From 3e2c47e89625a4d6354d822901013751d2ccab1e Mon Sep 17 00:00:00 2001
From: prathamesh0 <prathamesh.musale0@gmail.com>
Date: Thu, 7 Jul 2022 16:14:43 +0530
Subject: [PATCH] Avoid NULL result from canonical block hash query

---
 pkg/eth/backend.go                | 15 ++++++++++-----
 pkg/eth/cid_retriever.go          |  2 +-
 pkg/eth/test_helpers/test_data.go |  4 ++++
 3 files changed, 15 insertions(+), 6 deletions(-)

diff --git a/pkg/eth/backend.go b/pkg/eth/backend.go
index a5a8e34c..def93667 100644
--- a/pkg/eth/backend.go
+++ b/pkg/eth/backend.go
@@ -56,6 +56,7 @@ var (
 	errNegativeBlockNumber    = errors.New("negative block number not supported")
 	errHeaderHashNotFound     = errors.New("header for hash not found")
 	errHeaderNotFound         = errors.New("header not found")
+	errTxHashNotFound         = errors.New("transaction for hash not found")
 	errTxHashInMultipleBlocks = errors.New("transaction for hash found in more than one canonical block")
 
 	// errMissingSignature is returned if a block's extra-data section doesn't seem
@@ -63,8 +64,10 @@ var (
 )
 
 const (
-	RetrieveCanonicalBlockHashByNumber = `SELECT canonical_header_hash($1)`
-	RetrieveCanonicalHeaderByNumber    = `SELECT cid, data FROM eth.header_cids
+	RetrieveCanonicalBlockHashByNumber = `SELECT block_hash
+									FROM canonical_header_hash($1) AS block_hash
+									WHERE block_hash IS NOT NULL`
+	RetrieveCanonicalHeaderByNumber = `SELECT cid, data FROM eth.header_cids
 									INNER JOIN public.blocks ON (
 										header_cids.mh_key = blocks.key
 										AND header_cids.block_number = blocks.block_number
@@ -526,12 +529,14 @@ func (b *Backend) GetTransaction(ctx context.Context, txHash common.Hash) (*type
 		Index       uint64 `db:"index"`
 	}
 	var res = make([]txRes, 0)
-	if err := b.DB.Get(&res, RetrieveRPCTransaction, txHash.String()); err != nil {
+	if err := b.DB.Select(&res, RetrieveRPCTransaction, txHash.String()); err != nil {
 		return nil, common.Hash{}, 0, 0, err
 	}
 
-	// a transaction can be part of a only one canonical block
-	if len(res) > 1 {
+	if len(res) == 0 {
+		return nil, common.Hash{}, 0, 0, errTxHashNotFound
+	} else if len(res) > 1 {
+		// a transaction can be part of a only one canonical block
 		return nil, common.Hash{}, 0, 0, errTxHashInMultipleBlocks
 	}
 
diff --git a/pkg/eth/cid_retriever.go b/pkg/eth/cid_retriever.go
index 85e708c1..c1579638 100644
--- a/pkg/eth/cid_retriever.go
+++ b/pkg/eth/cid_retriever.go
@@ -737,7 +737,7 @@ func (ecr *CIDRetriever) RetrieveTxCIDByHash(txHash string) (TransactionCIDRecor
 
 	var txCID TransactionCIDRecord
 
-	err := ecr.gormDB.Joins("IPLD").First(&txCID, "tx_hash = ?", txHash).Error
+	err := ecr.gormDB.Joins("IPLD").Find(&txCID, "tx_hash = ? AND transaction_cids.header_id = (SELECT canonical_header_hash(transaction_cids.block_number))", txHash).Error
 	if err != nil {
 		log.Error("header cid retrieval error")
 		return txCID, err
diff --git a/pkg/eth/test_helpers/test_data.go b/pkg/eth/test_helpers/test_data.go
index 96d525d7..d4f7118d 100644
--- a/pkg/eth/test_helpers/test_data.go
+++ b/pkg/eth/test_helpers/test_data.go
@@ -301,6 +301,7 @@ var (
 	MockRctMetaPostPublish = []models.ReceiptModel{
 		{
 			BlockNumber:  "1",
+			HeaderID:     MockBlock.Hash().String(),
 			LeafCID:      Rct1CID.String(),
 			LeafMhKey:    Rct1MhKey,
 			Contract:     "",
@@ -308,6 +309,7 @@ var (
 		},
 		{
 			BlockNumber:  "1",
+			HeaderID:     MockBlock.Hash().String(),
 			LeafCID:      Rct2CID.String(),
 			LeafMhKey:    Rct2MhKey,
 			Contract:     "",
@@ -315,6 +317,7 @@ var (
 		},
 		{
 			BlockNumber:  "1",
+			HeaderID:     MockBlock.Hash().String(),
 			LeafCID:      Rct3CID.String(),
 			LeafMhKey:    Rct3MhKey,
 			Contract:     ContractAddress.String(),
@@ -322,6 +325,7 @@ var (
 		},
 		{
 			BlockNumber:  "1",
+			HeaderID:     MockBlock.Hash().String(),
 			LeafCID:      Rct4CID.String(),
 			LeafMhKey:    Rct4MhKey,
 			Contract:     "",