chore: address review

state-chain/custom-rpc/src/lib.rs

@@ -565,7 +565,7 @@ mod boost_pool_rpc {
 		available_amounts: Vec<AccountAndAmount>,
 		deposits_pending_finalization: Vec<PendingBoost>,
 		pending_withdrawals: Vec<PendingWithdrawal>,
-		network_fee_deduction_percents: Percent,
+		network_fee_deduction_percent: Percent,
 	}
 
 	impl BoostPoolDetailsRpc {
@@ -603,7 +603,7 @@ mod boost_pool_rpc {
 						pending_deposits,
 					})
 					.collect(),
-				network_fee_deduction_percents: details.network_fee_deduction_percents,
+				network_fee_deduction_percent: details.network_fee_deduction_percent,
 			}
 		}
 	}
@@ -2424,7 +2424,7 @@ mod test {
 				(1, BTreeMap::from([(ID_1.clone(), OwedAmount { total: 1_000, fee: 50 })])),
 			]),
 			pending_withdrawals: Default::default(),
-			network_fee_deduction_percents: Percent::from_percent(40),
+			network_fee_deduction_percent: Percent::from_percent(40),
 		}
 	}
 
@@ -2442,7 +2442,7 @@ mod test {
 				(ID_1.clone(), BTreeSet::from([0])),
 				(ID_2.clone(), BTreeSet::from([0])),
 			]),
-			network_fee_deduction_percents: Percent::from_percent(0),
+			network_fee_deduction_percent: Percent::from_percent(0),
 		}
 	}
 

state-chain/custom-rpc/src/snapshots/custom_rpc__test__boost_details_serialization.snap

@@ -38,7 +38,7 @@ expression: val
       }
     ],
     "pending_withdrawals": [],
-    "network_fee_deduction_percents": 40
+    "network_fee_deduction_percent": 40
   },
   {
     "fee_tier": 30,
@@ -74,6 +74,6 @@ expression: val
         ]
       }
     ],
-    "network_fee_deduction_percents": 0
+    "network_fee_deduction_percent": 0
   }
 ]

state-chain/pallets/cf-ingress-egress/src/boost_pool.rs

@@ -152,7 +152,7 @@ where
 	AccountId: PartialEq + core::fmt::Debug,
 {
 	pub unlocked_funds: Vec<(AccountId, C::ChainAmount)>,
-	pub amount_credited: C::ChainAmount,
+	pub amount_credited_to_boosters: C::ChainAmount,
 }
 
 impl<AccountId, C: Chain> BoostPool<AccountId, C>
@@ -250,8 +250,8 @@ where
 			(provided_amount, fee)
 		};
 
-		// NOTE: only a portion of the boost fee goes to the boost pool,
-		// the rest is charged as network fee:
+		// NOTE: before the boost fee is credited to the boost pool, a portion
+		// of it is deducted as network fee:
 		let network_fee = network_fee_deduction * u128::from(fee_amount);
 		let boost_pool_fee = fee_amount.saturating_sub(ScaledAmount::from(network_fee));
 
@@ -393,7 +393,7 @@ where
 
 		DepositFinalisationOutcomeForPool {
 			unlocked_funds,
-			amount_credited: amount_credited.into_chain_amount(),
+			amount_credited_to_boosters: amount_credited.into_chain_amount(),
 		}
 	}
 

state-chain/pallets/cf-ingress-egress/src/boost_pool/tests.rs

@@ -1,6 +1,6 @@
 use super::*;
 use cf_chains::Ethereum;
-use cf_primitives::{AssetAmount, EthAmount, FLIPPERINOS_PER_FLIP};
+use cf_primitives::{AssetAmount, EthAmount, FLIPPERINOS_PER_FLIP, MAX_BASIS_POINTS};
 
 use sp_std::collections::btree_set::BTreeSet;
 
