From 98cf62cc45d6edd8d35f326ba0736728e624d5fd Mon Sep 17 00:00:00 2001
From: stoffu <stoffu@protonmail.ch>
Date: Tue, 20 Mar 2018 11:09:58 +0900
Subject: [PATCH] hardfork: fix get_next_version()

---
 src/cryptonote_basic/hardfork.cpp |  6 +++---
 tests/unit_tests/hardfork.cpp     | 29 +++++++++++++++++++++++++++++
 2 files changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/cryptonote_basic/hardfork.cpp b/src/cryptonote_basic/hardfork.cpp
index aa6746304..f05b25901 100644
--- a/src/cryptonote_basic/hardfork.cpp
+++ b/src/cryptonote_basic/hardfork.cpp
@@ -394,9 +394,9 @@ uint8_t HardFork::get_next_version() const
 {
   CRITICAL_REGION_LOCAL(lock);
   uint64_t height = db.height();
-  for (unsigned int n = heights.size() - 1; n > 0; --n) {
-    if (height >= heights[n].height) {
-      return heights[n < heights.size() - 1 ? n + 1 : n].version;
+  for (auto i = heights.rbegin(); i != heights.rend(); ++i) {
+    if (height >= i->height) {
+      return (i == heights.rbegin() ? i : (i - 1))->version;
     }
   }
   return original_version;
diff --git a/tests/unit_tests/hardfork.cpp b/tests/unit_tests/hardfork.cpp
index ba3e95e7d..d33daca4c 100644
--- a/tests/unit_tests/hardfork.cpp
+++ b/tests/unit_tests/hardfork.cpp
@@ -256,6 +256,35 @@ TEST(check_for_height, Success)
   }
 }
 
+TEST(get, next_version)
+{
+  TestDB db;
+  HardFork hf(db);
+
+  ASSERT_TRUE(hf.add_fork(1, 0, 0));
+  ASSERT_TRUE(hf.add_fork(2, 5, 1));
+  ASSERT_TRUE(hf.add_fork(4, 10, 2));
+  hf.init();
+
+  for (uint64_t h = 0; h <= 4; ++h) {
+    ASSERT_EQ(2, hf.get_next_version());
+    db.add_block(mkblock(hf, h, 1), 0, 0, 0, crypto::hash());
+    ASSERT_TRUE(hf.add(db.get_block_from_height(h), h));
+  }
+
+  for (uint64_t h = 5; h <= 9; ++h) {
+    ASSERT_EQ(4, hf.get_next_version());
+    db.add_block(mkblock(hf, h, 2), 0, 0, 0, crypto::hash());
+    ASSERT_TRUE(hf.add(db.get_block_from_height(h), h));
+  }
+
+  for (uint64_t h = 10; h <= 15; ++h) {
+    ASSERT_EQ(4, hf.get_next_version());
+    db.add_block(mkblock(hf, h, 4), 0, 0, 0, crypto::hash());
+    ASSERT_TRUE(hf.add(db.get_block_from_height(h), h));
+  }
+}
+
 TEST(states, Success)
 {
   TestDB db;