fix existential deposit with block-rewards (#1802)

pallets/block-rewards/src/lib.rs

@@ -50,7 +50,7 @@ use frame_support::{
 	storage::transactional,
 	traits::{
 		fungible::{Inspect as FungibleInspect, Mutate as FungibleMutate},
-		fungibles::Mutate,
+		fungibles::{Inspect, Mutate},
 		tokens::{Balance, Fortitude, Precision},
 		OneSessionHandler,
 	},
@@ -132,9 +132,6 @@ pub mod pallet {
 		/// Type used to handle balances.
 		type Balance: Balance + MaxEncodedLen + FixedPointOperand + MaybeSerializeDeserialize;
 
-		#[pallet::constant]
-		type ExistentialDeposit: Get<Self::Balance>;
-
 		/// Type used to handle group weights.
 		type Weight: Parameter + MaxEncodedLen + EnsureAdd + Unsigned + FixedPointOperand + Default;
 
@@ -147,8 +144,12 @@ pub mod pallet {
 			> + CurrencyGroupChange<GroupId = u32, CurrencyId = <Self as Config>::CurrencyId>;
 
 		/// The type used to handle currency minting and burning for collators.
-		type Tokens: Mutate<Self::AccountId, AssetId = <Self as Config>::CurrencyId, Balance = Self::Balance>
-			+ FungibleMutate<Self::AccountId>
+		type Tokens: Mutate<Self::AccountId>
+			+ Inspect<
+				Self::AccountId,
+				AssetId = <Self as Config>::CurrencyId,
+				Balance = Self::Balance,
+			> + FungibleMutate<Self::AccountId>
 			+ FungibleInspect<Self::AccountId, Balance = Self::Balance>;
 
 		/// The currency type of the artificial block rewards currency.
@@ -314,10 +315,13 @@ impl<T: Config> Pallet<T> {
 	///  * deposit_stake (4 reads, 4 writes): Currency, Group, StakeAccount,
 	///    Account
 	pub(crate) fn do_init_collator(who: &T::AccountId) -> DispatchResult {
+		let existential_deposit =
+			<T::Tokens as Inspect<T::AccountId>>::minimum_balance(T::StakeCurrencyId::get());
+
 		<T::Tokens as Mutate<T::AccountId>>::mint_into(
 			T::StakeCurrencyId::get(),
 			who,
-			T::StakeAmount::get().saturating_add(T::ExistentialDeposit::get()),
+			T::StakeAmount::get().saturating_add(existential_deposit),
 		)?;
 		T::Rewards::deposit_stake(T::StakeCurrencyId::get(), who, T::StakeAmount::get())
 	}

pallets/block-rewards/src/mock.rs

@@ -5,7 +5,10 @@ use cfg_types::{
 };
 use frame_support::{
 	derive_impl, parameter_types,
-	traits::{fungibles::Inspect, tokens::WithdrawConsequence, ConstU32, OnFinalize, OnInitialize},
+	traits::{
+		fungibles::Inspect, tokens::WithdrawConsequence, ConstU128, ConstU32, OnFinalize,
+		OnInitialize,
+	},
 	PalletId,
 };
 use frame_system::EnsureRoot;
@@ -81,26 +84,24 @@ impl pallet_session::Config for Test {
 	type WeightInfo = ();
 }
 
-parameter_types! {
-	// the minimum fee for an anchor is 500,000ths of a CFG.
-	// This is set to a value so you can still get some return without getting your account removed.
-	pub const ExistentialDeposit: Balance = 1 * cfg_primitives::MICRO_CFG;
-}
+pub const BALANCE_ED: Balance = 23;
+pub const REWARD_CURRENCY_ED: Balance = 42;
 