@@ -172,25 +172,73 @@ fn boosting_with_fees() {
 
 	assert_eq!(
 		pool.process_deposit_as_finalised(BOOST_1),
-		DepositFinalisationOutcomeForPool { amount_credited: 1010, unlocked_funds: vec![] }
+		DepositFinalisationOutcomeForPool {
+			amount_credited_to_boosters: 1010,
+			unlocked_funds: vec![]
+		}
 	);
 
 	check_pool(&pool, [(BOOSTER_1, 1003), (BOOSTER_2, 2006)]);
 }
 
+#[test]
+fn boosting_with_max_network_fee_deduction() {
+	const BOOST_FEE_BPS: u16 = 100;
+	const INIT_BOOSTER_AMOUNT: u128 = 2000;
+	const NETWORK_FEE_PORTION_PERCENT: u8 = 100;
+
+	let mut pool = TestPool::new(BOOST_FEE_BPS);
+
+	pool.add_funds(BOOSTER_1, INIT_BOOSTER_AMOUNT);
+
+	check_pool(&pool, [(BOOSTER_1, INIT_BOOSTER_AMOUNT)]);
+
+	const PROVIDED_AMOUNT: u128 = 1000;
+	const FULL_BOOST_FEE: u128 =
+		(PROVIDED_AMOUNT * BOOST_FEE_BPS as u128) / MAX_BASIS_POINTS as u128;
+
+	const DEPOSIT_AMOUNT: u128 = PROVIDED_AMOUNT + FULL_BOOST_FEE;
+
+	// NOTE: Full 1% boost fee is charged from the deposit
+	assert_eq!(
+		pool.provide_funds_for_boosting(
+			BOOST_1,
+			DEPOSIT_AMOUNT,
+			Percent::from_percent(NETWORK_FEE_PORTION_PERCENT)
+		),
+		Ok((DEPOSIT_AMOUNT, FULL_BOOST_FEE))
+	);
+
+	// Booster's contribution is recorded, but they earn 0 fees:
+	check_pending_boosts(&pool, [(BOOST_1, vec![(BOOSTER_1, 1000, 0)])]);
+
+	assert_eq!(
+		pool.process_deposit_as_finalised(BOOST_1),
+		DepositFinalisationOutcomeForPool {
+			amount_credited_to_boosters: 0,
+			unlocked_funds: vec![]
+		}
+	);
+
+	// No change in the boost pool after deposit is finalised:
+	check_pool(&pool, [(BOOSTER_1, INIT_BOOSTER_AMOUNT)]);
+}
+
 #[test]
 fn boosting_with_fees_including_network_fee_portion() {
 	const NETWORK_FEE_PORTION_PERCENT: u8 = 30;
+	const BOOST_FEE_BPS: u16 = 100;
 
-	let mut pool = TestPool::new(100); // 1%
+	let mut pool = TestPool::new(BOOST_FEE_BPS);
 
 	pool.add_funds(BOOSTER_1, 1000);
 	pool.add_funds(BOOSTER_2, 2000);
 
 	check_pool(&pool, [(BOOSTER_1, 1000), (BOOSTER_2, 2000)]);
 
 	const PROVIDED_AMOUNT: u128 = 1000;
-	const FULL_BOOST_FEE: u128 = 10;
+	const FULL_BOOST_FEE: u128 =
+		(PROVIDED_AMOUNT * BOOST_FEE_BPS as u128) / MAX_BASIS_POINTS as u128;
 
 	const DEPOSIT_AMOUNT: u128 = PROVIDED_AMOUNT + FULL_BOOST_FEE;
 
@@ -211,8 +259,9 @@ fn boosting_with_fees_including_network_fee_portion() {
 
 	const NETWORK_FEE_FROM_BOOST: u128 = FULL_BOOST_FEE * NETWORK_FEE_PORTION_PERCENT as u128 / 100;
 
-	// NOTE: we subtract 1 to account for a rounding "error" (in real code any remaining fee will be
-	// used as network fee, so all atomic units will be accounted for)
+	// Sanity check: network fee and boosters fee should make up the full boost fee.
+	// Note that we subtract 1 to account for a rounding "error" (in real code any
+	// remaining fee will be used as network fee, so all atomic units will be accounted for).
 	assert_eq!(TOTAL_BOOSTERS_FEE, FULL_BOOST_FEE - NETWORK_FEE_FROM_BOOST - 1);
 
