[Chore] Guard against nil buckets to prevent panics (#473)

* Guard against nil buckets to prevent panics

* Remove txindex check

bchrpc/server.go

@@ -2929,7 +2929,6 @@ func (s *GrpcServer) getSlpToken(hash *chainhash.Hash, vout uint32, scriptPubKey
 // NOTE: this is launched as a goroutine and does not return errors!
 //
 func (s *GrpcServer) slpEventHandler() {
-
 	if s.slpIndex == nil {
 		return
 	}

blockchain/indexers/addrindex.go

@@ -735,6 +735,9 @@ func (idx *AddrIndex) ConnectBlock(dbTx database.Tx, block *bchutil.Block,
 
 	// Add all of the index entries for each address.
 	addrIdxBucket := dbTx.Metadata().Bucket(addrIndexKey)
+	if addrIdxBucket == nil {
+		return fmt.Errorf("bucket nil for key: %s", addrIndexKey)
+	}
 	for addrKey, txIdxs := range addrsToTxns {
 		for _, txIdx := range txIdxs {
 			err := dbPutAddrIndexEntry(addrIdxBucket, addrKey,
@@ -762,6 +765,9 @@ func (idx *AddrIndex) DisconnectBlock(dbTx database.Tx, block *bchutil.Block,
 
 	// Remove all of the index entries for each address.
 	bucket := dbTx.Metadata().Bucket(addrIndexKey)
+	if bucket == nil {
+		return fmt.Errorf("bucket nil for key: %s", addrIndexKey)
+	}
 	for addrKey, txIdxs := range addrsToTxns {
 		err := dbRemoveAddrIndexEntries(bucket, addrKey, len(txIdxs))
 		if err != nil {
@@ -801,6 +807,9 @@ func (idx *AddrIndex) TxRegionsForAddress(dbTx database.Tx, addr bchutil.Address
 
 		var err error
 		addrIdxBucket := dbTx.Metadata().Bucket(addrIndexKey)
+		if addrIdxBucket == nil {
+			return fmt.Errorf("bucket nil for key: %s", addrIndexKey)
+		}
 		regions, skipped, err = dbFetchAddrIndexEntries(addrIdxBucket,
 			addrKey, numToSkip, numRequested, reverse,
 			fetchBlockHash)

blockchain/indexers/cfindex.go

@@ -7,6 +7,7 @@ package indexers
 import (
 	"encoding/binary"
 	"errors"
+	"fmt"
 
 	"github.com/gcash/bchd/blockchain"
 	"github.com/gcash/bchd/chaincfg"
@@ -66,25 +67,49 @@ var (
 // dbFetchFilterIdxEntry retrieves a data blob from the filter index database.
 // An entry's absence is not considered an error.
 func dbFetchFilterIdxEntry(dbTx database.Tx, key []byte, h *chainhash.Hash) ([]byte, error) {
-	idx := dbTx.Metadata().Bucket(cfIndexParentBucketKey).Bucket(key)
+	parentIdx := dbTx.Metadata().Bucket(cfIndexParentBucketKey)
+	if parentIdx == nil {
+		return []byte{}, fmt.Errorf("bucket nil for key: %s", cfIndexParentBucketKey)
+	}
+	idx := parentIdx.Bucket(key)
+	if idx == nil {
+		return []byte{}, fmt.Errorf("bucket nil for key: %s", key)
+	}
 	return idx.Get(h[:]), nil
 }
 
 // dbStoreFilterIdxEntry stores a data blob in the filter index database.
 func dbStoreFilterIdxEntry(dbTx database.Tx, key []byte, h *chainhash.Hash, f []byte) error {
-	idx := dbTx.Metadata().Bucket(cfIndexParentBucketKey).Bucket(key)
+	parentIdx := dbTx.Metadata().Bucket(cfIndexParentBucketKey)
+	if parentIdx == nil {
+		return fmt.Errorf("bucket nil for key: %s", cfIndexParentBucketKey)
+	}
+	idx := parentIdx.Bucket(key)
+	if idx == nil {
+		return fmt.Errorf("bucket nil for key: %s", key)
+	}
 	return idx.Put(h[:], f)
 }
 
