stash: 1,
+					checked: bounded_vec![3, 2, 1, 0]
+				})
 			);
 
 			next_block(true);
@@ -464,7 +566,7 @@ mod on_idle {
 
 			// register for fast unstake
 			assert_ok!(FastUnstake::register_fast_unstake(RuntimeOrigin::signed(2)));
-			assert_eq!(Queue::<T>::get(1), Some(()));
+			assert_eq!(Queue::<T>::get(1), Some(DepositAmount::get()));
 
 			// process on idle
 			next_block(true);
@@ -475,28 +577,44 @@ mod on_idle {
 			// assert head item present
 			assert_eq!(
 				Head::<T>::get(),
-				Some(UnstakeRequest { stash: 1, checked: bounded_vec![3] })
+				Some(UnstakeRequest {
+					deposit: DepositAmount::get(),
+					stash: 1,
+					checked: bounded_vec![3]
+				})
 			);
 
 			next_block(true);
 
 			assert_eq!(
 				Head::<T>::get(),
-				Some(UnstakeRequest { stash: 1, checked: bounded_vec![3, 2] })
+				Some(UnstakeRequest {
+					deposit: DepositAmount::get(),
+					stash: 1,
+					checked: bounded_vec![3, 2]
+				})
 			);
 
 			next_block(true);
 
 			assert_eq!(
 				Head::<T>::get(),
-				Some(UnstakeRequest { stash: 1, checked: bounded_vec![3, 2, 1] })
+				Some(UnstakeRequest {
+					deposit: DepositAmount::get(),
+					stash: 1,
+					checked: bounded_vec![3, 2, 1]
+				})
 			);
 
 			next_block(true);
 
 			assert_eq!(
 				Head::<T>::get(),
-				Some(UnstakeRequest { stash: 1, checked: bounded_vec![3, 2, 1, 0] })
+				Some(UnstakeRequest {
+					deposit: DepositAmount::get(),
+					stash: 1,
+					checked: bounded_vec![3, 2, 1, 0]
+				})
 			);
 
 			next_block(true);
@@ -529,30 +647,46 @@ mod on_idle {
 
 			// register for fast unstake
 			assert_ok!(FastUnstake::register_fast_unstake(RuntimeOrigin::signed(2)));
-			assert_eq!(Queue::<T>::get(1), Some(()));
+			assert_eq!(Queue::<T>::get(1), Some(DepositAmount::get()));
 
 			next_block(true);
 			assert_eq!(
 				Head::<T>::get(),
-				Some(UnstakeRequest { stash: 1, checked: bounded_vec![3] })
+				Some(UnstakeRequest {
+					deposit: DepositAmount::get(),
+					stash: 1,
+					checked: bounded_vec![3]
+				})
 			);
 
 			next_block(true);
 			assert_eq!(
 				Head::<T>::get(),
-				Some(UnstakeRequest { stash: 1, checked: bounded_vec![3, 2] })
+				Some(UnstakeRequest {
+					deposit: DepositAmount::get(),
+					stash: 1,
+					checked: bounded_vec![3, 2]
+				})
 			);
 
 			next_block(true);
 			assert_eq!(
 				Head::<T>::get(),
-				Some(UnstakeRequest { stash: 1, checked: bounded_vec![3, 2, 1] })
+				Some(UnstakeRequest {
+					deposit: DepositAmount::get(),
+					stash: 1,
+					checked: bounded_vec![3, 2, 1]
+				})
 			);
 
 			next_block(true);
 			assert_eq!(
 				Head::<T>::get(),
-				Some(UnstakeRequest { stash: 1, checked: bounded_vec![3, 2, 1, 0] })
+				Some(UnstakeRequest {
+					deposit: DepositAmount::get(),
+					stash: 1,
+					checked: bounded_vec![3, 2, 1, 0]
+				})
 			);
 
 			// when: a new era happens right before one is free.
@@ -567,6 +701,7 @@ mod on_idle {
 					stash: 1,
 					// note era 0 is pruned to keep the vector length sane.
 					checked: bounded_vec![3, 2, 1, 4],
+					deposit: DepositAmount::get(),
 				})
 			);
 
@@ -602,13 +737,21 @@ mod on_idle {
 			next_block(true);
 			assert_eq!(
 				Head::<T>::get(),
-				Some(UnstakeRequest { stash: 1, checked: bounded_vec![3] })
+				Some(UnstakeRequest {
+					deposit: DepositAmount::get(),
+					stash: 1,
+					checked: bounded_vec![3]
+				})
 			);
 
 			next_block(true);
 			assert_eq!(
 				Head::<T>::get(),
-				Some(UnstakeRequest { stash: 1, checked: bounded_vec![3, 2] })
+				Some(UnstakeRequest {
+					deposit: DepositAmount::get(),
+					stash: 1,
+					checked: bounded_vec![3, 2]
+				})
 			);
 
