From c54901e634c9744dc36c1e227d922f2089b37884 Mon Sep 17 00:00:00 2001
From: Pavel Zbitskiy <pavel@algorand.com>
Date: Mon, 27 Nov 2023 13:47:46 -0500
Subject: [PATCH] catchup: Fix empty cert if ledger already has a block

---
 catchup/catchpointService.go      | 6 ++++--
 catchup/catchpointService_test.go | 8 +++++---
 ledger/catchupaccessor.go         | 2 +-
 3 files changed, 10 insertions(+), 6 deletions(-)

diff --git a/catchup/catchpointService.go b/catchup/catchpointService.go
index a5175aff4c..e9b91266d6 100644
--- a/catchup/catchpointService.go
+++ b/catchup/catchpointService.go
@@ -373,8 +373,9 @@ func (cs *CatchpointCatchupService) processStageLatestBlockDownload() (err error
 	var blk *bookkeeping.Block
 	var cert *agreement.Certificate
 	// check to see if the current ledger might have this block. If so, we should try this first instead of downloading anything.
-	if ledgerBlock, err := cs.ledger.Block(blockRound); err == nil {
+	if ledgerBlock, ledgerCert, err := cs.ledger.BlockCert(blockRound); err == nil {
 		blk = &ledgerBlock
+		cert = &ledgerCert
 	}
 	var protoParams config.ConsensusParams
 	var ok bool
@@ -552,8 +553,9 @@ func (cs *CatchpointCatchupService) processStageBlocksDownload() (err error) {
 
 		blk = nil
 		// check to see if the current ledger might have this block. If so, we should try this first instead of downloading anything.
-		if ledgerBlock, err := cs.ledger.Block(topBlock.Round() - basics.Round(blocksFetched)); err == nil {
+		if ledgerBlock, ledgerCert, err := cs.ledger.BlockCert(topBlock.Round() - basics.Round(blocksFetched)); err == nil {
 			blk = &ledgerBlock
+			cert = &ledgerCert
 		} else {
 			switch err.(type) {
 			case ledgercore.ErrNoEntry:
diff --git a/catchup/catchpointService_test.go b/catchup/catchpointService_test.go
index 48cea110d7..dd8e469163 100644
--- a/catchup/catchpointService_test.go
+++ b/catchup/catchpointService_test.go
@@ -22,6 +22,7 @@ import (
 
 	"github.com/stretchr/testify/require"
 
+	"github.com/algorand/go-algorand/agreement"
 	"github.com/algorand/go-algorand/components/mocks"
 	"github.com/algorand/go-algorand/crypto"
 	"github.com/algorand/go-algorand/data/basics"
@@ -35,7 +36,7 @@ import (
 type catchpointCatchupLedger struct {
 }
 
-func (l *catchpointCatchupLedger) Block(rnd basics.Round) (blk bookkeeping.Block, err error) {
+func (l *catchpointCatchupLedger) BlockCert(rnd basics.Round) (blk bookkeeping.Block, cert agreement.Certificate, err error) {
 	blk = bookkeeping.Block{
 		BlockHeader: bookkeeping.BlockHeader{
 			UpgradeState: bookkeeping.UpgradeState{
@@ -43,13 +44,14 @@ func (l *catchpointCatchupLedger) Block(rnd basics.Round) (blk bookkeeping.Block
 			},
 		},
 	}
+	cert = agreement.Certificate{}
 	commitments, err := blk.PaysetCommit()
 	if err != nil {
-		return blk, err
+		return blk, cert, err
 	}
 	blk.TxnCommitments = commitments
 
-	return blk, nil
+	return blk, cert, nil
 }
 
 func (l *catchpointCatchupLedger) GenesisHash() (d crypto.Digest) {
diff --git a/ledger/catchupaccessor.go b/ledger/catchupaccessor.go
index 64ada07a08..3661c60057 100644
--- a/ledger/catchupaccessor.go
+++ b/ledger/catchupaccessor.go
@@ -238,7 +238,7 @@ const (
 
 // CatchupAccessorClientLedger represents ledger interface needed for catchpoint accessor clients
 type CatchupAccessorClientLedger interface {
-	Block(rnd basics.Round) (blk bookkeeping.Block, err error)
+	BlockCert(rnd basics.Round) (blk bookkeeping.Block, cert agreement.Certificate, err error)
 	GenesisHash() crypto.Digest
 	BlockHdr(rnd basics.Round) (blk bookkeeping.BlockHeader, err error)
 	Latest() (rnd basics.Round)