frame/transaction-storage: replace Currency with fungible traits

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

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

@@ -1820,6 +1820,7 @@ impl pallet_nfts::Config for Runtime {
 impl pallet_transaction_storage::Config for Runtime {
 	type RuntimeEvent = RuntimeEvent;
 	type Currency = Balances;
+	type RuntimeHoldReason = RuntimeHoldReason;
 	type RuntimeCall = RuntimeCall;
 	type FeeDestination = ();
 	type WeightInfo = pallet_transaction_storage::weights::SubstrateWeight<Runtime>;

substrate/frame/transaction-storage/src/lib.rs

@@ -31,7 +31,13 @@ mod tests;
 use codec::{Decode, Encode, MaxEncodedLen};
 use frame_support::{
 	dispatch::GetDispatchInfo,
-	traits::{Currency, OnUnbalanced, ReservableCurrency},
+	traits::{
+		fungible::{
+			hold::Balanced as FnBalanced, Inspect as FnInspect, MutateHold as FnMutateHold,
+		},
+		tokens::fungible::Credit,
+		OnUnbalanced,
+	},
 };
 use sp_runtime::traits::{BlakeTwo256, Dispatchable, Hash, One, Saturating, Zero};
 use sp_std::{prelude::*, result};
@@ -42,10 +48,8 @@ use sp_transaction_storage_proof::{
 
 /// A type alias for the balance type from this pallet's point of view.
 type BalanceOf<T> =
-	<<T as Config>::Currency as Currency<<T as frame_system::Config>::AccountId>>::Balance;
-type NegativeImbalanceOf<T> = <<T as Config>::Currency as Currency<
-	<T as frame_system::Config>::AccountId,
->>::NegativeImbalance;
+	<<T as Config>::Currency as FnInspect<<T as frame_system::Config>::AccountId>>::Balance;
+pub type CreditOf<T> = Credit<<T as frame_system::Config>::AccountId, <T as Config>::Currency>;
 
 // Re-export pallet items so that they can be accessed from the crate namespace.
 pub use pallet::*;
@@ -89,6 +93,13 @@ pub mod pallet {
 	use frame_support::pallet_prelude::*;
 	use frame_system::pallet_prelude::*;
 
+	/// A reason for this pallet placing a hold on funds.
+	#[pallet::composite_enum]
+	pub enum HoldReason {
+		/// The funds are held as deposit for the used storage.
+		StorageFeeHold,
+	}
+
 	#[pallet::config]
 	pub trait Config: frame_system::Config {
 		/// The overarching event type.
@@ -98,10 +109,13 @@ pub mod pallet {
 			+ Dispatchable<RuntimeOrigin = Self::RuntimeOrigin>
 			+ GetDispatchInfo
 			+ From<frame_system::Call<Self>>;
-		/// The currency trait.
-		type Currency: ReservableCurrency<Self::AccountId>;
+		/// The currency type for this pallet.
+		type Currency: FnMutateHold<Self::AccountId, Reason = Self::RuntimeHoldReason>
+			+ FnBalanced<Self::AccountId>;
+		/// The overarching runtime hold reason.
+		type RuntimeHoldReason: From<HoldReason>;
 		/// Handler for the unbalanced decrease when fees are burned.
-		type FeeDestination: OnUnbalanced<NegativeImbalanceOf<Self>>;
+		type FeeDestination: OnUnbalanced<CreditOf<Self>>;
 		/// Weight information for extrinsics in this pallet.
 		type WeightInfo: WeightInfo;
 		/// Maximum number of indexed transactions in the block.
@@ -112,8 +126,6 @@ pub mod pallet {
 
