From 4e0d92a6ec7920d1347f92dda91ba4fa97740ba0 Mon Sep 17 00:00:00 2001
From: Sergey Vasilyev <swasilyev@gmail.com>
Date: Tue, 28 Apr 2020 01:12:21 +0300
Subject: [PATCH] Merkle tree fails to compute the root when there's no need in
 dummy nodes - fix

---
 crypto-primitives/src/merkle_tree/mod.rs | 18 ++++++++++--------
 1 file changed, 10 insertions(+), 8 deletions(-)

diff --git a/crypto-primitives/src/merkle_tree/mod.rs b/crypto-primitives/src/merkle_tree/mod.rs
index 366bd1a..1ea81b2 100644
--- a/crypto-primitives/src/merkle_tree/mod.rs
+++ b/crypto-primitives/src/merkle_tree/mod.rs
@@ -161,14 +161,16 @@ impl<P: MerkleTreeConfig> MerkleHashTree<P> {
         let mut cur_height = tree_height;
         let mut padding_tree = Vec::new();
         let mut cur_hash = tree[0].clone();
-        while cur_height < (Self::HEIGHT - 1) as usize {
-            cur_hash = hash_inner_node::<P::H>(&parameters, &cur_hash, &empty_hash, &mut buffer)?;
-            padding_tree.push((cur_hash.clone(), empty_hash.clone()));
-            cur_height += 1;
-        }
-
-        let root_hash = hash_inner_node::<P::H>(&parameters, &cur_hash, &empty_hash, &mut buffer)?;
-
+        let root_hash = if cur_height < Self::HEIGHT as usize {
+            while cur_height < (Self::HEIGHT - 1) as usize {
+                cur_hash = hash_inner_node::<P::H>(&parameters, &cur_hash, &empty_hash, &mut buffer)?;
+                padding_tree.push((cur_hash.clone(), empty_hash.clone()));
+                cur_height += 1;
+            }
+            hash_inner_node::<P::H>(&parameters, &cur_hash, &empty_hash, &mut buffer)?
+        } else {
+            cur_hash
+        };
         end_timer!(new_time);
 
         Ok(MerkleHashTree {