westend-runtime: integrate with pallet-dap-satellite

Integrate westend-runtime with pallet-dap-satellite.
Preserve the pre-existing logic for which:
- 100% of tx fees -> block author
- 100% of tips -> block author

This is an overkill for Westend but is just an exercise in preparation
of what we will do for Polkadot and Kusama (e.g. X% / 100 -X% split)

Author: sigurpol

Cargo.lock

@@ -60,6 +60,7 @@ pallet-balances = { workspace = true }
 pallet-beefy = { workspace = true }
 pallet-beefy-mmr = { workspace = true }
 pallet-conviction-voting = { workspace = true }
+pallet-dap-satellite = { workspace = true }
 pallet-delegated-staking = { workspace = true }
 pallet-election-provider-multi-phase = { workspace = true }
 pallet-fast-unstake = { workspace = true }
@@ -156,6 +157,7 @@ std = [
 	"pallet-beefy-mmr/std",
 	"pallet-beefy/std",
 	"pallet-conviction-voting/std",
+	"pallet-dap-satellite/std",
 	"pallet-delegated-staking/std",
 	"pallet-election-provider-multi-phase/std",
 	"pallet-election-provider-support-benchmarking?/std",
@@ -246,6 +248,7 @@ runtime-benchmarks = [
 	"pallet-balances/runtime-benchmarks",
 	"pallet-beefy-mmr/runtime-benchmarks",
 	"pallet-conviction-voting/runtime-benchmarks",
+	"pallet-dap-satellite/runtime-benchmarks",
 	"pallet-delegated-staking/runtime-benchmarks",
 	"pallet-election-provider-multi-phase/runtime-benchmarks",
 	"pallet-election-provider-support-benchmarking/runtime-benchmarks",
@@ -312,6 +315,7 @@ try-runtime = [
 	"pallet-beefy-mmr/try-runtime",
 	"pallet-beefy/try-runtime",
 	"pallet-conviction-voting/try-runtime",
+	"pallet-dap-satellite/try-runtime",
 	"pallet-delegated-staking/try-runtime",
 	"pallet-election-provider-multi-phase/try-runtime",
 	"pallet-fast-unstake/try-runtime",

polkadot/runtime/westend/Cargo.toml

@@ -35,10 +35,11 @@ use frame_support::{
 	genesis_builder_helper::{build_state, get_preset},
 	parameter_types,
 	traits::{
-		fungible::HoldConsideration, tokens::UnityOrOuterConversion, AsEnsureOriginWithArg,
-		ConstU32, Contains, EitherOf, EitherOfDiverse, EnsureOriginWithArg, FromContains,
-		InstanceFilter, KeyOwnerProofSystem, LinearStoragePrice, Nothing, ProcessMessage,
-		ProcessMessageError, VariantCountOf, WithdrawReasons,
+		fungible::{Credit, HoldConsideration},
+		tokens::UnityOrOuterConversion,
+		AsEnsureOriginWithArg, ConstU32, Contains, EitherOf, EitherOfDiverse, EnsureOriginWithArg,
+		FromContains, Imbalance, InstanceFilter, KeyOwnerProofSystem, LinearStoragePrice, Nothing,
+		OnUnbalanced, ProcessMessage, ProcessMessageError, VariantCountOf, WithdrawReasons,
 	},
 	weights::{ConstantMultiplier, WeightMeter},
 	PalletId,
@@ -479,11 +480,43 @@ parameter_types! {
 	/// This value increases the priority of `Operational` transactions by adding
 	/// a "virtual tip" that's equal to the `OperationalFeeMultiplier * final_fee`.
 	pub const OperationalFeeMultiplier: u8 = 5;
+	/// Percentage of fees that go to DAP satellite (0-100).
+	/// The remainder goes to block author. Tips always go 100% to author.
+	/// Westend: 0% to DAP (preserving original behavior of 100% to author)
+	/// Polkadot/Kusama: configurable (e.g., 80% to DAP, 20% to author)
+	pub const DapSatelliteFeePercent: u32 = 0;
+}
+
+/// Fee handler that splits fees between DAP satellite and block author.
+/// - `DapSatelliteFeePercent`% of fees go to DAP satellite
+/// - (100 - `DapSatelliteFeePercent`)% of fees go to block author
+/// - 100% of tips go to block author
+pub struct DealWithFeesSatellite;
+impl OnUnbalanced<Credit<AccountId, Balances>> for DealWithFeesSatellite {
+	fn on_unbalanceds(mut fees_then_tips: impl Iterator<Item = Credit<AccountId, Balances>>) {
+		if let Some(fees) = fees_then_tips.next() {
+			let dap_percent = DapSatelliteFeePercent::get();
+			let author_percent = 100u32.saturating_sub(dap_percent);
+			let mut split = fees.ration(dap_percent, author_percent);
+			if let Some(tips) = fees_then_tips.next() {
+				// For tips: 100% to author
+				tips.merge_into(&mut split.1);
+			}
+			// Send configured % to DAP satellite (if any)
+			if dap_percent > 0 {
+				<pallet_dap_satellite::SlashToSatellite<Runtime> as OnUnbalanced<_>>::on_unbalanced(
+					split.0,
+				);
+			}
+			// Send remainder + tips to author
+			<ToAuthor<Runtime> as OnUnbalanced<_>>::on_unbalanced(split.1);
+		}
+	}
 }
 
