Merge pull request #300 from input-output-hk/fix/chained-tx-doublespend

fix(wallet): consume chained tx outputs
input-output-hk · Jun 24, 2022 · db38b1c · db38b1c
2 parents 882edbf + f051351
commit db38b1c
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Showing 2 changed files with 55 additions and 28 deletions.
diff --git a/packages/wallet/src/services/UtxoTracker.ts b/packages/wallet/src/services/UtxoTracker.ts
@@ -57,9 +57,17 @@ export const createUtxoTracker = (
             inputs.some((input) => input.txId === utxoTxIn.txId && input.index === utxoTxIn.index)
           )
       ),
-      ...transactionsInFlight.flatMap((tx) =>
+      ...transactionsInFlight.flatMap((tx, txInFlightIndex) =>
         tx.body.outputs
-          .filter(({ address }) => ownAddresses.includes(address))
+          .filter(
+            ({ address }, outputIndex) =>
+              ownAddresses.includes(address) &&
+              // not already consumed by another tx in flight
+              !transactionsInFlight.some(
+                ({ body: { inputs } }, i) =>
+                  txInFlightIndex !== i && inputs.some((txIn) => txIn.txId === tx.id && txIn.index === outputIndex)
+              )
+          )
           .map(
             (txOut): Cardano.Utxo => [
               {

diff --git a/packages/wallet/test/services/UtxoTracker.test.ts b/packages/wallet/test/services/UtxoTracker.test.ts
@@ -12,39 +12,62 @@ describe('createUtxoTracker', () => {
   let tipBlockHeight$: Observable<number>;
   let utxoProvider: UtxoProvider;
 
-  it('fetches utxo from WalletProvider and includes change from a transaction in flight', () => {
+  it(`fetches utxo from UtxoProvider;
+      includes change from a transaction in flight;
+      deeply chained transactions consumes chainable utxo`, () => {
     const store = new InMemoryUtxoStore();
     const ownAddress = utxo[0][1].address;
     const spendAddress = utxo[1][0].address;
     const spendUtxo = utxo[0];
     const spendTotalCoins = spendUtxo[1].value.coins;
     const spendCoins = spendTotalCoins / 2n;
-    const spendOutput: Cardano.TxOut = {
+    const tx1SpendOutput: Cardano.TxOut = {
       address: spendAddress,
       value: {
         coins: spendCoins
       }
     };
-    const changeOutput: Cardano.TxOut = {
+    const tx1ChangeOutput: Cardano.TxOut = {
       address: ownAddress,
       value: {
         coins: spendTotalCoins - spendCoins
       }
     };
-    const transactionId = Cardano.TransactionId('4123d70f66414cc921f6ffc29a899aafc7137a99a0fd453d6b200863ef5702d6');
-    const outputs = [spendOutput, changeOutput];
+    const transactionId1 = Cardano.TransactionId('4123d70f66414cc921f6ffc29a899aafc7137a99a0fd453d6b200863ef5702d6');
+    const transactionId2 = Cardano.TransactionId('4123d70f66414cc921f6ffc29a899aafc7137a99a0fd453d6b200863ef5702d7');
+    const tx1Outputs = [tx1SpendOutput, tx1ChangeOutput];
+    const tx2Output = {
+      address: ownAddress,
+      value: tx1ChangeOutput.value
+    };
+    const tx2Outputs = [tx2Output];
     createTestScheduler().run(({ cold, expectObservable }) => {
-      const transactionsInFlight$ = cold('-a-b|', {
+      const inFlightTx1 = {
+        body: {
+          inputs: [spendUtxo[0]],
+          outputs: tx1Outputs
+        },
+        id: transactionId1
+      } as unknown as Cardano.NewTxAlonzo;
+      const chainableUtxoFromTx1 = [
+        { address: ownAddress, index: tx1Outputs.indexOf(tx1ChangeOutput), txId: transactionId1 },
+        tx1ChangeOutput
+      ] as Cardano.Utxo;
+      const chainableUtxoFromTx2 = [
+        { address: ownAddress, index: tx2Outputs.indexOf(tx2Output), txId: transactionId2 },
+        tx2Output
+      ] as Cardano.Utxo;
+      const inFlightTx2 = {
+        body: {
+          inputs: [chainableUtxoFromTx1[0]],
+          outputs: tx2Outputs
+        },
+        id: transactionId2
+      } as unknown as Cardano.NewTxAlonzo;
+      const transactionsInFlight$ = cold('-a-b-c|', {
         a: [],
-        b: [
-          {
-            body: {
-              inputs: [spendUtxo[0]],
-              outputs
-            },
-            id: transactionId
-          } as unknown as Cardano.NewTxAlonzo
-        ]
+        b: [inFlightTx1],
+        c: [inFlightTx1, inFlightTx2]
       });
       const utxoTracker = createUtxoTracker(
         {
@@ -69,23 +92,19 @@ describe('createUtxoTracker', () => {
           utxoSource$: cold('a---|', { a: utxo }) as unknown as PersistentCollectionTrackerSubject<Cardano.Utxo>
         }
       );
-      const utxoWithTxInFlight = [
-        ...utxo.slice(1),
-        [
-          { address: ownAddress, index: outputs.indexOf(changeOutput), txId: transactionId },
-          changeOutput
-        ] as Cardano.Utxo
-      ];
-      expectObservable(utxoTracker.total$).toBe('-a-b|', { a: utxo, b: utxoWithTxInFlight });
+      const utxoWithTx1InFlight = [...utxo.slice(1), chainableUtxoFromTx1];
+      const utxoWithTx2InFlight = [...utxo.slice(1), chainableUtxoFromTx2];
+      expectObservable(utxoTracker.total$).toBe('-a-b-c|', { a: utxo, b: utxoWithTx1InFlight, c: utxoWithTx2InFlight });
       expectObservable(utxoTracker.unspendable$).toBe('a---|', { a: [] });
-      expectObservable(utxoTracker.available$).toBe('-a-b|', {
+      expectObservable(utxoTracker.available$).toBe('-a-b-c|', {
         a: utxo,
-        b: utxoWithTxInFlight
+        b: utxoWithTx1InFlight,
+        c: utxoWithTx2InFlight
       });
     });
   });
 
-  it('fetches utxo from WalletProvider and locks unspendable ones', () => {
+  it('fetches utxo from UtxoProvider and locks unspendable ones', () => {
     const store = new InMemoryUtxoStore();
     const address = utxo[0][0].address;
     createTestScheduler().run(({ cold, expectObservable }) => {