From 3fd6269b781c52de71e5949cfce3068a884062fb Mon Sep 17 00:00:00 2001
From: Rob Mulholand <rmulholand@8thlight.com>
Date: Wed, 17 Apr 2019 16:10:58 -0500
Subject: [PATCH] Don't lookup transactions if no log events

- Prevents EOF error on transactions lookup
---
 libraries/shared/transactions/syncer.go      |  3 +++
 libraries/shared/transactions/syncer_test.go | 15 +++++++++++----
 pkg/geth/blockchain.go                       |  2 --
 3 files changed, 14 insertions(+), 6 deletions(-)

diff --git a/libraries/shared/transactions/syncer.go b/libraries/shared/transactions/syncer.go
index 8e043dd7..f8590e2b 100644
--- a/libraries/shared/transactions/syncer.go
+++ b/libraries/shared/transactions/syncer.go
@@ -28,6 +28,9 @@ func NewTransactionsSyncer(db *postgres.DB, blockChain core.BlockChain) Transact
 
 func (syncer TransactionsSyncer) SyncTransactions(headerID int64, logs []types.Log) error {
 	transactionHashes := getUniqueTransactionHashes(logs)
+	if len(transactionHashes) < 1 {
+		return nil
+	}
 	transactions, transactionErr := syncer.BlockChain.GetTransactions(transactionHashes)
 	if transactionErr != nil {
 		return transactionErr
diff --git a/libraries/shared/transactions/syncer_test.go b/libraries/shared/transactions/syncer_test.go
index 53df7817..f38f68d2 100644
--- a/libraries/shared/transactions/syncer_test.go
+++ b/libraries/shared/transactions/syncer_test.go
@@ -24,12 +24,19 @@ var _ = Describe("Transaction syncer", func() {
 	})
 
 	It("fetches transactions for logs", func() {
-		err := syncer.SyncTransactions(0, []types.Log{})
+		err := syncer.SyncTransactions(0, []types.Log{{TxHash: fakes.FakeHash}})
 
 		Expect(err).NotTo(HaveOccurred())
 		Expect(blockChain.GetTransactionsCalled).To(BeTrue())
 	})
 
+	It("does not fetch transactions if no logs", func() {
+		err := syncer.SyncTransactions(0, []types.Log{})
+
+		Expect(err).NotTo(HaveOccurred())
+		Expect(blockChain.GetTransactionsCalled).To(BeFalse())
+	})
+
 	It("only fetches transactions with unique hashes", func() {
 		err := syncer.SyncTransactions(0, []types.Log{{
 			TxHash: fakes.FakeHash,
@@ -44,7 +51,7 @@ var _ = Describe("Transaction syncer", func() {
 	It("returns error if fetching transactions fails", func() {
 		blockChain.GetTransactionsError = fakes.FakeError
 
-		err := syncer.SyncTransactions(0, []types.Log{})
+		err := syncer.SyncTransactions(0, []types.Log{{TxHash: fakes.FakeHash}})
 
 		Expect(err).To(HaveOccurred())
 		Expect(err).To(MatchError(fakes.FakeError))
@@ -55,7 +62,7 @@ var _ = Describe("Transaction syncer", func() {
 		mockHeaderRepository := fakes.NewMockHeaderRepository()
 		syncer.Repository = mockHeaderRepository
 
-		err := syncer.SyncTransactions(0, []types.Log{})
+		err := syncer.SyncTransactions(0, []types.Log{{TxHash: fakes.FakeHash}})
 
 		Expect(err).NotTo(HaveOccurred())
 		Expect(mockHeaderRepository.CreateTransactionsCalled).To(BeTrue())
@@ -67,7 +74,7 @@ var _ = Describe("Transaction syncer", func() {
 		mockHeaderRepository.CreateTransactionsError = fakes.FakeError
 		syncer.Repository = mockHeaderRepository
 
-		err := syncer.SyncTransactions(0, []types.Log{})
+		err := syncer.SyncTransactions(0, []types.Log{{TxHash: fakes.FakeHash}})
 
 		Expect(err).To(HaveOccurred())
 		Expect(err).To(MatchError(fakes.FakeError))
diff --git a/pkg/geth/blockchain.go b/pkg/geth/blockchain.go
index a2b641c7..5d2c156c 100644
--- a/pkg/geth/blockchain.go
+++ b/pkg/geth/blockchain.go
@@ -18,7 +18,6 @@ package geth
 
 import (
 	"errors"
-	"fmt"
 	"github.com/ethereum/go-ethereum"
 	"math/big"
 	"strconv"
@@ -122,7 +121,6 @@ func (blockChain *BlockChain) GetTransactions(transactionHashes []common.Hash) (
 
 	rpcErr := blockChain.rpcClient.BatchCall(batch)
 	if rpcErr != nil {
-		fmt.Println("rpc err")
 		return []core.TransactionModel{}, rpcErr
 	}