multi: update database error types.

This updates the database error types to leverage
go 1.13 errors.Is/As functionality as well as confirm
to the error infrastructure best practices.

blockchain/chainio.go

@@ -793,12 +793,9 @@ func dbFetchSpendJournalEntry(dbTx database.Tx, block *dcrutil.Block) ([]spentTx
 		// Ensure any deserialization errors are returned as database
 		// corruption errors.
 		if isDeserializeErr(err) {
-			return nil, database.Error{
-				ErrorCode: database.ErrCorruption,
-				Description: fmt.Sprintf("corrupt spend "+
-					"information for %v: %v", block.Hash(),
-					err),
-			}
+			str := fmt.Sprintf("corrupt spend information for %v: %v",
+				block.Hash(), err)
+			return nil, database.MakeError(database.ErrCorruption, str)
 		}
 
 		return nil, err
@@ -1164,11 +1161,8 @@ func dbFetchUtxoEntry(dbTx database.Tx, hash *chainhash.Hash) (*UtxoEntry, error
 		// Ensure any deserialization errors are returned as database
 		// corruption errors.
 		if isDeserializeErr(err) {
-			return nil, database.Error{
-				ErrorCode: database.ErrCorruption,
-				Description: fmt.Sprintf("corrupt utxo entry "+
-					"for %v: %v", hash, err),
-			}
+			str := fmt.Sprintf("corrupt utxo entry for %v: %v", hash, err)
+			return nil, database.MakeError(database.ErrCorruption, str)
 		}
 
 		return nil, err
@@ -1211,11 +1205,8 @@ func dbFetchUtxoStats(dbTx database.Tx) (*UtxoStats, error) {
 			// Ensure any deserialization errors are returned as database
 			// corruption errors.
 			if isDeserializeErr(err) {
-				return nil, database.Error{
-					ErrorCode: database.ErrCorruption,
-					Description: fmt.Sprintf("corrupt utxo entry "+
-						"for %v: %v", hash, err),
-				}
+				str := fmt.Sprintf("corrupt utxo entry for %v: %v", hash, err)
+				return nil, database.MakeError(database.ErrCorruption, str)
 			}
 
 			return nil, err
@@ -1312,11 +1303,8 @@ func dbFetchGCSFilter(dbTx database.Tx, blockHash *chainhash.Hash) (*gcs.FilterV
 
 	filter, err := gcs.FromBytesV2(blockcf2.B, blockcf2.M, serialized)
 	if err != nil {
-		return nil, database.Error{
-			ErrorCode: database.ErrCorruption,
-			Description: fmt.Sprintf("corrupt filter for %v: %v", blockHash,
-				err),
-		}
+		str := fmt.Sprintf("corrupt filter for %v: %v", blockHash, err)
+		return nil, database.MakeError(database.ErrCorruption, str)
 	}
 
 	return filter, nil
@@ -1511,11 +1499,9 @@ func deserializeBestChainState(serializedData []byte) (bestChainState, error) {
 	// and work sum length.
 	expectedMinLen := chainhash.HashSize + 4 + 8 + 8 + 4
 	if len(serializedData) < expectedMinLen {
-		return bestChainState{}, database.Error{
-			ErrorCode: database.ErrCorruption,
-			Description: fmt.Sprintf("corrupt best chain state size; min %v "+
-				"got %v", expectedMinLen, len(serializedData)),
-		}
+		str := fmt.Sprintf("corrupt best chain state size; min %v got %v",
+			expectedMinLen, len(serializedData))
+		return bestChainState{}, database.MakeError(database.ErrCorruption, str)
 	}
 
 	state := bestChainState{}
@@ -1536,11 +1522,9 @@ func deserializeBestChainState(serializedData []byte) (bestChainState, error) {
 	// Ensure the serialized data has enough bytes to deserialize the work
 	// sum.
 	if uint32(len(serializedData[offset:])) < workSumBytesLen {
-		return bestChainState{}, database.Error{
-			ErrorCode: database.ErrCorruption,
-			Description: fmt.Sprintf("corrupt work sum size; want %v "+
-				"got %v", workSumBytesLen, uint32(len(serializedData[offset:]))),
-		}
+		str := fmt.Sprintf("corrupt work sum size; want %v got %v",
+			workSumBytesLen, uint32(len(serializedData[offset:])))
+		return bestChainState{}, database.MakeError(database.ErrCorruption, str)
 	}
 	workSumBytes := serializedData[offset : offset+workSumBytesLen]
 	state.workSum = new(big.Int).SetBytes(workSumBytes)

