From 047197e24c05438cc07f5b3928a680b7d6ba6a7f Mon Sep 17 00:00:00 2001
From: Mark Holt <135143369+mh0lt@users.noreply.github.com>
Date: Mon, 23 Oct 2023 15:17:55 +0100
Subject: [PATCH] Fix panic in isAgra check for txpool (#8562)

Fixes a nil pointer panic in the isagra check when running on an empty
chain db. In this case the block will return as nil with no error.
---
 erigon-lib/txpool/pool.go | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/erigon-lib/txpool/pool.go b/erigon-lib/txpool/pool.go
index 528c8425c..9111b5f4b 100644
--- a/erigon-lib/txpool/pool.go
+++ b/erigon-lib/txpool/pool.go
@@ -915,7 +915,7 @@ func (p *TxPool) isAgra() bool {
 	defer tx.Rollback()
 
 	head_block, err := chain.CurrentBlockNumber(tx)
-	if err != nil {
+	if head_block == nil || err != nil {
 		return false
 	}
 	// A new block is built on top of the head block, so when the head is agraBlock-1,