Update get recent blockhashes to return confirmed blockhashes only

core/src/replay_stage.rs

@@ -299,12 +299,13 @@ impl ReplayStage {
     ) where
         T: 'static + KeypairUtil + Send + Sync,
     {
+        if let Some(new_root) = locktower.record_vote(bank.slot()) {
+            bank_forks.write().unwrap().set_root(new_root);
+            blocktree.set_root(new_root);
+            Self::handle_new_root(&bank_forks, progress);
+        }
+        locktower.update_epoch(&bank);
         if let Some(ref voting_keypair) = voting_keypair {
-            if let Some(new_root) = locktower.record_vote(bank.slot()) {
-                bank_forks.write().unwrap().set_root(new_root);
-                blocktree.set_root(new_root);
-                Self::handle_new_root(&bank_forks, progress);
-            }
             // Send our last few votes along with the new one
             let vote_ix = vote_instruction::vote(vote_account_pubkey, locktower.recent_votes());
             let vote_tx = Transaction::new_signed_instructions(
@@ -312,7 +313,6 @@ impl ReplayStage {
                 vec![vote_ix],
                 bank.last_blockhash(),
             );
-            locktower.update_epoch(&bank);
             cluster_info.write().unwrap().push_vote(vote_tx);
         }
     }

core/src/rpc.rs

@@ -74,7 +74,7 @@ impl JsonRpcRequestProcessor {
     }
 
     fn get_recent_blockhash(&self) -> String {
-        let id = self.bank().last_blockhash();
+        let id = self.bank().get_confirmed_blockhash();
         bs58::encode(id).into_string()
     }
 
@@ -329,7 +329,7 @@ impl RpcSol for RpcSolImpl {
             .read()
             .unwrap()
             .bank()
-            .last_blockhash();
+            .get_confirmed_blockhash();
         let transaction = request_airdrop_transaction(&drone_addr, &pubkey, lamports, blockhash)
             .map_err(|err| {
                 info!("request_airdrop_transaction failed: {:?}", err);
@@ -450,7 +450,7 @@ mod tests {
         let bank = bank_forks.read().unwrap().working_bank();
         let exit = Arc::new(AtomicBool::new(false));
 
-        let blockhash = bank.last_blockhash();
+        let blockhash = bank.get_confirmed_blockhash();
         let tx = system_transaction::transfer(&alice, pubkey, 20, blockhash, 0);
         bank.process_transaction(&tx).expect("process transaction");
 
@@ -493,7 +493,7 @@ mod tests {
             &exit,
         );
         thread::spawn(move || {
-            let blockhash = bank.last_blockhash();
+            let blockhash = bank.get_confirmed_blockhash();
             let tx = system_transaction::transfer(&alice, &bob_pubkey, 20, blockhash, 0);
             bank.process_transaction(&tx).expect("process transaction");
         })

runtime/src/bank.rs

@@ -382,6 +382,14 @@ impl Bank {
     pub fn last_blockhash(&self) -> Hash {
         self.blockhash_queue.read().unwrap().last_hash()
     }
+    /// Return the root bank's blockhash
+    pub fn get_confirmed_blockhash(&self) -> Hash {
+        if let Some(bank) = self.parents().last() {
+            bank.last_blockhash()
+        } else {
+            self.last_blockhash()
+        }
+    }
 
     /// Forget all signatures. Useful for benchmarking.
     pub fn clear_signatures(&self) {