staking: redirect slash to DAP for WAH and staking-async testnet

Author: sigurpol

Cargo.lock

@@ -120,6 +120,7 @@ cumulus-primitives-aura = { workspace = true }
 cumulus-primitives-core = { workspace = true }
 cumulus-primitives-utility = { workspace = true }
 pallet-collator-selection = { workspace = true }
+pallet-dap = { workspace = true }
 pallet-message-queue = { workspace = true }
 parachain-info = { workspace = true }
 parachains-common = { workspace = true }
@@ -173,6 +174,7 @@ runtime-benchmarks = [
 	"pallet-balances/runtime-benchmarks",
 	"pallet-collator-selection/runtime-benchmarks",
 	"pallet-conviction-voting/runtime-benchmarks",
+	"pallet-dap/runtime-benchmarks",
 	"pallet-delegated-staking/runtime-benchmarks",
 	"pallet-election-provider-multi-block/runtime-benchmarks",
 	"pallet-fast-unstake/runtime-benchmarks",
@@ -246,6 +248,7 @@ try-runtime = [
 	"pallet-balances/try-runtime",
 	"pallet-collator-selection/try-runtime",
 	"pallet-conviction-voting/try-runtime",
+	"pallet-dap/try-runtime",
 	"pallet-delegated-staking/try-runtime",
 	"pallet-election-provider-multi-block/try-runtime",
 	"pallet-fast-unstake/try-runtime",
@@ -326,6 +329,7 @@ std = [
 	"pallet-balances/std",
 	"pallet-collator-selection/std",
 	"pallet-conviction-voting/std",
+	"pallet-dap/std",
 	"pallet-delegated-staking/std",
 	"pallet-election-provider-multi-block/std",
 	"pallet-fast-unstake/std",

cumulus/parachains/runtimes/assets/asset-hub-westend/Cargo.toml

@@ -1397,6 +1397,9 @@ construct_runtime!(
 		Treasury: pallet_treasury = 94,
 		AssetRate: pallet_asset_rate = 95,
 
+		// Dynamic Allocation Pool / Issuance Buffer
+		Dap: pallet_dap = 100,
+
 		// TODO: the pallet instance should be removed once all pools have migrated
 		// to the new account IDs.
 		AssetConversionMigration: pallet_asset_conversion_ops = 200,

cumulus/parachains/runtimes/assets/asset-hub-westend/src/lib.rs

@@ -278,7 +278,7 @@ impl pallet_staking_async::Config for Runtime {
 	type RuntimeHoldReason = RuntimeHoldReason;
 	type CurrencyToVote = sp_staking::currency_to_vote::SaturatingCurrencyToVote;
 	type RewardRemainder = ();
-	type Slash = ();
+	type Slash = pallet_dap::SlashToDap<Runtime>;
 	type Reward = ();
 	type SessionsPerEra = SessionsPerEra;
 	type BondingDuration = BondingDuration;
@@ -311,6 +311,10 @@ impl pallet_staking_async_rc_client::Config for Runtime {
 	type ValidatorSetExportSession = ConstU32<4>;
 }
 
+impl pallet_dap::Config for Runtime {
+	type Currency = Balances;
+}
+
 #[derive(Encode, Decode)]
 // Call indices taken from westend-next runtime.
 pub enum RelayChainRuntimePallets {

cumulus/parachains/runtimes/assets/asset-hub-westend/src/staking.rs

@@ -32,8 +32,9 @@ extern crate alloc;
 use frame_support::{
 	pallet_prelude::*,
 	traits::{
-		fungible::{Inspect, Mutate},
+		fungible::{Balanced, Credit, Inspect, Mutate},
 		tokens::{FundingSink, FundingSource, Preservation},
+		Imbalance, OnUnbalanced,
 	},
 	PalletId,
 };
@@ -60,7 +61,9 @@ pub mod pallet {
 	#[pallet::config]
 	pub trait Config: frame_system::Config {
 		/// The currency type.
-		type Currency: Inspect<Self::AccountId> + Mutate<Self::AccountId>;
+		type Currency: Inspect<Self::AccountId>
+			+ Mutate<Self::AccountId>
+			+ Balanced<Self::AccountId>;
 	}
 
 	impl<T: Config> Pallet<T> {
@@ -118,6 +121,28 @@ impl<T: Config> FundingSink<T::AccountId, BalanceOf<T>> for ReturnToDap<T> {
 	}
 }
 
+/// Type alias for credit (negative imbalance - funds that were slashed/removed).
+pub type CreditOf<T> = Credit<<T as frame_system::Config>::AccountId, <T as Config>::Currency>;
+
+/// Implementation of OnUnbalanced that deposits slashed funds into the DAP buffer.
+/// Use this as `type Slash = SlashToDap<Runtime>` in staking config.
+pub struct SlashToDap<T>(core::marker::PhantomData<T>);
+
+impl<T: Config> OnUnbalanced<CreditOf<T>> for SlashToDap<T> {
+	fn on_nonzero_unbalanced(amount: CreditOf<T>) {
+		let buffer = Pallet::<T>::buffer_account();
+		let numeric_amount = amount.peek();
+
+		// Resolve the imbalance by depositing into the buffer account
+		let _ = T::Currency::resolve(&buffer, amount);
+
+		log::debug!(
+			target: LOG_TARGET,
+			"Deposited slash of {numeric_amount:?} to DAP buffer"
+		);
+	}
+}
+
 #[cfg(test)]
 mod tests {
 	use super::*;

substrate/frame/dap/src/lib.rs

@@ -42,6 +42,7 @@ frame-benchmarking = { workspace = true, default-features = true }
 frame-support = { features = ["experimental"], workspace = true, default-features = true }
 pallet-bags-list = { workspace = true, default-features = true }
 pallet-balances = { workspace = true, default-features = true }
+pallet-dap = { workspace = true, default-features = true }
 rand_chacha = { workspace = true, default-features = true }
 sp-tracing = { workspace = true, default-features = true }
 substrate-test-utils = { workspace = true }

substrate/frame/staking-async/Cargo.toml

@@ -52,6 +52,7 @@ frame_support::construct_runtime!(
 		Balances: pallet_balances,
 		Staking: pallet_staking_async,
 		VoterBagsList: pallet_bags_list::<Instance1>,
+		Dap: pallet_dap,
 	}
 );
 
@@ -110,6 +111,10 @@ impl pallet_balances::Config for Test {
 	type AccountStore = System;
 }
 
+impl pallet_dap::Config for Test {
+	type Currency = Balances;
+}
+
 parameter_types! {
 	pub static RewardRemainderUnbalanced: u128 = 0;
 }
@@ -454,7 +459,7 @@ impl crate::pallet::pallet::Config for Test {
 	type RcClientInterface = session_mock::Session;
 	type CurrencyBalance = Balance;
 	type CurrencyToVote = SaturatingCurrencyToVote;
-	type Slash = ();
+	type Slash = pallet_dap::SlashToDap<Test>;
 	type WeightInfo = ();
 }