hardfork: change window semantics to not count the newly added block

This allows knowing the hard fork a block must obey in order to be
added to the blockchain. The previous semantics would use that new
block's version vote to determine this hard fork, which made it
impossible to use the rules to validate transactions entering the
tx pool (and made it impossible to validate a block before adding
it to the blockchain).

1 files changed, 20 insertions, 5 deletions

diff --git a/src/cryptonote_core/hardfork.cpp b/src/cryptonote_core/hardfork.cpp
index d2e95b58e..f4df1f9c6 100644
--- a/src/cryptonote_core/hardfork.cpp
+++ b/src/cryptonote_core/hardfork.cpp
@@ -43,6 +43,10 @@ HardFork::HardFork(cryptonote::BlockchainDB &db, uint8_t original_version, time_
   window_size(window_size),
   threshold_percent(threshold_percent)
 {
+  if (window_size == 0)
+    throw "window_size needs to be strictly positive";
+  if (threshold_percent > 100)
+    throw "threshold_percent needs to be between 0 and 100";
 }
 
 bool HardFork::add(uint8_t version, uint64_t height, time_t time)
@@ -93,6 +97,8 @@ bool HardFork::add(const cryptonote::block &block, uint64_t height)
   if (!do_check(block))
     return false;
 
+  db.set_hard_fork_version(height, heights[current_fork_index].version);
+
   const uint8_t version = get_effective_version(block);
 
   while (versions.size() >= window_size) {
@@ -105,16 +111,15 @@ bool HardFork::add(const cryptonote::block &block, uint64_t height)
   last_versions[version]++;
   versions.push_back(version);
 
-  uint8_t voted = get_voted_fork_index(height);
+  uint8_t voted = get_voted_fork_index(height + 1);
   if (voted > current_fork_index) {
     for (int v = heights[current_fork_index].version + 1; v <= heights[voted].version; ++v) {
-      db.set_hard_fork_starting_height(v, height);
+      // we reached the vote threshold with this block, next one will be forked
+      db.set_hard_fork_starting_height(v, height + 1);
     }
     current_fork_index = voted;
   }
 
-  db.set_hard_fork_version(height, heights[current_fork_index].version);
-
   return true;
 }
 
@@ -159,7 +164,7 @@ bool HardFork::reorganize_from_block_height(uint64_t height)
 
   for (size_t n = 0; n < 256; ++n)
     last_versions[n] = 0;
-  const uint64_t rescan_height = height >= (window_size - 1) ? height - (window_size - 1) : 0;
+  const uint64_t rescan_height = height >= (window_size - 1) ? height - (window_size  -1) : 0;
   const uint8_t start_version = height == 0 ? original_version : db.get_hard_fork_version(height);
   while (heights[current_fork_index].version > start_version) {
     db.set_hard_fork_starting_height(heights[current_fork_index].version, std::numeric_limits<uint64_t>::max());
@@ -171,6 +176,16 @@ bool HardFork::reorganize_from_block_height(uint64_t height)
     last_versions[v]++;
     versions.push_back(v);
   }
+
+  uint8_t voted = get_voted_fork_index(height + 1);
+  if (voted > current_fork_index) {
+    for (int v = heights[current_fork_index].version + 1; v <= heights[voted].version; ++v) {
+      // we reached the vote threshold with this block, next one will be forked
+      db.set_hard_fork_starting_height(v, height + 1);
+    }
+    current_fork_index = voted;
+  }
+
   const uint64_t bc_height = db.height();
   for (uint64_t h = height + 1; h < bc_height; ++h) {
     add(db.get_block_from_height(h), h);