From 9ee8ffcca7b1be1d7836c09c5763334dc4e0481c Mon Sep 17 00:00:00 2001
From: Pieter Wuille <pieter.wuille@gmail.com>
Date: Sun, 12 May 2013 12:03:32 +0200
Subject: [PATCH] Check for correct genesis

At startup, check that the expected genesis is loaded. This should prevent
cases where accidentally a datadir from the wrong network is loaded
(testnet vs mainnet, e.g.).
---
 src/init.cpp | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/src/init.cpp b/src/init.cpp
index 767d7525a66..eb148745de9 100644
--- a/src/init.cpp
+++ b/src/init.cpp
@@ -864,6 +864,11 @@ bool AppInit2(boost::thread_group& threadGroup)
                     break;
                 }
 
+                // If the loaded chain has a wrong genesis, bail out immediately
+                // (we're likely using a testnet datadir, or the other way around).
+                if (!mapBlockIndex.empty() && pindexGenesisBlock == NULL)
+                    return InitError(_("Incorrect or no genesis block found. Wrong datadir for network?"));
+
                 // Initialize the block index (no-op if non-empty database was already loaded)
                 if (!InitBlockIndex()) {
                     strLoadError = _("Error initializing block database");