 			// when
@@ -618,13 +761,21 @@ mod on_idle {
 			next_block(true);
 			assert_eq!(
 				Head::<T>::get(),
-				Some(UnstakeRequest { stash: 1, checked: bounded_vec![3, 2] })
+				Some(UnstakeRequest {
+					deposit: DepositAmount::get(),
+					stash: 1,
+					checked: bounded_vec![3, 2]
+				})
 			);
 
 			next_block(true);
 			assert_eq!(
 				Head::<T>::get(),
-				Some(UnstakeRequest { stash: 1, checked: bounded_vec![3, 2] })
+				Some(UnstakeRequest {
+					deposit: DepositAmount::get(),
+					stash: 1,
+					checked: bounded_vec![3, 2]
+				})
 			);
 
 			// then we register a new era.
@@ -636,14 +787,22 @@ mod on_idle {
 			next_block(true);
 			assert_eq!(
 				Head::<T>::get(),
-				Some(UnstakeRequest { stash: 1, checked: bounded_vec![3, 2, 4] })
+				Some(UnstakeRequest {
+					deposit: DepositAmount::get(),
+					stash: 1,
+					checked: bounded_vec![3, 2, 4]
+				})
 			);
 
 			// progress to end
 			next_block(true);
 			assert_eq!(
 				Head::<T>::get(),
-				Some(UnstakeRequest { stash: 1, checked: bounded_vec![3, 2, 4, 1] })
+				Some(UnstakeRequest {
+					deposit: DepositAmount::get(),
+					stash: 1,
+					checked: bounded_vec![3, 2, 4, 1]
+				})
 			);
 
 			// but notice that we don't care about era 0 instead anymore! we're done.
@@ -669,7 +828,6 @@ mod on_idle {
 	fn exposed_nominator_cannot_unstake() {
 		ExtBuilder::default().build_and_execute(|| {
 			ErasToCheckPerBlock::<T>::put(1);
-			SlashPerEra::set(7);
 			CurrentEra::<T>::put(BondingDuration::get());
 
 			// create an exposed nominator in era 1
@@ -686,6 +844,7 @@ mod on_idle {
 			));
 			assert_ok!(Staking::nominate(RuntimeOrigin::signed(exposed), vec![exposed]));
 
+			Balances::make_free_balance_be(&exposed, 100_000);
 			// register the exposed one.
 			assert_ok!(FastUnstake::register_fast_unstake(RuntimeOrigin::signed(exposed)));
 
@@ -693,23 +852,30 @@ mod on_idle {
 			next_block(true);
 			assert_eq!(
 				Head::<T>::get(),
-				Some(UnstakeRequest { stash: exposed, checked: bounded_vec![3] })
+				Some(UnstakeRequest {
+					deposit: DepositAmount::get(),
+					stash: exposed,
+					checked: bounded_vec![3]
+				})
 			);
 			next_block(true);
 			assert_eq!(
 				Head::<T>::get(),
-				Some(UnstakeRequest { stash: exposed, checked: bounded_vec![3, 2] })
+				Some(UnstakeRequest {
+					deposit: DepositAmount::get(),
+					stash: exposed,
+					checked: bounded_vec![3, 2]
+				})
 			);
 			next_block(true);
 			assert_eq!(Head::<T>::get(), None);
 
 			assert_eq!(
 				fast_unstake_events_since_last_call(),
-				// we slash them by 21, since we checked 3 eras in total (3, 2, 1).
 				vec![
 					Event::Checking { stash: exposed, eras: vec![3] },
 					Event::Checking { stash: exposed, eras: vec![2] },
-					Event::Slashed { stash: exposed, amount: 3 * 7 }
+					Event::Slashed { stash: exposed, amount: DepositAmount::get() }
 				]
 			);
 		});
@@ -721,7 +887,6 @@ mod on_idle {
 			// same as the previous check, but we check 2 eras per block, and we make the exposed be
 			// exposed in era 0, so that it is detected halfway in a check era.
 			ErasToCheckPerBlock::<T>::put(2);
-			SlashPerEra::set(7);
 			CurrentEra::<T>::put(BondingDuration::get());
 
