Added Minor Deviation allowance for withdrawal

pallets/ocex/src/settlement.rs

@@ -19,14 +19,17 @@
 //! Helper functions for updating the balance
 
 use crate::{storage::OffchainState, Config, Pallet};
+use core::ops::Sub;
 use log::{error, info};
+use orderbook_primitives::constants::POLKADEX_MAINNET_SS58;
 use orderbook_primitives::ocex::TradingPairConfig;
 use orderbook_primitives::types::Order;
 use orderbook_primitives::{constants::FEE_POT_PALLET_ID, types::Trade};
 use parity_scale_codec::{alloc::string::ToString, Decode, Encode};
 use polkadex_primitives::{fees::FeeConfig, AccountId, AssetId};
+use rust_decimal::RoundingStrategy::ToZero;
 use rust_decimal::{prelude::ToPrimitive, Decimal};
-use sp_core::crypto::ByteArray;
+use sp_core::crypto::{ByteArray, Ss58AddressFormat, Ss58Codec};
 use sp_runtime::traits::AccountIdConversion;
 use sp_std::collections::btree_map::BTreeMap;
 
@@ -88,7 +91,7 @@ pub fn add_balance(
 /// Updates provided trie db with reducing balance of account asset if it exists in the db.
 ///
 /// If account asset balance does not exists in the db `AccountBalanceNotFound` error will be
-/// returned.
+/// returned. Balance returned is the acutal balance that was deduced accounting for rounding errors/deviation.
 ///
 /// # Parameters
 ///
@@ -100,26 +103,33 @@ pub fn sub_balance(
 	state: &mut OffchainState,
 	account: &AccountId,
 	asset: AssetId,
-	balance: Decimal,
-) -> Result<(), &'static str> {
+	mut balance: Decimal,
+) -> Result<Decimal, &'static str> {
 	log::info!(target:"ocex", "subtracting {:?} asset {:?} from account {:?}", balance.to_f64().unwrap(), asset.to_string(), account);
 	let mut balances: BTreeMap<AssetId, Decimal> = match state.get(&account.to_raw_vec())? {
 		None => return Err("Account not found in trie"),
 		Some(encoded) => BTreeMap::decode(&mut &encoded[..])
 			.map_err(|_| "Unable to decode balances for account")?,
 	};
 
-	let account_balance = balances.get_mut(&asset).ok_or("NotEnoughBalance")?;
+	let account_balance = balances.get_mut(&asset).ok_or("NotEnoughBalance: zero balance")?;
 
 	if *account_balance < balance {
-		log::error!(target:"ocex","Asset found but balance low for asset: {:?}, of account: {:?}",asset, account);
-		return Err("NotEnoughBalance");
+		// If the deviation is smaller that system limit, then we can allow what's stored in the offchain balance
+		let deviation = balance.sub(&*account_balance);
+		if !deviation.round_dp_with_strategy(8, ToZero).is_zero() {
+			log::error!(target:"ocex","Asset found but balance low for asset: {:?}, of account: {:?}",asset, account);
+			return Err("NotEnoughBalance");
+		} else {
+			log::warn!(target:"ocex","Asset found but minor balance deviation of {:?} for asset: {:?}, of account: {:?}",deviation,asset.to_string(), account.to_ss58check_with_version(Ss58AddressFormat::from(POLKADEX_MAINNET_SS58)));
+			balance = *account_balance;
+		}
 	}
 	*account_balance = Order::rounding_off(account_balance.saturating_sub(balance));
 
 	state.insert(account.to_raw_vec(), balances.encode());
 
-	Ok(())
+	Ok(balance)
 }
 
 impl<T: Config> Pallet<T> {

pallets/ocex/src/tests.rs

@@ -316,16 +316,16 @@ fn test_sub_balance_existing_account_with_balance() {
 
 		//sub balance
 		let amount2 = 2000000;
-		let result = sub_balance(&mut state, &account_id, asset_id, amount2.into());
-		assert_eq!(result, Ok(()));
+		let result = sub_balance(&mut state, &account_id, asset_id, amount2.into()).unwrap();
+		assert_eq!(result, amount2.into());
 		let encoded = state.get(&account_id.to_raw_vec()).unwrap().unwrap();
 		let account_info: BTreeMap<AssetId, Decimal> = BTreeMap::decode(&mut &encoded[..]).unwrap();
 		assert_eq!(account_info.get(&asset_id).unwrap(), &(amount - amount2).into());
 