 // dbDeleteFilterIdxEntry deletes a data blob from the filter index database.
 func dbDeleteFilterIdxEntry(dbTx database.Tx, key []byte, h *chainhash.Hash) error {
-	idx := dbTx.Metadata().Bucket(cfIndexParentBucketKey).Bucket(key)
+	parentIdx := dbTx.Metadata().Bucket(cfIndexParentBucketKey)
+	if parentIdx == nil {
+		return fmt.Errorf("bucket nil for key: %s", cfIndexParentBucketKey)
+	}
+	idx := parentIdx.Bucket(key)
+	if idx == nil {
+		return fmt.Errorf("bucket nil for key: %s", key)
+	}
 	return idx.Delete(h[:])
 }
 
 // dbFetchMigrationVersion retrieves the migration version from the bucket.
 func dbFetchMigrationVersion(dbTx database.Tx) (uint32, error) {
 	bucket := dbTx.Metadata().Bucket(cfIndexParentBucketKey)
+	if bucket == nil {
+		return 0, fmt.Errorf("bucket nil for key: %s", cfIndexParentBucketKey)
+	}
 	versionBytes := bucket.Get(cfIndexMigrationVersionKey)
 	version := uint32(0)
 	if len(versionBytes) == 4 {
@@ -96,6 +121,9 @@ func dbFetchMigrationVersion(dbTx database.Tx) (uint32, error) {
 // dbStoreMigrationVersion stores the migration version in the bucket.
 func dbStoreMigrationVersion(dbTx database.Tx, version uint32) error {
 	bucket := dbTx.Metadata().Bucket(cfIndexParentBucketKey)
+	if bucket == nil {
+		return fmt.Errorf("bucket nil for key: %s", cfIndexParentBucketKey)
+	}
 	versionBytes := make([]byte, 4)
 	binary.BigEndian.PutUint32(versionBytes, version)
 	return bucket.Put(cfIndexMigrationVersionKey, versionBytes)

blockchain/indexers/slpindex.go

@@ -166,6 +166,9 @@ func dbPutTokenIDIndexEntry(dbTx database.Tx, id uint32, metadata *TokenMetadata
 // token id for the provided hash from the index.
 func dbFetchTokenIDByHash(dbTx database.Tx, hash *chainhash.Hash) (uint32, error) {
 	hashIndex := dbTx.Metadata().Bucket(tokenIDByHashIndexBucketName)
+	if hashIndex == nil {
+		return 0, fmt.Errorf("bucket nil for key: %s", tokenIDByHashIndexBucketName)
+	}
 	serializedID := hashIndex.Get(hash[:])
 	if serializedID == nil {
 		return 0, errNoTokenIDHashEntry
@@ -177,6 +180,9 @@ func dbFetchTokenIDByHash(dbTx database.Tx, hash *chainhash.Hash) (uint32, error
 // retrieve the hash for the provided serialized token id from the index.
 func dbFetchTokenMetadataBySerializedID(dbTx database.Tx, serializedID []byte) (*TokenMetadata, error) {
 	idIndex := dbTx.Metadata().Bucket(tokenMetadataByIDIndexBucketName)
+	if idIndex == nil {
+		return nil, fmt.Errorf("bucket nil for key: %s", tokenMetadataByIDIndexBucketName)
+	}
 	serializedData := idIndex.Get(serializedID)
 	if serializedData == nil {
 		return nil, errNoTokenMetadataEntry
@@ -316,6 +322,9 @@ func dbPutSlpIndexEntry(idx *SlpIndex, dbTx database.Tx, entryInfo *dbSlpIndexEn
 	byteOrder.PutUint16(target[4:], uint16(entryInfo.slpMsg.TokenType()))
 	copy(target[6:], entryInfo.slpMsgPkScript)
 	slpIndex := dbTx.Metadata().Bucket(slpIndexKey)
+	if slpIndex == nil {
+		return fmt.Errorf("bucket nil for key: %s", slpIndexKey)
+	}
 	return slpIndex.Put(txHash[:], target)
 }
 
@@ -332,8 +341,11 @@ type SlpTxEntry struct {
 // nil will be returned for the both the entry and the error.
 func dbFetchSlpIndexEntry(dbTx database.Tx, txHash *chainhash.Hash) (*SlpTxEntry, error) {
 	// Load the record from the database and return now if it doesn't exist.
-	SlpIndex := dbTx.Metadata().Bucket(slpIndexKey)
-	serializedData := SlpIndex.Get(txHash[:])
+	slpIndex := dbTx.Metadata().Bucket(slpIndexKey)
+	if slpIndex == nil {
+		return nil, fmt.Errorf("bucket nil for key: %s", slpIndexKey)
+	}
+	serializedData := slpIndex.Get(txHash[:])
 	if len(serializedData) == 0 {
 		return nil, fmt.Errorf("slp entry does not exist %v", txHash)
 	}
@@ -376,6 +388,9 @@ func dbRemoveSlpIndexEntries(dbTx database.Tx, block *bchutil.Block) error {
 	// this method should only be called after a topological sort
 	dbRemoveSlpIndexEntry := func(dbTx database.Tx, txHash *chainhash.Hash) error {
 		slpIndex := dbTx.Metadata().Bucket(slpIndexKey)
+		if slpIndex == nil {
+			return fmt.Errorf("bucket nil for key: %s", slpIndexKey)
+		}
 		serializedData := slpIndex.Get(txHash[:])
 		if len(serializedData) == 0 {
 			return nil
@@ -1154,6 +1169,9 @@ func (idx *SlpIndex) buildGraphSearchTokenMap() (*map[chainhash.Hash]*chainhash.
 