 	#[pallet::error]
 	pub enum Error<T> {
-		/// Insufficient account balance.
-		InsufficientFunds,
 		/// Invalid configuration.
 		NotConfigured,
 		/// Renewed extrinsic is not found.
@@ -432,8 +444,8 @@ pub mod pallet {
 			let byte_fee = ByteFee::<T>::get().ok_or(Error::<T>::NotConfigured)?;
 			let entry_fee = EntryFee::<T>::get().ok_or(Error::<T>::NotConfigured)?;
 			let fee = byte_fee.saturating_mul(size.into()).saturating_add(entry_fee);
-			ensure!(T::Currency::can_slash(&sender, fee), Error::<T>::InsufficientFunds);
-			let (credit, _) = T::Currency::slash(&sender, fee);
+			T::Currency::hold(&HoldReason::StorageFeeHold.into(), &sender, fee)?;
+			let (credit, _) = T::Currency::slash(&HoldReason::StorageFeeHold.into(), &sender, fee);
 			T::FeeDestination::on_unbalanced(credit);
 			Ok(())
 		}

substrate/frame/transaction-storage/src/mock.rs

@@ -18,10 +18,13 @@
 //! Test environment for transaction-storage pallet.
 
 use crate::{
-	self as pallet_transaction_storage, TransactionStorageProof, DEFAULT_MAX_BLOCK_TRANSACTIONS,
-	DEFAULT_MAX_TRANSACTION_SIZE,
+	self as pallet_transaction_storage, HoldReason, TransactionStorageProof,
+	DEFAULT_MAX_BLOCK_TRANSACTIONS, DEFAULT_MAX_TRANSACTION_SIZE,
+};
+use frame_support::{
+	derive_impl,
+	traits::{ConstU16, ConstU32, ConstU64, OnFinalize, OnInitialize},
 };
-use frame_support::traits::{ConstU16, ConstU32, ConstU64, OnFinalize, OnInitialize};
 use sp_core::H256;
 use sp_runtime::{
 	traits::{BlakeTwo256, IdentityLookup},
@@ -68,26 +71,20 @@ impl frame_system::Config for Test {
 	type MaxConsumers = ConstU32<16>;
 }
 
+#[derive_impl(pallet_balances::config_preludes::TestDefaultConfig as pallet_balances::DefaultConfig)]
 impl pallet_balances::Config for Test {
 	type Balance = u64;
-	type DustRemoval = ();
-	type RuntimeEvent = RuntimeEvent;
 	type ExistentialDeposit = ConstU64<1>;
 	type AccountStore = System;
-	type WeightInfo = ();
-	type MaxLocks = ();
-	type MaxReserves = ();
-	type ReserveIdentifier = ();
-	type FreezeIdentifier = ();
-	type MaxFreezes = ();
-	type RuntimeHoldReason = ();
-	type MaxHolds = ();
+	type RuntimeHoldReason = HoldReason;
+	type MaxHolds = ConstU32<128>;
 }
 
 impl pallet_transaction_storage::Config for Test {
 	type RuntimeEvent = RuntimeEvent;
 	type RuntimeCall = RuntimeCall;
 	type Currency = Balances;
+	type RuntimeHoldReason = HoldReason;
 	type FeeDestination = ();
 	type WeightInfo = ();
 	type MaxBlockTransactions = ConstU32<{ DEFAULT_MAX_BLOCK_TRANSACTIONS }>;

substrate/frame/transaction-storage/src/tests.rs

@@ -21,6 +21,7 @@ use super::{Pallet as TransactionStorage, *};
 use crate::mock::*;
 use frame_support::{assert_noop, assert_ok};
 use frame_system::RawOrigin;
+use sp_runtime::{DispatchError, TokenError::FundsUnavailable};
 use sp_transaction_storage_proof::registration::build_proof;
 
 const MAX_DATA_SIZE: u32 = DEFAULT_MAX_TRANSACTION_SIZE;
@@ -71,7 +72,7 @@ fn burns_fee() {
 				RawOrigin::Signed(5).into(),
 				vec![0u8; 2000 as usize]
 			),
-			Error::<Test>::InsufficientFunds,
+			DispatchError::Token(FundsUnavailable),
 		);
 		assert_ok!(TransactionStorage::<Test>::store(
 			RawOrigin::Signed(caller).into(),