 			// create an exposed nominator in era 1
@@ -729,7 +894,7 @@ mod on_idle {
 			pallet_staking::ErasStakers::<T>::mutate(0, VALIDATORS_PER_ERA, |expo| {
 				expo.others.push(IndividualExposure { who: exposed, value: 0 as Balance });
 			});
-			Balances::make_free_balance_be(&exposed, 100);
+			Balances::make_free_balance_be(&exposed, DepositAmount::get() + 100);
 			assert_ok!(Staking::bond(
 				RuntimeOrigin::signed(exposed),
 				exposed,
@@ -745,17 +910,21 @@ mod on_idle {
 			next_block(true);
 			assert_eq!(
 				Head::<T>::get(),
-				Some(UnstakeRequest { stash: exposed, checked: bounded_vec![3, 2] })
+				Some(UnstakeRequest {
+					deposit: DepositAmount::get(),
+					stash: exposed,
+					checked: bounded_vec![3, 2]
+				})
 			);
 			next_block(true);
 			assert_eq!(Head::<T>::get(), None);
 
 			assert_eq!(
 				fast_unstake_events_since_last_call(),
-				// we slash them by 28, since we checked 4 eras in total.
+				// we slash them
 				vec![
 					Event::Checking { stash: exposed, eras: vec![3, 2] },
-					Event::Slashed { stash: exposed, amount: 4 * 7 }
+					Event::Slashed { stash: exposed, amount: DepositAmount::get() }
 				]
 			);
 		});
@@ -786,7 +955,7 @@ mod on_idle {
 
 			assert_eq!(
 				fast_unstake_events_since_last_call(),
-				vec![Event::Slashed { stash: 100, amount: 100 }]
+				vec![Event::Slashed { stash: 100, amount: DepositAmount::get() }]
 			);
 		});
 	}
@@ -798,7 +967,7 @@ mod on_idle {
 			CurrentEra::<T>::put(BondingDuration::get());
 
 			// create a new validator that 100% not exposed.
-			Balances::make_free_balance_be(&42, 100);
+			Balances::make_free_balance_be(&42, 100 + DepositAmount::get());
 			assert_ok!(Staking::bond(RuntimeOrigin::signed(42), 42, 10, RewardDestination::Staked));
 			assert_ok!(Staking::validate(RuntimeOrigin::signed(42), Default::default()));
 
@@ -809,7 +978,11 @@ mod on_idle {
 			next_block(true);
 			assert_eq!(
 				Head::<T>::get(),
-				Some(UnstakeRequest { stash: 42, checked: bounded_vec![3, 2, 1, 0] })
+				Some(UnstakeRequest {
+					deposit: DepositAmount::get(),
+					stash: 42,
+					checked: bounded_vec![3, 2, 1, 0]
+				})
 			);
 			next_block(true);
 			assert_eq!(Head::<T>::get(), None);
@@ -824,69 +997,3 @@ mod on_idle {
 		});
 	}
 }
-
-mod signed_extension {
-	use super::*;
-	use sp_runtime::traits::SignedExtension;
-
-	const STAKING_CALL: crate::mock::RuntimeCall =
-		crate::mock::RuntimeCall::Staking(pallet_staking::Call::<T>::chill {});
-
-	#[test]
-	fn does_nothing_if_not_queued() {
-		ExtBuilder::default().build_and_execute(|| {
-			assert!(PreventStakingOpsIfUnbonding::<T>::new()
-				.pre_dispatch(&1, &STAKING_CALL, &Default::default(), Default::default())
-				.is_ok());
-		})
-	}
-
-	#[test]
-	fn prevents_queued() {
-		ExtBuilder::default().build_and_execute(|| {
-			// given: stash for 2 is 1.
-			// when
-			assert_ok!(FastUnstake::register_fast_unstake(RuntimeOrigin::signed(2)));
-
-			// then
-			// stash can't.
-			assert!(PreventStakingOpsIfUnbonding::<T>::new()
-				.pre_dispatch(&1, &STAKING_CALL, &Default::default(), Default::default())
-				.is_err());
-
-			// controller can't.
-			assert!(PreventStakingOpsIfUnbonding::<T>::new()
-				.pre_dispatch(&2, &STAKING_CALL, &Default::default(), Default::default())
-				.is_err());
-		})
-	}
-
-	#[test]
-	fn prevents_head_stash() {
-		ExtBuilder::default().build_and_execute(|| {
-			// given: stash for 2 is 1.
-			// when
-			assert_ok!(FastUnstake::register_fast_unstake(RuntimeOrigin::signed(2)));
-
-			ErasToCheckPerBlock::<T>::put(1);
-			CurrentEra::<T>::put(BondingDuration::get());
-			next_block(true);
-
-			assert_eq!(
-				Head::<T>::get(),
-				Some(UnstakeRequest { stash: 1, checked: bounded_vec![3] })
-			);
-
-			// then
-			// stash can't
-			assert!(PreventStakingOpsIfUnbonding::<T>::new()
-				.pre_dispatch(&2, &STAKING_CALL, &Default::default(), Default::default())
-				.is_err());
-
-			// controller can't
-			assert!(PreventStakingOpsIfUnbonding::<T>::new()
-				.pre_dispatch(&1, &STAKING_CALL, &Default::default(), Default::default())
-				.is_err());
-		})
-	}
-}

substrate/frame/fast-unstake/src/types.rs

@@ -17,14 +17,12 @@
 
 //! Types used in the Fast Unstake pallet.
 