 	// The recorded amounts include fees
@@ -230,7 +279,7 @@ fn boosting_with_fees_including_network_fee_portion() {
 	assert_eq!(
 		pool.process_deposit_as_finalised(BOOST_1),
 		DepositFinalisationOutcomeForPool {
-			amount_credited: PROVIDED_AMOUNT + TOTAL_BOOSTERS_FEE,
+			amount_credited_to_boosters: PROVIDED_AMOUNT + TOTAL_BOOSTERS_FEE,
 			unlocked_funds: vec![]
 		}
 	);
@@ -273,7 +322,7 @@ fn adding_funds_during_pending_withdrawal_from_same_booster() {
 	assert_eq!(
 		pool.process_deposit_as_finalised(BOOST_1),
 		DepositFinalisationOutcomeForPool {
-			amount_credited: DEPOSIT_AMOUNT,
+			amount_credited_to_boosters: DEPOSIT_AMOUNT,
 			unlocked_funds: vec![]
 		}
 	);
@@ -296,7 +345,7 @@ fn withdrawing_funds_before_finalisation() {
 	assert_eq!(
 		pool.process_deposit_as_finalised(BOOST_1),
 		DepositFinalisationOutcomeForPool {
-			amount_credited: 1000,
+			amount_credited_to_boosters: 1000,
 			unlocked_funds: vec![(BOOSTER_1, 500)]
 		}
 	);
@@ -323,7 +372,7 @@ fn adding_funds_with_pending_withdrawals() {
 	assert_eq!(
 		pool.process_deposit_as_finalised(BOOST_1),
 		DepositFinalisationOutcomeForPool {
-			amount_credited: 1000,
+			amount_credited_to_boosters: 1000,
 			unlocked_funds: vec![(BOOSTER_1, 500)]
 		}
 	);
@@ -393,7 +442,7 @@ fn partially_losing_pending_withdrawals() {
 		assert_eq!(
 			pool.process_deposit_as_finalised(BOOST_1),
 			DepositFinalisationOutcomeForPool {
-				amount_credited: 500,
+				amount_credited_to_boosters: 500,
 				unlocked_funds: vec![(BOOSTER_1, 250)]
 			}
 		);
@@ -436,7 +485,7 @@ fn booster_joins_then_funds_lost() {
 	assert_eq!(
 		pool.process_deposit_as_finalised(BOOST_1),
 		DepositFinalisationOutcomeForPool {
-			amount_credited: 500,
+			amount_credited_to_boosters: 500,
 			unlocked_funds: vec![(BOOSTER_1, 250)]
 		}
 	);
@@ -484,7 +533,7 @@ fn booster_joins_between_boosts() {
 	assert_eq!(
 		pool.process_deposit_as_finalised(BOOST_1),
 		DepositFinalisationOutcomeForPool {
-			amount_credited: 500,
+			amount_credited_to_boosters: 500,
 			unlocked_funds: vec![(BOOSTER_1, 250)]
 		},
 	);
@@ -506,7 +555,10 @@ fn booster_joins_between_boosts() {
 		let mut pool = pool.clone();
 		assert_eq!(
 			pool.process_deposit_as_finalised(BOOST_2),
-			DepositFinalisationOutcomeForPool { amount_credited: 1000, unlocked_funds: vec![] }
+			DepositFinalisationOutcomeForPool {
+				amount_credited_to_boosters: 1000,
+				unlocked_funds: vec![]
+			}
 		);
 		check_pool(&pool, [(BOOSTER_2, 1010), (BOOSTER_3, 2014)]);
 		check_pending_boosts(&pool, []);
@@ -531,7 +583,7 @@ fn small_rewards_accumulate() {
 	assert_eq!(
 		pool.process_deposit_as_finalised(BOOST_1),
 		DepositFinalisationOutcomeForPool {
-			amount_credited: SMALL_DEPOSIT,
+			amount_credited_to_boosters: SMALL_DEPOSIT,
 			unlocked_funds: vec![]
 		}
 	);
@@ -549,7 +601,7 @@ fn small_rewards_accumulate() {
 		assert_eq!(
 			pool.process_deposit_as_finalised(prewitnessed_deposit_id),
 			DepositFinalisationOutcomeForPool {
-				amount_credited: SMALL_DEPOSIT,
+				amount_credited_to_boosters: SMALL_DEPOSIT,
 				unlocked_funds: vec![]
 			}
 		);
@@ -580,7 +632,10 @@ fn use_max_available_amount() {
 
 	assert_eq!(
 		pool.process_deposit_as_finalised(BOOST_1),
-		DepositFinalisationOutcomeForPool { amount_credited: 1_010_101, unlocked_funds: vec![] }
+		DepositFinalisationOutcomeForPool {
+			amount_credited_to_boosters: 1_010_101,
+			unlocked_funds: vec![]
+		}
 	);
 
 	check_pool(&pool, [(BOOSTER_1, 1_010_301)]);

state-chain/pallets/cf-ingress-egress/src/lib.rs

@@ -285,7 +285,7 @@ pub enum PalletConfigUpdate<T: Config<I>, I: 'static> {
 		lifetime: TargetChainBlockNumber<T, I>,
 	},
 	SetNetworkFeeDeductionFromBoost {
-		deduction_percents: Percent,
+		deduction_percent: Percent,
 	},
 }
 