 impl pallet_transaction_payment::Config for Runtime {
 	type RuntimeEvent = RuntimeEvent;
-	type OnChargeTransaction = FungibleAdapter<Balances, ToAuthor<Runtime>>;
+	type OnChargeTransaction = FungibleAdapter<Balances, DealWithFeesSatellite>;
 	type OperationalFeeMultiplier = OperationalFeeMultiplier;
 	type WeightToFee = WeightToFee;
 	type LengthToFee = ConstantMultiplier<Balance, TransactionByteFee>;
@@ -1747,6 +1780,10 @@ impl pallet_root_offences::Config for Runtime {
 	type ReportOffence = Offences;
 }
 
+impl pallet_dap_satellite::Config for Runtime {
+	type Currency = Balances;
+}
+
 parameter_types! {
 	pub MbmServiceWeight: Weight = Perbill::from_percent(80) * BlockWeights::get().max_block;
 }
@@ -2027,6 +2064,10 @@ mod runtime {
 	#[runtime::pallet_index(105)]
 	pub type RootOffences = pallet_root_offences;
 
+	// DAP Satellite - collects funds for transfer to DAP on AssetHub
+	#[runtime::pallet_index(106)]
+	pub type DapSatellite = pallet_dap_satellite;
+
 	// BEEFY Bridges support.
 	#[runtime::pallet_index(200)]
 	pub type Beefy = pallet_beefy;

polkadot/runtime/westend/src/lib.rs

@@ -16,8 +16,10 @@ doc:
       on system chains like Coretime, People and BridheHub and on the RelayChain. It should not be deployed
       on AssetHub, which hosts the central DAP pallet.
 
-    asset-hub-westend-runtime and staking-async test runtime have been modified to include pallet-dap and to send part of slashing and treasury's unspent funds to pallet-dap.
-    coretime-westend-runtime has been updated to include pallet-dap-satellite. Coretime revenues are now accumulated in the pallet-dap-satellite account instead of being burned.
+    Runtime changes:
+      - westend-runtime has been updated to include pallet-dap-satellite. It preserves the original behavior for which 100% of tx fees are redirected to the block author.  
+      - asset-hub-westend-runtime and staking-async test runtime have been modified to include pallet-dap and to send part of slashing and treasury's unspent funds to pallet-dap.
+      - coretime-westend-runtime has been updated to include pallet-dap-satellite. Coretime revenues are now accumulated in the pallet-dap-satellite account instead of being burned.
 crates:
 - name: frame-support
   bump: major