From 0643b0d920a121ebc831143c5e6d7ade6b25c11b Mon Sep 17 00:00:00 2001
From: Ori Newman <orinewman1@gmail.com>
Date: Sun, 7 Oct 2018 16:44:29 +0300
Subject: [PATCH] [DEV-189] invert arguments order of daghash.Less (#83)

* [DEV-189] invert arguments order or daghash.Less

* [DEV-189] invert arguments order of daghash.Less in blockset.highest

* [DEV-189] change to equivalent condition in Hash.Less to make it prettier
---
 blockdag/blockset.go      | 6 +++---
 blockdag/phantom.go       | 2 +-
 blockdag/validate.go      | 2 +-
 dagconfig/daghash/hash.go | 4 ++--
 4 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/blockdag/blockset.go b/blockdag/blockset.go
index b6602e023..0d9042435 100644
--- a/blockdag/blockset.go
+++ b/blockdag/blockset.go
@@ -38,7 +38,7 @@ func (bs blockSet) maxHeight() int32 {
 func (bs blockSet) highest() *blockNode {
 	var highest *blockNode
 	for _, node := range bs {
-		if highest.height < node.height || daghash.Less(&highest.hash, &node.hash) {
+		if highest.height < node.height || daghash.Less(&node.hash, &highest.hash) {
 			highest = node
 		}
 	}
@@ -130,7 +130,7 @@ func (bs blockSet) hashes() []daghash.Hash {
 		hashes = append(hashes, hash)
 	}
 	sort.Slice(hashes, func(i, j int) bool {
-		return daghash.Less(&hashes[i], &hashes[j])
+		return daghash.Less(&hashes[j], &hashes[i])
 	})
 	return hashes
 }
@@ -160,7 +160,7 @@ func (bs blockSet) bluest() *blockNode {
 	for _, node := range bs {
 		if bluestNode == nil ||
 			node.blueScore > maxScore ||
-			(node.blueScore == maxScore && daghash.Less(&bluestNode.hash, &node.hash)) {
+			(node.blueScore == maxScore && daghash.Less(&node.hash, &bluestNode.hash)) {
 			bluestNode = node
 			maxScore = node.blueScore
 		}
diff --git a/blockdag/phantom.go b/blockdag/phantom.go
index ba7af226d..fe22cddbc 100644
--- a/blockdag/phantom.go
+++ b/blockdag/phantom.go
@@ -27,7 +27,7 @@ func phantom(block *blockNode, k uint32) (blues []*blockNode, selectedParent *bl
 		blues := traverseCandidates(block, candidates, parent)
 		score := uint64(len(blues)) + parent.blueScore
 
-		if score > bestScore || (score == bestScore && (bestHash == nil || daghash.Less(bestHash, &parent.hash))) {
+		if score > bestScore || (score == bestScore && (bestHash == nil || daghash.Less(&parent.hash, bestHash))) {
 			bestScore = score
 			bestBlues = blues
 			bestParent = parent
diff --git a/blockdag/validate.go b/blockdag/validate.go
index 20a68123a..795f3205d 100644
--- a/blockdag/validate.go
+++ b/blockdag/validate.go
@@ -435,7 +435,7 @@ func checkBlockParentsOrder(header *wire.BlockHeader) error {
 		sortedHashes = append(sortedHashes, hash)
 	}
 	sort.Slice(sortedHashes, func(i, j int) bool {
-		return daghash.Less(&sortedHashes[i], &sortedHashes[j])
+		return daghash.Less(&sortedHashes[j], &sortedHashes[i])
 	})
 	if !daghash.AreEqual(header.PrevBlocks, sortedHashes) {
 		return ruleError(ErrWrongParentsOrder, "block parents are not ordered by hash")
diff --git a/dagconfig/daghash/hash.go b/dagconfig/daghash/hash.go
index 9afac1721..86fcc5b6d 100644
--- a/dagconfig/daghash/hash.go
+++ b/dagconfig/daghash/hash.go
@@ -178,9 +178,9 @@ func (hash *Hash) Cmp(target *Hash) int {
 	return HashToBig(hash).Cmp(HashToBig(target))
 }
 
-//Less returns true iff hash b is less than hash a
+//Less returns true iff hash a is less than hash b
 func Less(a *Hash, b *Hash) bool {
-	return a.Cmp(b) > 0
+	return a.Cmp(b) < 0
 }
 
 //JoinHashesStrings joins all the stringified hashes separated by a separator