fix: stableswap asset order

math/Cargo.toml

@@ -6,7 +6,7 @@ license = 'Apache-2.0'
 name = "hydra-dx-math"
 description = "A collection of utilities to make performing liquidity pool calculations more convenient."
 repository = 'https://github.com/galacticcouncil/hydradx-math'
-version = "7.4.1"
+version = "7.4.2"
 
 [dependencies]
 primitive-types = {default-features = false, version = '0.12.0'}

math/src/stableswap/tests/multi_assets.rs

@@ -347,3 +347,111 @@ fn calculate_withdraw_should_return_correct_amount_when_removing_provided_shares
 
 	assert_eq!(result, (4993u128, 0u128));
 }
+
+#[test]
+fn calculate_out_given_in_with_fee_should_work_when_reserves_have_different_precision() {
+	let amp = 1000_u128;
+
+	let balances: [Balance; 3] = [1_000_000_000, 3_000_000_000, 5_000_000_000_000_000_000_000];
+
+	let result = calculate_out_given_in_with_fee::<D_ITERATIONS, Y_ITERATIONS>(
+		&balances,
+		1,
+		2,
+		1_000_000,
+		amp,
+		Permill::from_percent(1),
+	);
+	assert_eq!(result.unwrap(), (824_786_715_118_092_963, 8_331_178_940_586_797));
+
+	let result = calculate_out_given_in_with_fee::<D_ITERATIONS, Y_ITERATIONS>(
+		&balances,
+		2,
+		1,
+		1_000_000_000_000_000_000,
+		amp,
+		Permill::from_percent(1),
+	);
+	assert_eq!(result.unwrap(), (1_187_653, 11996));
+}
+
+#[test]
+fn calculate_out_given_in_with_zero_fee_should_work_when_reserves_have_different_precision() {
+	let amp = 1000_u128;
+
+	let balances: [Balance; 3] = [1_000_000_000, 3_000_000_000, 5_000_000_000_000_000_000_000];
+
+	let result = calculate_out_given_in_with_fee::<D_ITERATIONS, Y_ITERATIONS>(
+		&balances,
+		1,
+		2,
+		1_000_000,
+		amp,
+		Permill::from_percent(0),
+	);
+	assert_eq!(result.unwrap(), (824_786_715_118_092_963 + 8_331_178_940_586_797, 0));
+
+	let result = calculate_out_given_in_with_fee::<D_ITERATIONS, Y_ITERATIONS>(
+		&balances,
+		2,
+		1,
+		1_000_000_000_000_000_000,
+		amp,
+		Permill::from_percent(0),
+	);
+	assert_eq!(result.unwrap(), (1_187_653 + 11996, 0));
+}
+
+#[test]
+fn calculate_in_given_out_with_fee_should_work_when_reserves_have_different_precision() {
+	let amp = 1000_u128;
+
+	let balances: [Balance; 3] = [1_000_000_000, 3_000_000_000, 5_000_000_000_000_000_000_000];
+
+	let result = calculate_in_given_out_with_fee::<D_ITERATIONS, Y_ITERATIONS>(
+		&balances,
+		1,
+		2,
+		1_000_000_000_000_000_000,
+		amp,
+		Permill::from_percent(1),
+	);
+	assert_eq!(result.unwrap(), (1212376, 12004));
+
+	let result = calculate_in_given_out_with_fee::<D_ITERATIONS, Y_ITERATIONS>(
+		&balances,
+		2,
+		1,
+		1_000_000,
+		amp,
+		Permill::from_percent(1),
+	);
+	assert_eq!(result.unwrap(), (841869902748480839, 8335345571767138));
+}
+
+#[test]
+fn calculate_in_given_out_with_zero_fee_should_work_when_reserves_have_different_precision() {
+	let amp = 1000_u128;
+
+	let balances: [Balance; 3] = [1_000_000_000, 3_000_000_000, 5_000_000_000_000_000_000_000];
+
+	let result = calculate_in_given_out_with_fee::<D_ITERATIONS, Y_ITERATIONS>(
+		&balances,
+		1,
+		2,
+		1_000_000_000_000_000_000,
+		amp,
+		Permill::from_percent(0),
+	);
+	assert_eq!(result.unwrap(), (1212376 - 12004, 0));
+
+	let result = calculate_in_given_out_with_fee::<D_ITERATIONS, Y_ITERATIONS>(
+		&balances,
+		2,
+		1,
+		1_000_000,
+		amp,
+		Permill::from_percent(0),
+	);
+	assert_eq!(result.unwrap(), (841869902748480839 - 8335345571767138, 0));
+}

pallets/stableswap/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = 'pallet-stableswap'
-version = '2.1.0'
+version = '2.1.1'
 description = 'AMM for correlated assets'
 authors = ['GalacticCouncil']
 edition = '2021'

pallets/stableswap/src/lib.rs

@@ -631,7 +631,6 @@ pub mod pallet {
 			ensure!(amount_out >= min_buy_amount, Error::<T>::BuyLimitNotReached);
 
 			let pool_account = Self::pool_account(pool_id);
-
 			T::Currency::transfer(asset_in, &who, &pool_account, amount_in)?;
 			T::Currency::transfer(asset_out, &pool_account, &who, amount_out)?;
 