blockchain/chainio_test.go

@@ -1470,44 +1470,39 @@ func TestBestChainStateDeserializeErrors(t *testing.T) {
 	tests := []struct {
 		name       string
 		serialized []byte
-		errType    error
+		errKind    database.ErrorKind
 	}{
 		{
 			name:       "nothing serialized",
 			serialized: hexToBytes(""),
-			errType:    database.Error{ErrorCode: database.ErrCorruption},
+			errKind:    database.ErrCorruption,
 		},
 		{
 			name:       "short data in hash",
 			serialized: hexToBytes("0000"),
-			errType:    database.Error{ErrorCode: database.ErrCorruption},
+			errKind:    database.ErrCorruption,
 		},
 		{
 			name:       "short data in work sum",
 			serialized: hexToBytes("6fe28c0ab6f1b372c1a6a246ae63f74f931e8365e15a089c68d61900000000000000000001000000000000000500000001000100"),
-			errType:    database.Error{ErrorCode: database.ErrCorruption},
+			errKind:    database.ErrCorruption,
 		},
 	}
 
 	for _, test := range tests {
 		// Ensure the expected error type and code is returned.
 		_, err := deserializeBestChainState(test.serialized)
-		if !errors.As(err, &test.errType) {
+		var derr database.Error
+		if !errors.As(err, &derr) {
 			t.Errorf("deserializeBestChainState (%s): expected "+
 				"error type does not match - got %T, want %T",
-				test.name, err, test.errType)
+				test.name, err, test.errKind)
 			continue
 		}
-		var derr database.Error
-		if errors.As(err, &derr) {
-			var tderr database.Error
-			if !errors.As(test.errType, &tderr) || derr.ErrorCode != tderr.ErrorCode {
-				t.Errorf("deserializeBestChainState (%s): "+
-					"wrong  error code got: %v, want: %v",
-					test.name, derr.ErrorCode,
-					tderr.ErrorCode)
-				continue
-			}
+		if !errors.Is(derr, test.errKind) {
+			t.Errorf("deserializeBestChainState (%s): wrong error code "+
+				"got: %v, want: %v", test.name, derr, test.errKind)
+			continue
 		}
 	}
 }

blockchain/go.mod

@@ -21,6 +21,7 @@ replace (
 	github.com/decred/dcrd/blockchain/stake/v3 => ./stake
 	github.com/decred/dcrd/blockchain/standalone/v2 => ./standalone
 	github.com/decred/dcrd/chaincfg/v3 => ../chaincfg
+	github.com/decred/dcrd/database/v2 => ../database
 	github.com/decred/dcrd/dcrec/secp256k1/v3 => ../dcrec/secp256k1
 	github.com/decred/dcrd/dcrutil/v3 => ../dcrutil
 	github.com/decred/dcrd/txscript/v3 => ../txscript

