Update the best block when best proposal header is updated

In Tendermint best block needs precommits in the next
header. Currently, the best block is updated when the best proposal
header's previous block is imported. However, the best block is not
updated when a proposal block's next header is imported.

This commit updates best block when the next header is imported.

Author: majecty

core/src/client/importer.rs

@@ -318,6 +318,7 @@ impl Importer {
         _importer_lock: &MutexGuard<()>,
     ) -> usize {
         let prev_best_proposal_header_hash = client.block_chain().best_proposal_header().hash();
+        let prev_best_block_hash = client.block_chain().best_block_hash();
 
         let mut bad = HashSet::new();
         let mut imported = Vec::new();
@@ -350,7 +351,8 @@ impl Importer {
         self.header_queue.mark_as_bad(&bad.drain().collect::<Vec<_>>());
         let (enacted, retracted) = self.calculate_enacted_retracted(&routes);
 
-        let new_best_proposal_header_hash = client.block_chain().best_proposal_header().hash();
+        let new_best_proposal_header = client.block_chain().best_proposal_header();
+        let new_best_proposal_header_hash = new_best_proposal_header.hash();
         let best_proposal_header_changed = if prev_best_proposal_header_hash != new_best_proposal_header_hash {
             Some(new_best_proposal_header_hash)
         } else {
@@ -367,6 +369,14 @@ impl Importer {
             best_proposal_header_changed,
         );
 
+        let maybe_new_best_block_hash = new_best_proposal_header.parent_hash();
+        if best_proposal_header_changed.is_some()
+            && prev_best_block_hash != maybe_new_best_block_hash
+            && client.block(&BlockId::Hash(maybe_new_best_block_hash)).is_some()
+        {
+            client.update_best_as_committed(maybe_new_best_block_hash);
+        }
+
         client.db().flush().expect("DB flush failed.");
 
         imported.len()