[Staking] Move reward minting to DAP; payouts from drip-funded era pots

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

@@ -1767,6 +1767,35 @@ parameter_types! {
 	);
 }
 
+/// Provides the initial `LastIssuanceTimestamp` for DAP migration.
+pub struct DapLastIssuanceTimestamp;
+impl frame_support::traits::Get<u64> for DapLastIssuanceTimestamp {
+	fn get() -> u64 {
+		pallet_staking_async::ActiveEra::<Runtime>::get()
+			.and_then(|era| era.start)
+			.unwrap_or(0)
+	}
+}
+
+/// Default budget: 85% staker rewards, 15% buffer.
+pub struct DefaultDapBudget;
+impl frame_support::traits::Get<pallet_dap::BudgetAllocationMap> for DefaultDapBudget {
+	fn get() -> pallet_dap::BudgetAllocationMap {
+		use sp_runtime::Perbill;
+		use sp_staking::budget::BudgetRecipientList;
+
+		let recipients = <Runtime as pallet_dap::Config>::BudgetRecipients::recipients();
+		// [dap (buffer), StakerRewardRecipient]
+		let percentages = [Perbill::from_percent(15), Perbill::from_percent(85)];
+
+		let mut map = pallet_dap::BudgetAllocationMap::new();
+		for ((key, _), perbill) in recipients.into_iter().zip(percentages) {
+			let _ = map.try_insert(key, perbill);
+		}
+		map
+	}
+}
+
 /// Migrations to apply on runtime upgrade.
 pub type Migrations = (
 	// v9420
@@ -1806,8 +1835,10 @@ pub type Migrations = (
 	// permanent
 	pallet_xcm::migration::MigrateToLatestXcmVersion<Runtime>,
 	cumulus_pallet_aura_ext::migration::MigrateV0ToV1<Runtime>,
+	// unreleased
 	// PSM: initialize first external asset (USDT) with fees and ceiling weight.
 	pallet_psm::migrations::v1::MigrateToV1<Runtime, PsmInitialConfig>,
+	pallet_dap::migrations::MigrateV1ToV2<Runtime, DapLastIssuanceTimestamp, DefaultDapBudget>,
 );
 
 /// Asset Hub Westend has some undecodable storage, delete it.
@@ -2011,6 +2042,7 @@ mod benches {
 		[pallet_bags_list, VoterList]
 		[pallet_balances, Balances]
 		[pallet_conviction_voting, ConvictionVoting]
+		[pallet_dap, Dap]
 		[pallet_election_provider_multi_block, MultiBlockElection]
 		[pallet_election_provider_multi_block::verifier, MultiBlockElectionVerifier]
 		[pallet_election_provider_multi_block::unsigned, MultiBlockElectionUnsigned]

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

@@ -228,29 +228,28 @@ impl pallet_bags_list::Config<VoterBagsListInstance> for Runtime {
 	type WeightInfo = weights::pallet_bags_list::WeightInfo<Runtime>;
 }
 
-pub struct EraPayout;
-impl pallet_staking_async::EraPayout<Balance> for EraPayout {
-	fn era_payout(
-		_total_staked: Balance,
-		_total_issuance: Balance,
-		era_duration_millis: u64,
-	) -> (Balance, Balance) {
+parameter_types! {
+	pub const StakingPotsPalletId: PalletId = PalletId(*b"py/stkng");
+}
+
+/// Westend inflation curve for DAP.
+///
+/// Same computation as the previous `EraPayout` but returns total emission.
+/// The budget split (ex. 85/15 staker/treasury) is now handled by pallet-dap.
+pub struct IssuanceCurve;
+impl sp_staking::budget::IssuanceCurve<Balance> for IssuanceCurve {
+	fn issue(_total_issuance: Balance, elapsed_millis: u64) -> Balance {
 		const MILLISECONDS_PER_YEAR: u64 = (1000 * 3600 * 24 * 36525) / 100;
-		// A normal-sized era will have 1 / 365.25 here:
-		let relative_era_len =
-			FixedU128::from_rational(era_duration_millis.into(), MILLISECONDS_PER_YEAR.into());
+		let relative_period =
+			FixedU128::from_rational(elapsed_millis.into(), MILLISECONDS_PER_YEAR.into());
 
 		// Fixed total TI that we use as baseline for the issuance.
 		let fixed_total_issuance: i128 = 5_216_342_402_773_185_773;
 		let fixed_inflation_rate = FixedU128::from_rational(8, 100);
 		let yearly_emission = fixed_inflation_rate.saturating_mul_int(fixed_total_issuance);
 
-		let era_emission = relative_era_len.saturating_mul_int(yearly_emission);
-		// 15% to treasury, as per Polkadot ref 1139.
-		let to_treasury = FixedU128::from_rational(15, 100).saturating_mul_int(era_emission);
-		let to_stakers = era_emission.saturating_sub(to_treasury);
-
-		(to_stakers.saturated_into(), to_treasury.saturated_into())
+		let emission = relative_period.saturating_mul_int(yearly_emission);
+		emission.saturated_into()
 	}
 }
 