@@ -746,8 +745,8 @@ pub mod pallet {
 impl<T: Config> Pallet<T> {
 	fn calculate_out_amount(
 		pool_id: T::AssetId,
-		asset_out: T::AssetId,
 		asset_in: T::AssetId,
+		asset_out: T::AssetId,
 		amount_in: Balance,
 	) -> Result<(Balance, Balance), DispatchError> {
 		let pool = Pools::<T>::get(pool_id).ok_or(Error::<T>::PoolNotFound)?;

pallets/stableswap/src/tests/trades.rs

@@ -502,3 +502,141 @@ fn buy_should_fail_when_insufficient_amount_is_provided() {
 			);
 		});
 }
+
+#[test]
+fn sell_should_work_when_pool_have_asset_with_various_decimals() {
+	let asset_a: AssetId = 1;
+	let asset_b: AssetId = 2;
+	let asset_c: AssetId = 3;
+	ExtBuilder::default()
+		.with_endowed_accounts(vec![(BOB, 1, 200 * ONE), (ALICE, 1, 200 * ONE), (ALICE, 2, 200 * ONE)])
+		.with_registered_asset("one".as_bytes().to_vec(), 1)
+		.with_registered_asset("two".as_bytes().to_vec(), 2)
+		.with_registered_asset("three".as_bytes().to_vec(), 3)
+		.with_endowed_accounts(vec![
+			(BOB, asset_c, ONE * 1_000_000),
+			(ALICE, asset_a, 2000 * ONE),
+			(ALICE, asset_b, 4000 * ONE),
+			(ALICE, asset_c, 10000 * ONE * 1_000_000),
+		])
+		.with_pool(
+			ALICE,
+			PoolInfo::<AssetId, u64> {
+				assets: vec![asset_a, asset_b, asset_c].try_into().unwrap(),
+				initial_amplification: NonZeroU16::new(1000).unwrap(),
+				final_amplification: NonZeroU16::new(1000).unwrap(),
+				initial_block: 0,
+				trade_fee: Permill::from_percent(0),
+				withdraw_fee: Permill::from_percent(0),
+				final_block: 0,
+			},
+			InitialLiquidity {
+				account: ALICE,
+				assets: vec![
+					AssetBalance {
+						asset_id: asset_a,
+						amount: 1_000_000_000,
+					},
+					AssetBalance {
+						asset_id: asset_b,
+						amount: 3_000_000_000,
+					},
+					AssetBalance {
+						asset_id: asset_c,
+						amount: 5000 * ONE * 1_000_000,
+					},
+				],
+			},
+		)
+		.build()
+		.execute_with(|| {
+			let pool_id = get_pool_id_at(0);
+
+			assert_ok!(Stableswap::sell(
+				RuntimeOrigin::signed(BOB),
+				pool_id,
+				asset_c,
+				asset_b,
+				ONE * 1_000_000,
+				0,
+			));
+
+			let expected = 1_199_649;
+
+			let pool_account = pool_account(pool_id);
+
+			assert_balance!(BOB, asset_c, 0);
+			assert_balance!(BOB, asset_b, expected);
+			assert_balance!(pool_account, asset_c, 5_001_000_000_000_000_000_000);
+			assert_balance!(pool_account, asset_b, 3_000_000_000 - expected);
+		});
+}
+
+#[test]
+fn buy_should_work_when_pool_have_asset_with_various_decimals() {
+	let asset_a: AssetId = 1;
+	let asset_b: AssetId = 2;
+	let asset_c: AssetId = 3;
+	ExtBuilder::default()
+		.with_endowed_accounts(vec![(BOB, 1, 200 * ONE), (ALICE, 1, 200 * ONE), (ALICE, 2, 200 * ONE)])
+		.with_registered_asset("one".as_bytes().to_vec(), 1)
+		.with_registered_asset("two".as_bytes().to_vec(), 2)
+		.with_registered_asset("three".as_bytes().to_vec(), 3)
+		.with_endowed_accounts(vec![
+			(BOB, asset_c, ONE * 1_000_000),
+			(ALICE, asset_a, 2000 * ONE),
+			(ALICE, asset_b, 4000 * ONE),
+			(ALICE, asset_c, 10000 * ONE * 1_000_000),
+		])
+		.with_pool(
+			ALICE,
+			PoolInfo::<AssetId, u64> {
+				assets: vec![asset_a, asset_b, asset_c].try_into().unwrap(),
+				initial_amplification: NonZeroU16::new(1000).unwrap(),
+				final_amplification: NonZeroU16::new(1000).unwrap(),
+				initial_block: 0,
+				trade_fee: Permill::from_percent(0),
+				withdraw_fee: Permill::from_percent(0),
+				final_block: 0,
+			},
+			InitialLiquidity {
+				account: ALICE,
+				assets: vec![
+					AssetBalance {
+						asset_id: asset_a,
+						amount: 1_000_000_000,
+					},
+					AssetBalance {
+						asset_id: asset_b,
+						amount: 3_000_000_000,
+					},
+					AssetBalance {
+						asset_id: asset_c,
+						amount: 5000 * ONE * 1_000_000,
+					},
+				],
+			},
+		)
+		.build()
+		.execute_with(|| {
+			let pool_id = get_pool_id_at(0);
+
+			assert_ok!(Stableswap::buy(
+				RuntimeOrigin::signed(BOB),
+				pool_id,
+				asset_b,
+				asset_c,
+				1_199_649,
+				2 * ONE * 1_000_000,
+			));
+
+			let expected = 1_199_649;
+
+			let pool_account = pool_account(pool_id);
+
+			assert_balance!(BOB, asset_c, 1_174_293_340_450);
+			assert_balance!(BOB, asset_b, expected);
+			assert_balance!(pool_account, asset_c, 5000999998825706659550);
+			assert_balance!(pool_account, asset_b, 3_000_000_000 - expected);
+		});
+}