From 96da7ceb4fc9a2bd245d8ed804f516f284417482 Mon Sep 17 00:00:00 2001
From: Alex Vanin <alexey@nspcc.ru>
Date: Wed, 14 Jul 2021 12:43:59 +0300
Subject: [PATCH] [#697] governance: Make best effort traversing main chain
 list of keys

We should go through every key in main chain list to merget lists
as fast as possible. Previously we drop main chain traversing as
soon as we have no more new keys to add. Instead we should try
to go for old keys in the list and add it as more as we can.

Signed-off-by: Alex Vanin <alexey@nspcc.ru>
---
 pkg/innerring/processors/governance/list.go      | 13 +++++++++----
 pkg/innerring/processors/governance/list_test.go |  9 +++++++++
 2 files changed, 18 insertions(+), 4 deletions(-)

diff --git a/pkg/innerring/processors/governance/list.go b/pkg/innerring/processors/governance/list.go
index 6a76a0826..c85a764c2 100644
--- a/pkg/innerring/processors/governance/list.go
+++ b/pkg/innerring/processors/governance/list.go
@@ -44,19 +44,24 @@ func newAlphabetList(sidechain, mainnet keys.PublicKeys) (keys.PublicKeys, error
 	newNodes := 0
 	newNodeLimit := (ln - 1) / 3
 
-	for i := 0; i < ln; i++ {
-		if newNodes == newNodeLimit {
+	for _, node := range mainnet {
+		if len(result) == ln {
 			break
 		}
 
-		mainnetAddr := mainnet[i].Address()
+		limitReached := newNodes == newNodeLimit
+
+		mainnetAddr := node.Address()
 		if _, ok := hmap[mainnetAddr]; !ok {
+			if limitReached {
+				continue
+			}
 			newNodes++
 		} else {
 			hmap[mainnetAddr] = true
 		}
 
-		result = append(result, mainnet[i])
+		result = append(result, node)
 	}
 
 	if newNodes == 0 {
diff --git a/pkg/innerring/processors/governance/list_test.go b/pkg/innerring/processors/governance/list_test.go
index 3b4137204..e0121ab62 100644
--- a/pkg/innerring/processors/governance/list_test.go
+++ b/pkg/innerring/processors/governance/list_test.go
@@ -68,6 +68,15 @@ func TestNewAlphabetList(t *testing.T) {
 		require.NoError(t, err)
 		require.True(t, equalPublicKeyLists(exp, got)) // expect {1, 2, 4, 5}, not {1, 2, 3, 5}
 	})
+
+	t.Run("new keys in the middle", func(t *testing.T) {
+		orig := keys.PublicKeys{k[0], k[1], k[2], k[6], k[7], k[8], k[9]}
+		// `exp` should contain maximum amount of new keys (2) in the middle
+		exp := keys.PublicKeys{k[0], k[3], k[4], k[6], k[7], k[8], k[9]}
+		got, err := newAlphabetList(orig, exp)
+		require.NoError(t, err)
+		require.True(t, equalPublicKeyLists(exp, got))
+	})
 }
 
 func TestUpdateInnerRing(t *testing.T) {