fix: use header_head to determine validators for forwarding transacti…

…ons (#10256)

Functions `find_chunk_producer_for_forwarding()`,
`find_validator_for_forwarding()` are not used much, one calls another,
and they both call `chain.head()`.

That seems unnecessary. Refactored to call `get_chunk_producer()`
directly, and not worry about 3 layers of functions using different
types of heads.

See #10251 for context

(cherry picked from commit 3a33ff5)

chain/chain/src/chain.rs

@@ -3703,25 +3703,6 @@ impl Chain {
         Ok(FinalExecutionOutcomeWithReceiptView { final_outcome, receipts })
     }
 
-    /// Find a validator to forward transactions to
-    pub fn find_chunk_producer_for_forwarding(
-        &self,
-        epoch_id: &EpochId,
-        shard_id: ShardId,
-        horizon: BlockHeight,
-    ) -> Result<AccountId, Error> {
-        let head = self.head()?;
-        let target_height = head.height + horizon - 1;
-        Ok(self.epoch_manager.get_chunk_producer(epoch_id, target_height, shard_id)?)
-    }
-
-    /// Find a validator that is responsible for a given shard to forward requests to
-    pub fn find_validator_for_forwarding(&self, shard_id: ShardId) -> Result<AccountId, Error> {
-        let head = self.head()?;
-        let epoch_id = self.epoch_manager.get_epoch_id_from_prev_block(&head.last_block_hash)?;
-        self.find_chunk_producer_for_forwarding(&epoch_id, shard_id, TX_ROUTING_HEIGHT_HORIZON)
-    }
-
     pub fn check_blocks_final_and_canonical(
         &self,
         block_headers: &[&BlockHeader],

chain/client/src/client.rs

@@ -1884,24 +1884,27 @@ impl Client {
     fn forward_tx(&self, epoch_id: &EpochId, tx: &SignedTransaction) -> Result<(), Error> {
         let shard_id =
             self.epoch_manager.account_id_to_shard_id(&tx.transaction.signer_id, epoch_id)?;
-        let head = self.chain.head()?;
+        // Use the header head to make sure the list of validators is as
+        // up-to-date as possible.
+        let head = self.chain.header_head()?;
         let maybe_next_epoch_id = self.get_next_epoch_id_if_at_boundary(&head)?;
 
         let mut validators = HashSet::new();
         for horizon in
             (2..=TX_ROUTING_HEIGHT_HORIZON).chain(vec![TX_ROUTING_HEIGHT_HORIZON * 2].into_iter())
         {
+            let target_height = head.height + horizon - 1;
             let validator =
-                self.chain.find_chunk_producer_for_forwarding(epoch_id, shard_id, horizon)?;
+                self.epoch_manager.get_chunk_producer(epoch_id, target_height, shard_id)?;
             validators.insert(validator);
             if let Some(next_epoch_id) = &maybe_next_epoch_id {
                 let next_shard_id = self
                     .epoch_manager
                     .account_id_to_shard_id(&tx.transaction.signer_id, next_epoch_id)?;
-                let validator = self.chain.find_chunk_producer_for_forwarding(
+                let validator = self.epoch_manager.get_chunk_producer(
                     next_epoch_id,
+                    target_height,
                     next_shard_id,
-                    horizon,
                 )?;
                 validators.insert(validator);
             }

chain/client/src/view_client.rs

@@ -11,6 +11,7 @@ use crate::{
 };
 use actix::{Actor, Addr, Handler, SyncArbiter, SyncContext};
 use near_async::messaging::CanSend;
+use near_chain::chain::TX_ROUTING_HEIGHT_HORIZON;
 use near_chain::types::{RuntimeAdapter, Tip};
 use near_chain::{
     get_epoch_block_producers_view, Chain, ChainGenesis, ChainStoreAccess, DoomslugThresholdMode,
@@ -475,7 +476,14 @@ impl ViewClientActor {
                     .epoch_manager
                     .account_id_to_shard_id(&signer_account_id, &head.epoch_id)
                     .map_err(|err| TxStatusError::InternalError(err.to_string()))?;
-                let validator = self.chain.find_validator_for_forwarding(target_shard_id)?;
+                let validator = self
+                    .epoch_manager
+                    .get_chunk_producer(
+                        &head.epoch_id,
+                        head.height + TX_ROUTING_HEIGHT_HORIZON - 1,
+                        target_shard_id,
+                    )
+                    .map_err(|err| TxStatusError::ChainError(err.into()))?;
 
                 self.network_adapter.send(PeerManagerMessageRequest::NetworkRequests(
                     NetworkRequests::TxStatus(validator, signer_account_id, tx_hash),