fix(core): withdrawal calculation in computeImplicitCoin

Author: przemyslaw-wlodek

Diff for: packages/core/src/Cardano/util/computeImplicitCoin.ts

@@ -30,6 +30,14 @@ const stakeCredentialInRewardAccounts = (
   return rewardAccounts.includes(Address.RewardAccount.fromCredential(stakeCredential, networkId));
 };
 
+const stakeAddressInRewardAccounts = (
+  stakeAddress: Address.RewardAccount,
+  rewardAccounts: Address.RewardAccount[]
+): boolean => {
+  if (rewardAccounts.length === 0) return true;
+  return rewardAccounts.includes(stakeAddress);
+};
+
 const computeShellyDeposits = (
   depositParams: DepositProtocolParams,
   certificates: Cardano.Certificate[],
@@ -179,7 +187,11 @@ export const computeImplicitCoin = (
     proposalProcedures
   );
 
-  const withdrawalsTotal = (withdrawals && BigIntMath.sum(withdrawals.map(({ quantity }) => quantity))) || 0n;
+  const ownWithdrawals =
+    rewardAccounts && withdrawals
+      ? withdrawals.filter((withdrawal) => stakeAddressInRewardAccounts(withdrawal.stakeAddress, rewardAccounts))
+      : [];
+  const withdrawalsTotal = BigIntMath.sum(ownWithdrawals.map(({ quantity }) => quantity)) || 0n;
 
   return {
     deposit,

Diff for: packages/core/test/Cardano/util/computeImplicitCoin.test.ts

@@ -203,6 +203,20 @@ describe('Cardano.util.computeImplicitCoin', () => {
     expect(coin.withdrawals).toBe(withdrawals[0].quantity);
   });
 
+  it('sums withdrawals for input for own reward accounts', () => {
+    const protocolParameters = { dRepDeposit: 5, poolDeposit: 3, stakeKeyDeposit: 2 } as Cardano.ProtocolParameters;
+    const certificates: Cardano.Certificate[] = [];
+    const foreignRewardAccount = Cardano.RewardAccount(
+      'stake_test17rphkx6acpnf78fuvxn0mkew3l0fd058hzquvz7w36x4gtcljw6kf'
+    );
+    const withdrawals: Cardano.Withdrawal[] = [
+      { quantity: 15n, stakeAddress: foreignRewardAccount },
+      { quantity: 5n, stakeAddress: rewardAccount }
+    ];
+    const coin = Cardano.util.computeImplicitCoin(protocolParameters, { certificates, withdrawals }, [rewardAccount]);
+    expect(coin.withdrawals).toBe(5n);
+  });
+
   it('sums certificates and proposal procedures for deposit', () => {
     const protocolParameters = { governanceActionDeposit: 4, stakeKeyDeposit: 2 } as Cardano.ProtocolParameters;
     const governanceActionDeposit = BigInt(protocolParameters.governanceActionDeposit!);