From c46aae23daf0a1a172e08f97dcf2d7159e33eae5 Mon Sep 17 00:00:00 2001
From: Evgeny Danilenko <6655321@bk.ru>
Date: Thu, 9 Feb 2023 11:07:44 +0400
Subject: [PATCH] add check for empty lists in txpool (#704)

* add check

* linters
---
 core/tx_list.go | 8 ++++++--
 core/tx_pool.go | 5 ++++-
 2 files changed, 10 insertions(+), 3 deletions(-)

diff --git a/core/tx_list.go b/core/tx_list.go
index e763777e33..fea4434b9b 100644
--- a/core/tx_list.go
+++ b/core/tx_list.go
@@ -351,9 +351,8 @@ func (m *txSortedMap) lastElement() *types.Transaction {
 
 		m.cacheMu.Unlock()
 
-		cache = make(types.Transactions, 0, len(m.items))
-
 		m.m.RLock()
+		cache = make(types.Transactions, 0, len(m.items))
 
 		for _, tx := range m.items {
 			cache = append(cache, tx)
@@ -373,6 +372,11 @@ func (m *txSortedMap) lastElement() *types.Transaction {
 		hitCacheCounter.Inc(1)
 	}
 
+	ln := len(cache)
+	if ln == 0 {
+		return nil
+	}
+
 	return cache[len(cache)-1]
 }
 
diff --git a/core/tx_pool.go b/core/tx_pool.go
index e98fd2e0ae..a3a10e7023 100644
--- a/core/tx_pool.go
+++ b/core/tx_pool.go
@@ -1539,6 +1539,7 @@ func (pool *TxPool) runReorg(ctx context.Context, done chan struct{}, reset *txp
 		// remove any transaction that has been included in the block or was invalidated
 		// because of another transaction (e.g. higher gas price).
 
+		//nolint:nestif
 		if reset != nil {
 			tracing.ElapsedTime(ctx, span, "new block", func(_ context.Context, innerSpan trace.Span) {
 
@@ -1573,7 +1574,9 @@ func (pool *TxPool) runReorg(ctx context.Context, done chan struct{}, reset *txp
 				tracing.ElapsedTime(ctx, innerSpan, "09 fill nonces", func(_ context.Context, innerSpan trace.Span) {
 					for addr, list := range pool.pending {
 						highestPending = list.LastElement()
-						nonces[addr] = highestPending.Nonce() + 1
+						if highestPending != nil {
+							nonces[addr] = highestPending.Nonce() + 1
+						}
 					}
 				})