- optimized code, added protection & fixed tests

interactors/nonceHandlerV2/addressNonceHandler.go

@@ -189,12 +189,9 @@ func (anh *addressNonceHandler) getOlderTxWithSameNonce(tx *transaction.Frontend
 	anh.mut.RLock()
 	defer anh.mut.RUnlock()
 
-	for _, oldTx := range anh.transactions {
-		if oldTx.Nonce == tx.Nonce {
-			return oldTx
-		}
-	}
-	return nil
+	olderTx, _ := anh.transactions[tx.Nonce]
+
+	return olderTx
 }
 
 // IsInterfaceNil returns true if there is no value under the interface

interactors/nonceHandlerV2/nonceTransactionsHandler.go

@@ -125,7 +125,11 @@ func (nth *nonceTransactionsHandlerV2) SendTransaction(ctx context.Context, tx *
 		return "", interactors.ErrNilTransaction
 	}
 
-	addrAsBech32 := tx.Sender
+	// Work with a full copy of the provided transaction so the provided one can change without affecting this component.
+	// Abnormal and unpredictable behaviors due to the resending mechanism are prevented this way
+	txCopy := *tx
+
+	addrAsBech32 := txCopy.Sender
 	address, err := data.NewAddressFromBech32String(addrAsBech32)
 	if err != nil {
 		return "", fmt.Errorf("%w while creating address handler for string %s", err, addrAsBech32)
@@ -136,7 +140,7 @@ func (nth *nonceTransactionsHandlerV2) SendTransaction(ctx context.Context, tx *
 		return "", err
 	}
 
-	sentHash, err := anh.SendTransaction(ctx, tx)
+	sentHash, err := anh.SendTransaction(ctx, &txCopy)
 	if err != nil {
 		return "", fmt.Errorf("%w while sending transaction for address %s", err, addrAsBech32)
 	}

interactors/nonceHandlerV2/nonceTransactionsHandler_test.go

@@ -365,7 +365,8 @@ func TestNonceTransactionsHandlerV2_SendTransactionsWithGetNonce(t *testing.T) {
 }
 
 func TestNonceTransactionsHandlerV2_SendDuplicateTransactions(t *testing.T) {
-	currentNonce := uint64(664)
+	initialNonce := uint64(664)
+	currentNonce := initialNonce
 
 	numCalls := 0
 
@@ -383,7 +384,7 @@ func TestNonceTransactionsHandlerV2_SendDuplicateTransactions(t *testing.T) {
 		},
 		SendTransactionCalled: func(tx *transaction.FrontendTransaction) (string, error) {
 			require.LessOrEqual(t, numCalls, 1)
-			currentNonce++
+			atomic.AddUint64(&currentNonce, 1)
 			return "", nil
 		},
 	}
@@ -409,15 +410,15 @@ func TestNonceTransactionsHandlerV2_SendDuplicateTransactions(t *testing.T) {
 	require.True(t, ok)
 
 	// after sending first tx, nonce shall increase
-	require.Equal(t, accWithPrivateAccess.computedNonce+1, currentNonce)
+	require.Equal(t, atomic.LoadUint64(&currentNonce), accWithPrivateAccess.computedNonce+1)
 
 	// trying to apply nonce for the same tx, NonceTransactionHandler shall return ErrTxAlreadySent
 	// and computedNonce shall not increase
-	tx.Nonce = 0
+	tx.Nonce = initialNonce
 	err = nth.ApplyNonceAndGasPrice(context.Background(), testAddress, tx)
-	require.Equal(t, err, interactors.ErrTxWithSameNonceAndGasPriceAlreadySent)
-	require.Equal(t, tx.Nonce, uint64(0))
-	require.Equal(t, accWithPrivateAccess.computedNonce+1, currentNonce)
+	require.Equal(t, interactors.ErrTxWithSameNonceAndGasPriceAlreadySent, err)
+	require.Equal(t, initialNonce, tx.Nonce)
+	require.Equal(t, currentNonce, accWithPrivateAccess.computedNonce+1)
 }
 
 func createMockTransactionsWithGetNonce(