From 311d18ae92eedb3afd2aa552c3dfffbf378e656d Mon Sep 17 00:00:00 2001
From: Giulio rebuffo <giulio.rebuffo@gmail.com>
Date: Wed, 3 Aug 2022 02:49:06 +0200
Subject: [PATCH] better error (#4907)

Co-authored-by: giuliorebuffo <giuliorebuffo@system76-pc.localdomain>
---
 core/genesis.go | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/core/genesis.go b/core/genesis.go
index eb424e16e..c737308de 100644
--- a/core/genesis.go
+++ b/core/genesis.go
@@ -156,7 +156,11 @@ type GenesisMismatchError struct {
 }
 
 func (e *GenesisMismatchError) Error() string {
-	return fmt.Sprintf("database contains incompatible genesis (have %x, new %x)", e.Stored, e.New)
+	config := params.ChainConfigByGenesisHash(e.Stored)
+	if config == nil {
+		return fmt.Sprintf("database contains incompatible genesis (have %x, new %x)", e.Stored, e.New)
+	}
+	return fmt.Sprintf("database contains incompatible genesis (try with --chain=%s)", config.ChainName)
 }
 
 // CommitGenesisBlock writes or updates the genesis block in db.