@@ -726,7 +726,7 @@ pub mod pallet {
 
 	/// The fraction of the network fee that is deducted from the boost fee.
 	#[pallet::storage]
-	pub type NetworkFeeDeductionFromBoostPercents<T: Config<I>, I: 'static = ()> =
+	pub type NetworkFeeDeductionFromBoostPercent<T: Config<I>, I: 'static = ()> =
 		StorageValue<_, Percent, ValueQuery>;
 
 	#[pallet::event]
@@ -898,7 +898,7 @@ pub mod pallet {
 			short_affiliate_id: AffiliateShortId,
 		},
 		NetworkFeeDeductionFromBoostSet {
-			deduction_percents: Percent,
+			deduction_percent: Percent,
 		},
 	}
 
@@ -1309,11 +1309,11 @@ pub mod pallet {
 						DepositChannelLifetime::<T, I>::set(lifetime);
 						Self::deposit_event(Event::<T, I>::DepositChannelLifetimeSet { lifetime });
 					},
-					PalletConfigUpdate::SetNetworkFeeDeductionFromBoost { deduction_percents } => {
-						NetworkFeeDeductionFromBoostPercents::<T, I>::set(deduction_percents);
+					PalletConfigUpdate::SetNetworkFeeDeductionFromBoost { deduction_percent } => {
+						NetworkFeeDeductionFromBoostPercent::<T, I>::set(deduction_percent);
 
 						Self::deposit_event(Event::<T, I>::NetworkFeeDeductionFromBoostSet {
-							deduction_percents,
+							deduction_percent,
 						});
 					},
 				}
@@ -1781,7 +1781,7 @@ impl<T: Config<I>, I: 'static> Pallet<T, I> {
 			"Boost tiers should be in ascending order"
 		);
 
-		let network_fee_portion = NetworkFeeDeductionFromBoostPercents::<T, I>::get();
+		let network_fee_portion = NetworkFeeDeductionFromBoostPercent::<T, I>::get();
 
 		for boost_tier in sorted_boost_tiers {
 			if boost_tier > max_boost_fee_bps {
@@ -2345,16 +2345,19 @@ impl<T: Config<I>, I: 'static> Pallet<T, I> {
 		};
 
 		if let Some((prewitnessed_deposit_id, used_pools)) = maybe_boost_to_process {
-			let mut total_amount_credited: TargetChainAmount<T, I> = 0u32.into();
+			let mut total_amount_credited_to_boosters: TargetChainAmount<T, I> = 0u32.into();
 			// Note that ingress fee is not payed here, as it has already been payed at the time
 			// of boosting
 			for boost_tier in used_pools {
 				BoostPools::<T, I>::mutate(asset, boost_tier, |maybe_pool| {
 					if let Some(pool) = maybe_pool {
-						let DepositFinalisationOutcomeForPool { unlocked_funds, amount_credited } =
-							pool.process_deposit_as_finalised(prewitnessed_deposit_id);
+						let DepositFinalisationOutcomeForPool {
+							unlocked_funds,
+							amount_credited_to_boosters,
+						} = pool.process_deposit_as_finalised(prewitnessed_deposit_id);
 
-						total_amount_credited += amount_credited;
+						total_amount_credited_to_boosters
+							.saturating_accrue(amount_credited_to_boosters);
 
 						for (booster_id, finalised_withdrawn_amount) in unlocked_funds {
 							T::Balance::credit_account(
@@ -2368,7 +2371,8 @@ impl<T: Config<I>, I: 'static> Pallet<T, I> {
 			}
 
 			// Any excess amount is charged as network fee:
-			let network_fee_from_boost = deposit_amount.saturating_sub(total_amount_credited);
+			let network_fee_from_boost =
+				deposit_amount.saturating_sub(total_amount_credited_to_boosters);
 
 			let network_fee_swap_request_id = if network_fee_from_boost > 0u32.into() {
 				// NOTE: if asset is FLIP, we shouldn't need to swap, but it should still work, and