 	err := idx.db.View(func(dbTx database.Tx) error {
 		idxBucket := dbTx.Metadata().Bucket(slpIndexKey)
+		if idxBucket == nil {
+			return fmt.Errorf("bucket nil for key: %s", slpIndexKey)
+		}
 
 		// loop through all of the valid slp txn items stored in the db
 		err := idxBucket.ForEach(func(k []byte, v []byte) error {

blockchain/indexers/txindex.go

@@ -134,6 +134,9 @@ func dbRemoveBlockIDIndexEntry(dbTx database.Tx, hash *chainhash.Hash) error {
 // block id for the provided hash from the index.
 func dbFetchBlockIDByHash(dbTx database.Tx, hash *chainhash.Hash) (uint32, error) {
 	hashIndex := dbTx.Metadata().Bucket(idByHashIndexBucketName)
+	if hashIndex == nil {
+		return 0, fmt.Errorf("bucket nil for key: %s", idByHashIndexBucketName)
+	}
 	serializedID := hashIndex.Get(hash[:])
 	if serializedID == nil {
 		return 0, errNoBlockIDEntry
@@ -146,6 +149,9 @@ func dbFetchBlockIDByHash(dbTx database.Tx, hash *chainhash.Hash) (uint32, error
 // retrieve the hash for the provided serialized block id from the index.
 func dbFetchBlockHashBySerializedID(dbTx database.Tx, serializedID []byte) (*chainhash.Hash, error) {
 	idIndex := dbTx.Metadata().Bucket(hashByIDIndexBucketName)
+	if idIndex == nil {
+		return nil, fmt.Errorf("bucket nil for key: %s", hashByIDIndexBucketName)
+	}
 	hashBytes := idIndex.Get(serializedID)
 	if hashBytes == nil {
 		return nil, errNoBlockIDEntry
@@ -179,6 +185,9 @@ func putTxIndexEntry(target []byte, blockID uint32, txLoc wire.TxLoc) {
 // been serialized putTxIndexEntry.
 func dbPutTxIndexEntry(dbTx database.Tx, txHash *chainhash.Hash, serializedData []byte) error {
 	txIndex := dbTx.Metadata().Bucket(txIndexKey)
+	if txIndex == nil {
+		return fmt.Errorf("bucket nil for key: %s", txIndexKey)
+	}
 	return txIndex.Put(txHash[:], serializedData)
 }
 
@@ -189,6 +198,9 @@ func dbPutTxIndexEntry(dbTx database.Tx, txHash *chainhash.Hash, serializedData
 func dbFetchTxIndexEntry(dbTx database.Tx, txHash *chainhash.Hash) (*database.BlockRegion, error) {
 	// Load the record from the database and return now if it doesn't exist.
 	txIndex := dbTx.Metadata().Bucket(txIndexKey)
+	if txIndex == nil {
+		return nil, fmt.Errorf("bucket nil for key: %s", txIndexKey)
+	}
 	serializedData := txIndex.Get(txHash[:])
 	if len(serializedData) == 0 {
 		return nil, nil
@@ -257,6 +269,9 @@ func dbAddTxIndexEntries(dbTx database.Tx, block *bchutil.Block, blockID uint32)
 // recent transaction index entry for the given hash.
 func dbRemoveTxIndexEntry(dbTx database.Tx, txHash *chainhash.Hash) error {
 	txIndex := dbTx.Metadata().Bucket(txIndexKey)
+	if txIndex == nil {
+		return fmt.Errorf("bucket nil for key: %s", txIndexKey)
+	}
 	serializedData := txIndex.Get(txHash[:])
 	if len(serializedData) == 0 {
 		return fmt.Errorf("can't remove non-existent transaction %s "+