-use crate::*;
 use codec::{Decode, Encode, MaxEncodedLen};
 use frame_support::{
-	traits::{Currency, Get, IsSubType},
+	traits::{Currency, Get},
 	BoundedVec, EqNoBound, PartialEqNoBound, RuntimeDebugNoBound,
 };
 use scale_info::TypeInfo;
-use sp_runtime::transaction_validity::{InvalidTransaction, TransactionValidityError};
 use sp_staking::EraIndex;
 use sp_std::{fmt::Debug, prelude::*};
 
@@ -36,80 +34,15 @@ pub type BalanceOf<T> = <<T as pallet_staking::Config>::Currency as Currency<
 #[derive(
 	Encode, Decode, EqNoBound, PartialEqNoBound, Clone, TypeInfo, RuntimeDebugNoBound, MaxEncodedLen,
 )]
-pub struct UnstakeRequest<AccountId: Eq + PartialEq + Debug, MaxChecked: Get<u32>> {
+pub struct UnstakeRequest<
+	AccountId: Eq + PartialEq + Debug,
+	MaxChecked: Get<u32>,
+	Balance: PartialEq + Debug,
+> {
 	/// Their stash account.
 	pub(crate) stash: AccountId,
 	/// The list of eras for which they have been checked.
 	pub(crate) checked: BoundedVec<EraIndex, MaxChecked>,
-}
-
-#[derive(Encode, Decode, Clone, Eq, PartialEq, TypeInfo, RuntimeDebugNoBound)]
-#[scale_info(skip_type_params(T))]
-pub struct PreventStakingOpsIfUnbonding<T: Config + Send + Sync>(sp_std::marker::PhantomData<T>);
-
-impl<T: Config + Send + Sync> PreventStakingOpsIfUnbonding<T> {
-	pub fn new() -> Self {
-		Self(Default::default())
-	}
-}
-
-impl<T: Config + Send + Sync> sp_runtime::traits::SignedExtension
-	for PreventStakingOpsIfUnbonding<T>
-where
-	<T as frame_system::Config>::RuntimeCall: IsSubType<pallet_staking::Call<T>>,
-{
-	type AccountId = T::AccountId;
-	type Call = <T as frame_system::Config>::RuntimeCall;
-	type AdditionalSigned = ();
-	type Pre = ();
-	const IDENTIFIER: &'static str = "PreventStakingOpsIfUnbonding";
-
-	fn additional_signed(&self) -> Result<Self::AdditionalSigned, TransactionValidityError> {
-		Ok(())
-	}
-
-	fn pre_dispatch(
-		self,
-		// NOTE: we want to prevent this stash-controller pair from doing anything in the
-		// staking system as long as they are registered here.
-		stash_or_controller: &Self::AccountId,
-		call: &Self::Call,
-		_info: &sp_runtime::traits::DispatchInfoOf<Self::Call>,
-		_len: usize,
-	) -> Result<Self::Pre, TransactionValidityError> {
-		// we don't check this in the tx-pool as it requires a storage read.
-		if <Self::Call as IsSubType<pallet_staking::Call<T>>>::is_sub_type(call).is_some() {
-			let check_stash = |stash: &T::AccountId| {
-				if Queue::<T>::contains_key(&stash) ||
-					Head::<T>::get().map_or(false, |u| &u.stash == stash)
-				{
-					Err(TransactionValidityError::Invalid(InvalidTransaction::Call))
-				} else {
-					Ok(())
-				}
-			};
-			match (
-				// mapped from controller.
-				pallet_staking::Ledger::<T>::get(&stash_or_controller),
-				// mapped from stash.
-				pallet_staking::Bonded::<T>::get(&stash_or_controller),
-			) {
-				(Some(ledger), None) => {
-					// it is a controller.
-					check_stash(&ledger.stash)
-				},
-				(_, Some(_)) => {
-					// it's a stash.
-					let stash = stash_or_controller;
-					check_stash(stash)
-				},
-				(None, None) => {
-					// They are not a staker -- let them execute.
-					Ok(())
-				},
-			}
-		} else {
-			Ok(())
-		}
-	}
+	/// Deposit to be slashed if the unstake was unsuccessful.
+	pub(crate) deposit: Balance,
 }