 #[derive_impl(pallet_balances::config_preludes::TestDefaultConfig as pallet_balances::DefaultConfig)]
 impl pallet_balances::Config for Test {
 	type AccountStore = System;
 	type Balance = Balance;
 	type DustRemoval = ();
-	type ExistentialDeposit = ExistentialDeposit;
+	type ExistentialDeposit = ConstU128<BALANCE_ED>;
 	type RuntimeHoldReason = ();
 }
 
 orml_traits::parameter_type_with_key! {
 	pub ExistentialDeposits: |currency_id: CurrencyId| -> Balance {
 		match currency_id {
-			CurrencyId::Native => ExistentialDeposit::get(),
-			_ => 1,
+			CurrencyId::Native => BALANCE_ED,
+			CurrencyId::Staking(BlockRewardsCurrency) => REWARD_CURRENCY_ED,
+			_ => unreachable!()
 		}
 	};
 }
@@ -188,7 +189,6 @@ impl pallet_block_rewards::Config for Test {
 	type AuthorityId = UintAuthorityId;
 	type Balance = Balance;
 	type CurrencyId = CurrencyId;
-	type ExistentialDeposit = ExistentialDeposit;
 	type MaxCollators = MaxCollators;
 	type Rate = Rate;
 	type Rewards = Rewards;
@@ -207,13 +207,13 @@ pub(crate) fn assert_staked(who: &AccountId) {
 	assert_eq!(
 		// NOTE: This is now the ED instead of 0, as we collators need ED now.
 		Tokens::balance(BlockRewardCurrency::get(), who),
-		ExistentialDeposit::get()
+		REWARD_CURRENCY_ED
 	);
 	assert_eq!(
 		<Test as Config>::Tokens::can_withdraw(
 			<Test as Config>::StakeCurrencyId::get(),
 			who,
-			ExistentialDeposit::get() * 2
+			REWARD_CURRENCY_ED * 2
 		),
 		WithdrawConsequence::BalanceLow
 	);
@@ -229,11 +229,7 @@ pub(crate) fn assert_not_staked(who: &AccountId, was_before: bool) {
 		<Test as Config>::Tokens::balance(<Test as Config>::StakeCurrencyId::get(), who),
 		// NOTE: IF a collator has been staked before the system already granted them ED
 		//       of `StakeCurrency`.
-		if was_before {
-			ExistentialDeposit::get()
-		} else {
-			0
-		}
+		if was_before { REWARD_CURRENCY_ED } else { 0 }
 	);
 }
 

pallets/block-rewards/src/tests.rs

@@ -1,4 +1,4 @@
-use cfg_primitives::{CFG, SECONDS_PER_YEAR};
+use cfg_primitives::SECONDS_PER_YEAR;
 use cfg_types::{
 	fixed_point::Rate,
 	tokens::{CurrencyId, StakingCurrency},
@@ -13,7 +13,7 @@ use crate::mock::*;
 // The Reward amount
 // NOTE: This value needs to be > ExistentialDeposit, otherwise the tests will
 // fail as it's not allowed to transfer a value below the ED threshold.
-const REWARD: u128 = 100 * CFG + ExistentialDeposit::get();
+const REWARD: u128 = 100 * BALANCE_ED;
 
 #[test]
 fn check_special_privileges() {
@@ -105,7 +105,7 @@ fn joining_leaving_collators() {
 			<Tokens as fungibles::Inspect<AccountId>>::total_issuance(CurrencyId::Staking(
 				StakingCurrency::BlockRewards
 			)),
-			<Test as Config>::StakeAmount::get() as u128 + ExistentialDeposit::get()
+			<Test as Config>::StakeAmount::get() as u128 + REWARD_CURRENCY_ED
 		);
 
 		advance_session();
@@ -126,7 +126,7 @@ fn joining_leaving_collators() {
 			<Tokens as fungibles::Inspect::<AccountId>>::total_issuance(CurrencyId::Staking(
 				StakingCurrency::BlockRewards
 			)),
-			<Test as Config>::StakeAmount::get() as u128 + ExistentialDeposit::get()
+			<Test as Config>::StakeAmount::get() as u128 + REWARD_CURRENCY_ED
 		);
 
 		advance_session();
@@ -149,7 +149,7 @@ fn joining_leaving_collators() {
 			<Tokens as fungibles::Inspect::<AccountId>>::total_issuance(CurrencyId::Staking(
 				StakingCurrency::BlockRewards
 			)),
-			2 * <Test as Config>::StakeAmount::get() as u128 + 3 * ExistentialDeposit::get()
+			2 * <Test as Config>::StakeAmount::get() as u128 + 3 * REWARD_CURRENCY_ED
 		);
 
