node: Address PR comments

node/src/chain/acceptor.rs

@@ -494,7 +494,7 @@ impl<DB: database::DB, VM: vm::VMExecution, N: Network> Acceptor<N, DB, VM> {
     }
 
     /// Returns chain tip header
-    pub(crate) async fn header(&self) -> ledger::Header {
+    pub(crate) async fn tip_header(&self) -> ledger::Header {
         self.mrb.read().await.inner().header().clone()
     }
 
@@ -547,15 +547,14 @@ impl<DB: database::DB, VM: vm::VMExecution, N: Network> Acceptor<N, DB, VM> {
     }
 }
 
-/// Performs full verification of block header (blk_header) against
-/// local/current state.
+/// Performs full verification of block header against prev_block header where
+/// prev_block is usually the blockchain tip
 pub(crate) async fn verify_block_header<DB: database::DB>(
     db: Arc<RwLock<DB>>,
-    mrb: &ledger::Header,
+    prev_block: &ledger::Header,
     provisioners: &ContextProvisioners,
-    candidate_header: &ledger::Header,
+    header: &ledger::Header,
 ) -> anyhow::Result<bool> {
-    let validator = Validator::new(db, mrb, provisioners);
-
-    validator.execute_checks(candidate_header, false).await
+    let validator = Validator::new(db, prev_block, provisioners);
+    validator.execute_checks(header, false).await
 }

node/src/chain/fallback.rs

@@ -48,8 +48,8 @@ impl<'a, N: Network, DB: database::DB, VM: vm::VMExecution>
         self.acc.try_revert(revert_target).await
     }
 
-    /// Verifies if a block of header `local` can be replaced with a block with
-    /// header `remote`
+    /// Verifies if a block with header `local` can be replaced with a block
+    /// with header `remote`
     async fn verify_header(
         &self,
         local: &Header,
@@ -65,7 +65,7 @@ impl<'a, N: Network, DB: database::DB, VM: vm::VMExecution>
             (_, Ordering::Equal) => Err(anyhow!(
                 "iteration is equal to the current {:?}",
                 local.iteration
-            )),
+            )), // TODO: This may be a slashing condition
             _ => Ok(()),
         }?;
 

node/src/chain/fsm.rs

@@ -268,7 +268,7 @@ impl<DB: database::DB, VM: vm::VMExecution, N: Network> InSyncImpl<DB, VM, N> {
         msg: &Message,
     ) -> anyhow::Result<Option<(Block, SocketAddr)>> {
         let mut acc = self.acc.write().await;
-        let local_header = acc.header().await;
+        let local_header = acc.tip_header().await;
         let remote_height = remote_blk.header().height;
 
         if remote_height < local_header.height {
@@ -293,18 +293,18 @@ impl<DB: database::DB, VM: vm::VMExecution, N: Network> InSyncImpl<DB, VM, N> {
             }
 
             // If our local chain has a block L_B with ConsensusState not Final,
-            // and we receive a block N_B such that:
+            // and we receive a block R_B such that:
             //
-            // N_B.PrevBlock == L_B.PrevBlock
-            // N_B.Iteration < L_B.Iteration
+            // R_B.PrevBlock == L_B.PrevBlock
+            // R_B.Iteration < L_B.Iteration
             //
             // Then we fallback to N_B.PrevBlock and accept N_B
-            let header = acc.db.read().await.view(|t| {
+            let local_header = acc.db.read().await.view(|t| {
                 if let Some((prev_header, _)) =
                     t.fetch_block_header(&remote_blk.header().prev_block_hash)?
                 {
-                    let l_b_height = prev_header.height + 1;
-                    if let Some(l_b) = t.fetch_block_by_height(l_b_height)? {
+                    let local_height = prev_header.height + 1;
+                    if let Some(l_b) = t.fetch_block_by_height(local_height)? {
                         if remote_blk.header().iteration
                             < l_b.header().iteration
                         {
@@ -316,10 +316,10 @@ impl<DB: database::DB, VM: vm::VMExecution, N: Network> InSyncImpl<DB, VM, N> {
                 anyhow::Ok(None)
             })?;
 
-            if let Some(header) = header {
+            if let Some(local_header) = local_header {
                 match fallback::WithContext::new(acc.deref())
                     .try_revert(
-                        &header,
+                        &local_header,
                         remote_blk.header(),
                         RevertTarget::LastFinalizedState,
                     )
@@ -356,7 +356,7 @@ impl<DB: database::DB, VM: vm::VMExecution, N: Network> InSyncImpl<DB, VM, N> {
             info!(
                 event = "entering fallback",
                 height = local_header.height,
-                iter = local_header.height,
+                iter = local_header.iteration,
                 new_iter = remote_blk.header().iteration,
             );