From 52e5c38aa5dcc01566bb6d05a5312b5b642899b4 Mon Sep 17 00:00:00 2001
From: Martin Holst Swende <martin@swende.se>
Date: Thu, 18 Feb 2021 09:05:47 +0100
Subject: [PATCH] core/state: copy the snap when copying the state (#22340)

* core/state: copy the snap when copying the state

* core/state: deep-copy snap stuff during state Copy
---
 core/state/statedb.go | 25 +++++++++++++++++++++++++
 1 file changed, 25 insertions(+)

diff --git a/core/state/statedb.go b/core/state/statedb.go
index 49f457a99f772..8fd066e24fecc 100644
--- a/core/state/statedb.go
+++ b/core/state/statedb.go
@@ -728,6 +728,31 @@ func (s *StateDB) Copy() *StateDB {
 	if s.prefetcher != nil {
 		state.prefetcher = s.prefetcher.copy()
 	}
+	if s.snaps != nil {
+		// In order for the miner to be able to use and make additions
+		// to the snapshot tree, we need to copy that aswell.
+		// Otherwise, any block mined by ourselves will cause gaps in the tree,
+		// and force the miner to operate trie-backed only
+		state.snaps = s.snaps
+		state.snap = s.snap
+		// deep copy needed
+		state.snapDestructs = make(map[common.Hash]struct{})
+		for k, v := range s.snapDestructs {
+			state.snapDestructs[k] = v
+		}
+		state.snapAccounts = make(map[common.Hash][]byte)
+		for k, v := range s.snapAccounts {
+			state.snapAccounts[k] = v
+		}
+		state.snapStorage = make(map[common.Hash]map[common.Hash][]byte)
+		for k, v := range s.snapStorage {
+			temp := make(map[common.Hash][]byte)
+			for kk, vv := range v {
+				temp[kk] = vv
+			}
+			state.snapStorage[k] = temp
+		}
+	}
 	return state
 }