blockchain/go.sum

@@ -1,9 +1,5 @@
 github.com/agl/ed25519 v0.0.0-20170116200512-5312a6153412 h1:w1UutsfOrms1J05zt7ISrnJIXKzwaspym5BTKGx93EI=
 github.com/agl/ed25519 v0.0.0-20170116200512-5312a6153412/go.mod h1:WPjqKcmVOxf0XSf3YxCJs6N6AOSrOx3obionmG7T0y0=
-github.com/btcsuite/goleveldb v1.0.0 h1:Tvd0BfvqX9o823q1j2UZ/epQo09eJh6dTcRp79ilIN4=
-github.com/btcsuite/goleveldb v1.0.0/go.mod h1:QiK9vBlgftBg6rWQIj6wFzbPfRjiykIEhBH4obrXJ/I=
-github.com/btcsuite/snappy-go v1.0.0 h1:ZxaA6lo2EpxGddsA8JwWOcxlzRybb444sgmeJQMJGQE=
-github.com/btcsuite/snappy-go v1.0.0/go.mod h1:8woku9dyThutzjeg+3xrA5iCpBRH8XEEg3lh6TiUghc=
 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/dchest/siphash v1.2.1 h1:4cLinnzVJDKxTCl9B01807Yiy+W7ZzVHj/KIroQRvT4=
@@ -22,8 +18,6 @@ github.com/decred/dcrd/crypto/blake256 v1.0.0 h1:/8DMNYp9SGi5f0w7uCm6d6M4OU2rGFK
 github.com/decred/dcrd/crypto/blake256 v1.0.0/go.mod h1:sQl2p6Y26YV+ZOcSTP6thNdn47hh8kt6rqSlvmrXFAc=
 github.com/decred/dcrd/crypto/ripemd160 v1.0.0 h1:MciTnR4NfBqDFRFjFkrn8WPLP4Vo7t6ww6ghfn6wcXQ=
 github.com/decred/dcrd/crypto/ripemd160 v1.0.0/go.mod h1:F0H8cjIuWTRoixr/LM3REB8obcWkmYx0gbxpQWR8RPg=
-github.com/decred/dcrd/database/v2 v2.0.1 h1:ghLzkKpVpwvjrdRv3njrEfkvygQpYQX66sGVs8ha+E8=
-github.com/decred/dcrd/database/v2 v2.0.1/go.mod h1:ZOaWTv3IlNqCA+y7q3q5EozgmiDOmNwCSq3ntZn2CDo=
 github.com/decred/dcrd/dcrec v1.0.0 h1:W+z6Es+Rai3MXYVoPAxYr5U1DGis0Co33scJ6uH2J6o=
 github.com/decred/dcrd/dcrec v1.0.0/go.mod h1:HIaqbEJQ+PDzQcORxnqen5/V1FR3B4VpIfmePklt8Q8=
 github.com/decred/dcrd/dcrec/edwards/v2 v2.0.0 h1:E5KszxGgpjpmW8vN811G6rBAZg0/S/DftdGqN4FW5x4=
@@ -42,21 +36,34 @@ github.com/decred/slog v1.0.0 h1:Dl+W8O6/JH6n2xIFN2p3DNjCmjYwvrXsjlSJTQQ4MhE=
 github.com/decred/slog v1.0.0/go.mod h1:zR98rEZHSnbZ4WHZtO0iqmSZjDLKhkXfrPTZQKtAonQ=
 github.com/fsnotify/fsnotify v1.4.7 h1:IXs+QLmnXW2CcXuY+8Mzv/fWEsPGWxqefPtCP5CnV9I=
 github.com/fsnotify/fsnotify v1.4.7/go.mod h1:jwhsz4b93w/PPRr/qN1Yymfu8t87LnFCMoQvtojpjFo=
+github.com/golang/protobuf v1.2.0/go.mod h1:6lQm79b+lXiMfvg/cZm0SGofjICqVBUtrP5yJMmIC1U=
 github.com/golang/protobuf v1.3.2 h1:6nsPYzhq5kReh6QImI3k5qWzO4PEbvbIW2cwSfR/6xs=
 github.com/golang/protobuf v1.3.2/go.mod h1:6lQm79b+lXiMfvg/cZm0SGofjICqVBUtrP5yJMmIC1U=
+github.com/golang/snappy v0.0.1 h1:Qgr9rKW7uDUkrbSmQeiDsGa8SjGyCOGtuasMWwvp2P4=
+github.com/golang/snappy v0.0.1/go.mod h1:/XxbfmMg8lxefKM7IXC3fBNl/7bRcc72aCRzEWrmP2Q=
 github.com/hpcloud/tail v1.0.0 h1:nfCOvKYfkgYP8hkirhJocXT2+zOD8yUNjXaWfTlyFKI=
 github.com/hpcloud/tail v1.0.0/go.mod h1:ab1qPbhIpdTxEkNHXyeSf5vhxWSCs/tWer42PpOxQnU=
 github.com/jessevdk/go-flags v1.4.0/go.mod h1:4FA24M0QyGHXBuZZK/XkWh8h0e1EYbRYJSGM75WSRxI=
 github.com/onsi/ginkgo v1.6.0 h1:Ix8l273rp3QzYgXSR+c8d1fTG7UPgYkOSELPhiY/YGw=
