From aee88cf4e5e68208bbe327b43ed1a678ad5ad356 Mon Sep 17 00:00:00 2001
From: Jordan Krage <jmank88@gmail.com>
Date: Sun, 15 Jul 2018 09:29:10 -0500
Subject: [PATCH] core: check txn length when building a transaction set

---
 core/types/transaction.go | 14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)

diff --git a/core/types/transaction.go b/core/types/transaction.go
index 82af9335ff..76ca331f8c 100644
--- a/core/types/transaction.go
+++ b/core/types/transaction.go
@@ -331,12 +331,14 @@ func NewTransactionsByPriceAndNonce(signer Signer, txs map[common.Address]Transa
 	// Initialize a price based heap with the head transactions
 	heads := make(TxByPrice, 0, len(txs))
 	for from, accTxs := range txs {
-		heads = append(heads, accTxs[0])
-		// Ensure the sender address is from the signer
-		acc, _ := Sender(signer, accTxs[0])
-		txs[acc] = accTxs[1:]
-		if from != acc {
-			delete(txs, from)
+		if len(accTxs) > 0 {
+			heads = append(heads, accTxs[0])
+			// Ensure the sender address is from the signer
+			acc, _ := Sender(signer, accTxs[0])
+			txs[acc] = accTxs[1:]
+			if from != acc {
+				delete(txs, from)
+			}
 		}
 	}
 	heap.Init(&heads)