Fix issue in polling for transaction signatures (#4923)

- Specifically if multiple confirmation for the signature is requested

client/src/rpc_client.rs

@@ -443,10 +443,9 @@ impl RpcClient {
         &self,
         signature: &Signature,
         min_confirmed_blocks: usize,
-    ) -> io::Result<()> {
+    ) -> io::Result<usize> {
         let mut now = Instant::now();
         let mut confirmed_blocks = 0;
-        let mut wait_time = 15;
         loop {
             let response = self.get_num_blocks_since_signature_confirmation(signature);
             match response {
@@ -461,12 +460,6 @@ impl RpcClient {
                         );
                         now = Instant::now();
                         confirmed_blocks = count;
-                        // If the signature has been confirmed once, wait extra while reconfirming it
-                        // One confirmation means the transaction has been seen by the network, so
-                        // next confirmation (for a higher block count) should come through.
-                        // Returning an error prematurely will cause a valid transaction to be deemed
-                        // as failure.
-                        wait_time = 30;
                     }
                     if count >= min_confirmed_blocks {
                         break;
@@ -476,7 +469,7 @@ impl RpcClient {
                     debug!("check_confirmations request failed: {:?}", err);
                 }
             };
-            if now.elapsed().as_secs() > wait_time {
+            if now.elapsed().as_secs() > 15 {
                 info!(
                     "signature {} confirmed {} out of {} failed after {} ms",
                     signature,
@@ -484,12 +477,16 @@ impl RpcClient {
                     min_confirmed_blocks,
                     now.elapsed().as_millis()
                 );
-                // TODO: Return a better error.
-                return Err(io::Error::new(io::ErrorKind::Other, "signature not found"));
+                if confirmed_blocks > 0 {
+                    return Ok(confirmed_blocks);
+                } else {
+                    // TODO: Return a better error.
+                    return Err(io::Error::new(io::ErrorKind::Other, "signature not found"));
+                }
             }
             sleep(Duration::from_secs(1));
         }
-        Ok(())
+        Ok(confirmed_blocks)
     }
 
     pub fn get_num_blocks_since_signature_confirmation(

client/src/thin_client.rs

@@ -203,26 +203,38 @@ impl ThinClient {
         keypairs: &[&Keypair],
         transaction: &mut Transaction,
         tries: usize,
-        min_confirmed_blocks: usize,
+        pending_confirmations: usize,
     ) -> io::Result<Signature> {
         for x in 0..tries {
             let now = Instant::now();
             let mut buf = vec![0; serialized_size(&transaction).unwrap() as usize];
             let mut wr = std::io::Cursor::new(&mut buf[..]);
+            let mut num_confirmed = 0;
+            let mut wait_time = MAX_PROCESSING_AGE;
             serialize_into(&mut wr, &transaction)
                 .expect("serialize Transaction in pub fn transfer_signed");
             // resend the same transaction until the transaction has no chance of succeeding
-            while now.elapsed().as_secs() < MAX_PROCESSING_AGE as u64 {
-                self.transactions_socket
-                    .send_to(&buf[..], &self.transactions_addr())?;
-                if self
-                    .poll_for_signature_confirmation(
-                        &transaction.signatures[0],
-                        min_confirmed_blocks,
-                    )
-                    .is_ok()
-                {
-                    return Ok(transaction.signatures[0]);
+            while now.elapsed().as_secs() < wait_time as u64 {
+                if num_confirmed == 0 {
+                    // Send the transaction if there has been no confirmation (e.g. the first time)
+                    self.transactions_socket
+                        .send_to(&buf[..], &self.transactions_addr())?;
+                }
+
+                if let Ok(confirmed_blocks) = self.poll_for_signature_confirmation(
+                    &transaction.signatures[0],
+                    pending_confirmations,
+                ) {
+                    num_confirmed = confirmed_blocks;
+                    if confirmed_blocks >= pending_confirmations {
+                        return Ok(transaction.signatures[0]);
+                    }
+                    // Since network has seen the transaction, wait longer to receive
+                    // all pending confirmations. Resending the transaction could result into
+                    // extra transaction fees
+                    wait_time = wait_time.max(
+                        MAX_PROCESSING_AGE * pending_confirmations.saturating_sub(num_confirmed),
+                    );
                 }
             }
             info!(
@@ -385,7 +397,7 @@ impl SyncClient for ThinClient {
         &self,
         signature: &Signature,
         min_confirmed_blocks: usize,
-    ) -> TransportResult<()> {
+    ) -> TransportResult<usize> {
         Ok(self
             .rpc_client()
             .poll_for_signature_confirmation(signature, min_confirmed_blocks)?)

runtime/src/bank_client.rs

@@ -127,7 +127,7 @@ impl SyncClient for BankClient {
         &self,
         signature: &Signature,
         min_confirmed_blocks: usize,
-    ) -> Result<()> {
+    ) -> Result<usize> {
         let mut now = Instant::now();
         let mut confirmed_blocks = 0;
         loop {
@@ -152,7 +152,7 @@ impl SyncClient for BankClient {
             }
             sleep(Duration::from_millis(250));
         }
-        Ok(())
+        Ok(confirmed_blocks)
     }
 
     fn poll_for_signature(&self, signature: &Signature) -> Result<()> {

sdk/src/client.rs

@@ -64,7 +64,7 @@ pub trait SyncClient {
         &self,
         signature: &Signature,
         min_confirmed_blocks: usize,
-    ) -> Result<()>;
+    ) -> Result<usize>;
 
     /// Poll to confirm a transaction.
     fn poll_for_signature(&self, signature: &Signature) -> Result<()>;