 		advance_session();
@@ -173,7 +173,7 @@ fn joining_leaving_collators() {
 			<Tokens as fungibles::Inspect::<AccountId>>::total_issuance(CurrencyId::Staking(
 				StakingCurrency::BlockRewards
 			)),
-			3 * <Test as Config>::StakeAmount::get() as u128 + 5 * ExistentialDeposit::get()
+			3 * <Test as Config>::StakeAmount::get() as u128 + 5 * REWARD_CURRENCY_ED
 		);
 	});
 }
@@ -223,10 +223,7 @@ fn single_claim_reward() {
 				Balances::total_balance(&TreasuryPalletId::get().into_account_truncating()),
 				0
 			);
-			assert_eq!(
-				Balances::total_issuance(),
-				REWARD + ExistentialDeposit::get()
-			);
+			assert_eq!(Balances::total_issuance(), REWARD + BALANCE_ED);
 			assert_eq!(Balances::free_balance(&1), REWARD);
 		});
 }
@@ -244,7 +241,7 @@ fn collator_rewards_greater_than_remainder() {
 				Balances::free_balance(&TreasuryPalletId::get().into_account_truncating());
 
 			// EPOCH 0 -> EPOCH
-			let total_issuance = ExistentialDeposit::get();
+			let total_issuance = BALANCE_ED;
 			assert_eq!(Balances::total_issuance(), total_issuance);
 			MockTime::mock_now(|| SECONDS_PER_YEAR * 1000);
 			advance_session();

runtime/altair/src/lib.rs

@@ -1240,7 +1240,6 @@ impl pallet_block_rewards::Config for Runtime {
 	type AuthorityId = AuraId;
 	type Balance = Balance;
 	type CurrencyId = CurrencyId;
-	type ExistentialDeposit = ExistentialDeposit;
 	type MaxCollators = MaxAuthorities;
 	type Rate = Rate;
 	type Rewards = BlockRewardsBase;

runtime/centrifuge/src/lib.rs

@@ -1254,7 +1254,6 @@ impl pallet_block_rewards::Config for Runtime {
 	type AuthorityId = AuraId;
 	type Balance = Balance;
 	type CurrencyId = CurrencyId;
-	type ExistentialDeposit = ExistentialDeposit;
 	type MaxCollators = MaxAuthorities;
 	type Rate = Rate;
 	type Rewards = BlockRewardsBase;

runtime/common/src/lib.rs

@@ -28,7 +28,11 @@ pub mod transfer_filter;
 pub mod xcm;
 
 use cfg_primitives::Balance;
-use cfg_types::{fee_keys::FeeKey, pools::PoolNav, tokens::CurrencyId};
+use cfg_types::{
+	fee_keys::FeeKey,
+	pools::PoolNav,
+	tokens::{CurrencyId, StakingCurrency},
+};
 use orml_traits::GetByKey;
 use pallet_loans::entities::input::PriceCollectionInput;
 use pallet_pool_system::Nav;
@@ -81,6 +85,7 @@ where
 	fn get(currency_id: &CurrencyId) -> Balance {
 		match currency_id {
 			CurrencyId::Native => T::ExistentialDeposit::get(),
+			CurrencyId::Staking(StakingCurrency::BlockRewards) => T::ExistentialDeposit::get(),
 			currency_id => orml_asset_registry::Pallet::<T>::metadata(currency_id)
 				.map(|metadata| metadata.existential_deposit)
 				.unwrap_or_default(),

runtime/development/src/lib.rs

@@ -1247,7 +1247,7 @@ type CollatorSelectionUpdateOrigin = EitherOfDiverse<
 
 // Implement Collator Selection pallet configuration trait for the runtime
 impl pallet_collator_selection::Config for Runtime {
-	type Currency = Tokens;
+	type Currency = Balances;
 	// should be a multiple of session or things will get inconsistent
 	type KickThreshold = Period;
 	type MaxCandidates = MaxCandidates;
@@ -1738,7 +1738,6 @@ impl pallet_block_rewards::Config for Runtime {
 	type AuthorityId = AuraId;
 	type Balance = Balance;
 	type CurrencyId = CurrencyId;
-	type ExistentialDeposit = ExistentialDeposit;
 	type MaxCollators = MaxAuthorities;
 	type Rate = Rate;
 	type Rewards = BlockRewardsBase;