From 18c8ded42c76e2fd07531bb7cb30ca75b0f9fe5f Mon Sep 17 00:00:00 2001
From: Felix Lange <fjl@twurst.com>
Date: Sat, 15 Oct 2016 00:40:32 +0200
Subject: [PATCH] [release/1.4.18] trie: fix regression that linked all
 downloaded nodes together

The trie sync code links subtries using pointers into node structs.
Since commit 40cdcf1183 nodes are no longer copied when unpacking from
an interface value, causing all nodes to get linked up as the sync
progresses. Fix it by breaking the pointer chain with an explicit copy.

(cherry picked from commit 2cd7a0395dd8813867884bced1b01663165ea1d4)
---
 trie/sync.go | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/trie/sync.go b/trie/sync.go
index 3de758536..400dff903 100644
--- a/trie/sync.go
+++ b/trie/sync.go
@@ -213,11 +213,13 @@ func (s *TrieSync) children(req *request) ([]*request, error) {
 
 	switch node := (*req.object).(type) {
 	case *shortNode:
+		node = node.copy() // Prevents linking all downloaded nodes together.
 		children = []child{{
 			node:  &node.Val,
 			depth: req.depth + len(node.Key),
 		}}
 	case *fullNode:
+		node = node.copy()
 		for i := 0; i < 17; i++ {
 			if node.Children[i] != nil {
 				children = append(children, child{