@@ -287,7 +286,7 @@ impl pallet_staking_async::Config for Runtime {
 	type NominatorFastUnbondDuration = NominatorFastUnbondDuration;
 	type SlashDeferDuration = SlashDeferDuration;
 	type AdminOrigin = EitherOf<EnsureRoot<AccountId>, StakingAdmin>;
-	type EraPayout = EraPayout;
+	type EraPayout = ();
 	type MaxExposurePageSize = MaxExposurePageSize;
 	type ElectionProvider = MultiBlockElection;
 	type VoterList = VoterList;
@@ -301,6 +300,11 @@ impl pallet_staking_async::Config for Runtime {
 	type PlanningEraOffset = ConstU32<6>;
 	type RcClientInterface = StakingRcClient;
 	type MaxEraDuration = MaxEraDuration;
+	type DisableMinting = ConstBool<true>;
+	type UnclaimedRewardHandler = Dap;
+	type RewardPots = pallet_staking_async::Seed<StakingPotsPalletId>;
+	type StakerRewardCalculator =
+		pallet_staking_async::reward::DefaultStakerRewardCalculator<Runtime>;
 	type MaxPruningItems = MaxPruningItems;
 	type WeightInfo = weights::pallet_staking_async::WeightInfo<Runtime>;
 }
@@ -353,9 +357,13 @@ parameter_types! {
 impl pallet_dap::Config for Runtime {
 	type Currency = Balances;
 	type PalletId = DapPalletId;
-	/// Noop — DAP does not mint until budget drip is enabled.
-	type IssuanceCurve = ();
-	type BudgetRecipients = (pallet_dap::Pallet<Runtime>,);
+	type IssuanceCurve = IssuanceCurve;
+	type BudgetRecipients = (
+		pallet_dap::Pallet<Runtime>,
+		pallet_staking_async::StakerRewardRecipient<
+			pallet_staking_async::Seed<StakingPotsPalletId>,
+		>,
+	);
 	type Time = pallet_timestamp::Pallet<Runtime>;
 	type IssuanceCadence = IssuanceCadence;
 	type MaxElapsedPerDrip = MaxElapsedPerDrip;

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

@@ -0,0 +1,82 @@
+// Copyright (C) Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: Apache-2.0
+
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// 	http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//! Autogenerated weights for `pallet_dap`
+//!
+//! THIS FILE WAS AUTO-GENERATED USING THE SUBSTRATE BENCHMARK CLI VERSION 32.0.0
+//! DATE: 2026-04-03, STEPS: `50`, REPEAT: `20`, LOW RANGE: `[]`, HIGH RANGE: `[]`
+//! WORST CASE MAP SIZE: `1000000`
+//! HOSTNAME: `5851f50484f3`, CPU: `Intel(R) Xeon(R) CPU @ 2.60GHz`
+//! WASM-EXECUTION: `Compiled`, CHAIN: `None`, DB CACHE: 1024
+
+// Executed Command:
+// frame-omni-bencher
+// v1
+// benchmark
+// pallet
+// --extrinsic=*
+// --runtime=target/production/wbuild/asset-hub-westend-runtime/asset_hub_westend_runtime.wasm
+// --pallet=pallet_dap
+// --header=/__w/polkadot-sdk/polkadot-sdk/cumulus/file_header.txt
+// --output=./cumulus/parachains/runtimes/assets/asset-hub-westend/src/weights
+// --wasm-execution=compiled
+// --steps=50
+// --repeat=20
+// --heap-pages=4096
+// --no-storage-info
+// --no-min-squares
+// --no-median-slopes
+
+#![cfg_attr(rustfmt, rustfmt_skip)]
+#![allow(unused_parens)]
+#![allow(unused_imports)]
+#![allow(missing_docs)]
+
+use frame_support::{traits::Get, weights::Weight};
+use core::marker::PhantomData;
+
+/// Weight functions for `pallet_dap`.
+pub struct WeightInfo<T>(PhantomData<T>);
+impl<T: frame_system::Config> pallet_dap::WeightInfo for WeightInfo<T> {
+	/// Storage: `Dap::BudgetAllocation` (r:0 w:1)
+	/// Proof: `Dap::BudgetAllocation` (`max_values`: Some(1), `max_size`: Some(593), added: 1088, mode: `MaxEncodedLen`)
+	fn set_budget_allocation() -> Weight {
+		// Proof Size summary in bytes:
+		//  Measured:  `0`
+		//  Estimated: `0`
+		// Minimum execution time: 7_979_000 picoseconds.
+		Weight::from_parts(8_699_000, 0)
+			.saturating_add(Weight::from_parts(0, 0))
+			.saturating_add(T::DbWeight::get().writes(1))
+	}
+	/// Storage: `Timestamp::Now` (r:1 w:0)
+	/// Proof: `Timestamp::Now` (`max_values`: Some(1), `max_size`: Some(8), added: 503, mode: `MaxEncodedLen`)
+	/// Storage: `Dap::LastIssuanceTimestamp` (r:1 w:1)
+	/// Proof: `Dap::LastIssuanceTimestamp` (`max_values`: Some(1), `max_size`: Some(8), added: 503, mode: `MaxEncodedLen`)
+	/// Storage: `Dap::BudgetAllocation` (r:1 w:0)
+	/// Proof: `Dap::BudgetAllocation` (`max_values`: Some(1), `max_size`: Some(593), added: 1088, mode: `MaxEncodedLen`)
+	/// Storage: `System::Account` (r:2 w:2)
+	/// Proof: `System::Account` (`max_values`: None, `max_size`: Some(128), added: 2603, mode: `MaxEncodedLen`)
+	fn drip_issuance() -> Weight {
+		// Proof Size summary in bytes:
+		//  Measured:  `2541`
+		//  Estimated: `6196`
+		// Minimum execution time: 62_672_000 picoseconds.
+		Weight::from_parts(65_724_000, 0)
+			.saturating_add(Weight::from_parts(0, 6196))
+			.saturating_add(T::DbWeight::get().reads(5))
+			.saturating_add(T::DbWeight::get().writes(3))
+	}
+}