fix: do not allow creating duplicate pending transactions

transactions/payments_test.go

@@ -88,7 +88,7 @@ func TestSendPaymentSync_MetadataTooLarge(t *testing.T) {
 	assert.Nil(t, transaction)
 }
 
-func TestSendPaymentSync_Duplicate(t *testing.T) {
+func TestSendPaymentSync_Duplicate_AlreadyPaid(t *testing.T) {
 	ctx := context.TODO()
 
 	svc, err := tests.CreateTestService(t)
@@ -110,6 +110,48 @@ func TestSendPaymentSync_Duplicate(t *testing.T) {
 	assert.Nil(t, transaction)
 }
 
+func TestSendPaymentSync_Duplicate_Pending(t *testing.T) {
+	ctx := context.TODO()
+
+	svc, err := tests.CreateTestService(t)
+	require.NoError(t, err)
+	defer svc.Remove()
+
+	svc.DB.Create(&db.Transaction{
+		State:       constants.TRANSACTION_STATE_PENDING,
+		Type:        constants.TRANSACTION_TYPE_OUTGOING,
+		PaymentHash: tests.MockLNClientTransaction.PaymentHash,
+		AmountMsat:  123000,
+	})
+
+	transactionsService := NewTransactionsService(svc.DB, svc.EventPublisher)
+	transaction, err := transactionsService.SendPaymentSync(ctx, tests.MockLNClientTransaction.Invoice, nil, nil, svc.LNClient, nil, nil)
+
+	assert.Error(t, err)
+	assert.Equal(t, "there is already a payment pending for this invoice", err.Error())
+	assert.Nil(t, transaction)
+}
+
+func TestSendPaymentSync_Duplicate_Failed(t *testing.T) {
+	ctx := context.TODO()
+
+	svc, err := tests.CreateTestService(t)
+	require.NoError(t, err)
+	defer svc.Remove()
+
+	svc.DB.Create(&db.Transaction{
+		State:       constants.TRANSACTION_STATE_FAILED,
+		Type:        constants.TRANSACTION_TYPE_OUTGOING,
+		PaymentHash: tests.MockLNClientTransaction.PaymentHash,
+		AmountMsat:  123000,
+	})
+
+	transactionsService := NewTransactionsService(svc.DB, svc.EventPublisher)
+	_, err = transactionsService.SendPaymentSync(ctx, tests.MockLNClientTransaction.Invoice, nil, nil, svc.LNClient, nil, nil)
+
+	assert.NoError(t, err)
+}
+
 func TestMarkSettled_Sent(t *testing.T) {
 	svc, err := tests.CreateTestService(t)
 	require.NoError(t, err)

transactions/transactions_service.go

@@ -232,9 +232,17 @@ func (svc *transactionsService) SendPaymentSync(ctx context.Context, payReq stri
 			PaymentHash: paymentRequest.PaymentHash,
 			State:       constants.TRANSACTION_STATE_SETTLED,
 		}).RowsAffected > 0 {
-			logger.Logger.WithField("payment_hash", dbTransaction.PaymentHash).Info("this invoice has already been paid")
+			logger.Logger.WithField("payment_hash", dbTransaction.PaymentHash).Debug("this invoice has already been paid")
 			return errors.New("this invoice has already been paid")
 		}
+		if tx.Limit(1).Find(&existingSettledTransaction, &db.Transaction{
+			Type:        constants.TRANSACTION_TYPE_OUTGOING,
+			PaymentHash: paymentRequest.PaymentHash,
+			State:       constants.TRANSACTION_STATE_PENDING,
+		}).RowsAffected > 0 {
+			logger.Logger.WithField("payment_hash", dbTransaction.PaymentHash).Debug("this invoice is already being paid")
+			return errors.New("there is already a payment pending for this invoice")
+		}
 
 		err := svc.validateCanPay(tx, appId, paymentAmount, paymentRequest.Description)
 		if err != nil {
@@ -953,7 +961,7 @@ func (svc *transactionsService) markTransactionSettled(tx *gorm.DB, dbTransactio
 		PaymentHash: dbTransaction.PaymentHash,
 		State:       constants.TRANSACTION_STATE_SETTLED,
 	}).RowsAffected > 0 {
-		logger.Logger.WithField("payment_hash", dbTransaction.PaymentHash).Error("payment already marked as sent")
+		logger.Logger.WithField("payment_hash", dbTransaction.PaymentHash).Debug("payment already marked as sent")
 		return &existingSettledTransaction, nil
 	}