 		//sub balance till 0
 		let amount3 = amount - amount2;
-		let result = sub_balance(&mut state, &account_id, asset_id, amount3.into());
-		assert_eq!(result, Ok(()));
+		let result = sub_balance(&mut state, &account_id, asset_id, amount3.into()).unwrap();
+		assert_eq!(result, amount3.into());
 		let encoded = state.get(&account_id.to_raw_vec()).unwrap().unwrap();
 		let account_info: BTreeMap<AssetId, Decimal> = BTreeMap::decode(&mut &encoded[..]).unwrap();
 		assert_eq!(amount - amount2 - amount3, 0);
@@ -416,8 +416,9 @@ fn test_balance_update_depost_first_then_trade() {
 
 		//sub balance till 0
 		let amount3 = Decimal::from_f64_retain(2.0).unwrap();
-		let result = sub_balance(&mut state, &account_id, AssetId::Polkadex, amount3.into());
-		assert_eq!(result, Ok(()));
+		let result =
+			sub_balance(&mut state, &account_id, AssetId::Polkadex, amount3.into()).unwrap();
+		assert_eq!(result, amount3);
 	});
 }
 
@@ -469,7 +470,7 @@ fn test_trade_between_two_accounts_without_balance() {
 		let result = OCEX::process_trade(&mut state, &trade, config, maker_fees, taker_fees);
 		match result {
 			Ok(_) => assert!(false),
-			Err(e) => assert_eq!(e, "NotEnoughBalance"),
+			Err(e) => assert_eq!(e, "NotEnoughBalance: zero balance"),
 		}
 	});
 }

pallets/ocex/src/validator.rs

@@ -681,15 +681,15 @@ impl<T: Config> Pallet<T> {
 		if !request.verify() {
 			return Err("SignatureVerificationFailed");
 		}
-		sub_balance(
+		let actual_deducted = sub_balance(
 			state,
 			&Decode::decode(&mut &request.main.encode()[..])
 				.map_err(|_| "account id decode error")?,
 			request.asset(),
 			amount,
 		)?;
-		let withdrawal = request.convert(stid).map_err(|_| "Withdrawal conversion error")?;
-
+		let mut withdrawal = request.convert(stid).map_err(|_| "Withdrawal conversion error")?;
+		withdrawal.amount = actual_deducted; // The acutal deducted balance
 		Ok(withdrawal)
 	}
 

runtimes/mainnet/src/lib.rs

@@ -122,7 +122,7 @@ pub const VERSION: RuntimeVersion = RuntimeVersion {
 	// and set impl_version to 0. If only runtime
 	// implementation changes and behavior does not, then leave spec_version as
 	// is and increment impl_version.
-	spec_version: 338,
+	spec_version: 341,
 	impl_version: 0,
 	apis: RUNTIME_API_VERSIONS,
 	transaction_version: 2,

runtimes/parachain/src/lib.rs

@@ -837,6 +837,7 @@ impl_runtime_apis! {
 	}
 }
 
+#[allow(dead_code)]
 struct CheckInherents;
 
 impl cumulus_pallet_parachain_system::CheckInherents<Block> for CheckInherents {

scripts/get_balance_rpc.sh

@@ -3,5 +3,5 @@ curl -H "Content-Type: application/json" -d '{
     "jsonrpc":"2.0",
     "id":1,
     "method":"ob_getBalance",
-    "params":["esr4dJBv5123tkiA3beRZ3TrHbppJ6PdPxo2xHN4rmZJGDQJo",{"asset":"3496813586714279103986568049643838918"}]
+    "params":["espg8YLUhUDVXcrfNMyHqzjBBrrq3HBKj3FBQNq6Hte3p28Eh",{"asset":"95930534000017180603917534864279132680"}]
 }' http://localhost:9944