 github.com/onsi/ginkgo v1.6.0/go.mod h1:lLunBs/Ym6LB5Z9jYTR76FiuTmxDTDusOGeTQH+WWjE=
-github.com/onsi/gomega v1.4.1 h1:PZSj/UFNaVp3KxrzHOcS7oyuWA7LoOY/77yCTEFu21U=
-github.com/onsi/gomega v1.4.1/go.mod h1:C1qb7wdrVGGVU+Z6iS04AVkA3Q65CEZX59MT0QO5uiA=
-golang.org/x/net v0.0.0-20180719180050-a680a1efc54d h1:i6RB+Qz1ug7TvJdY4zieRMpnLAtkHSHTOvApNXfLT4A=
-golang.org/x/net v0.0.0-20180719180050-a680a1efc54d/go.mod h1:mL1N/T3taQHkDXs73rZJwtUhF3w3ftmwwsq0BUmARs4=
+github.com/onsi/ginkgo v1.7.0/go.mod h1:lLunBs/Ym6LB5Z9jYTR76FiuTmxDTDusOGeTQH+WWjE=
+github.com/onsi/ginkgo v1.11.0 h1:JAKSXpt1YjtLA7YpPiqO9ss6sNXEsPfSGdwN0UHqzrw=
+github.com/onsi/ginkgo v1.11.0/go.mod h1:lLunBs/Ym6LB5Z9jYTR76FiuTmxDTDusOGeTQH+WWjE=
+github.com/onsi/gomega v1.4.3/go.mod h1:ex+gbHU/CVuBBDIJjb2X0qEXbFg53c61hWP/1CpauHY=
+github.com/onsi/gomega v1.8.1 h1:C5Dqfs/LeauYDX0jJXIe2SWmwCbGzx9yF8C8xy3Lh34=
+github.com/onsi/gomega v1.8.1/go.mod h1:Ho0h+IUsWyvy1OpqCwxlQ/21gkhVunqlU8fDGcoTdcA=
+github.com/syndtr/goleveldb v1.0.1-0.20190923125748-758128399b1d h1:gZZadD8H+fF+n9CmNhYL1Y0dJB+kLOmKd7FbPJLeGHs=
+github.com/syndtr/goleveldb v1.0.1-0.20190923125748-758128399b1d/go.mod h1:9OrXJhf154huy1nPWmuSrkgjPUtUNhA+Zmy+6AESzuA=
+golang.org/x/net v0.0.0-20180906233101-161cd47e91fd h1:nTDtHvHSdCn1m6ITfMRqtOd/9+7a3s8RBNOZ3eYZzJA=
+golang.org/x/net v0.0.0-20180906233101-161cd47e91fd/go.mod h1:mL1N/T3taQHkDXs73rZJwtUhF3w3ftmwwsq0BUmARs4=
+golang.org/x/sync v0.0.0-20180314180146-1d60e4601c6f/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
+golang.org/x/sys v0.0.0-20180909124046-d0be0721c37e/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
 golang.org/x/sys v0.0.0-20191010194322-b09406accb47 h1:/XfQ9z7ib8eEJX2hdgFTZJ/ntt0swNk5oYBziWeTCvY=
 golang.org/x/sys v0.0.0-20191010194322-b09406accb47/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/text v0.3.0 h1:g61tztE5qeGQ89tm6NTjjM9VPIm088od1l6aSorWRWg=
 golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
+golang.org/x/xerrors v0.0.0-20190717185122-a985d3407aa7 h1:9zdDQZ7Thm29KFXgAX/+yaf3eVbP7djjWp/dXAppNCc=
+golang.org/x/xerrors v0.0.0-20190717185122-a985d3407aa7/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/fsnotify.v1 v1.4.7 h1:xOHLXZwVvI9hhs+cLKq5+I5onOuwQLhQwiu63xxlHs4=
@@ -65,3 +72,5 @@ gopkg.in/tomb.v1 v1.0.0-20141024135613-dd632973f1e7 h1:uRGJdciOHaEIrze2W8Q3AKkep
 gopkg.in/tomb.v1 v1.0.0-20141024135613-dd632973f1e7/go.mod h1:dt/ZhP58zS4L8KSrWDmTeBkI65Dw0HsyUHuEVlX15mw=
 gopkg.in/yaml.v2 v2.2.1 h1:mUhvW9EsL+naU5Q3cakzfE91YhliOondGd6ZrsDBHQE=
 gopkg.in/yaml.v2 v2.2.1/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
+gopkg.in/yaml.v2 v2.2.4 h1:/eiJrUcujPVeJ3xlSWaiNi3uSVmDGBK1pDHUHAnao1I=
+gopkg.in/yaml.v2 v2.2.4/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=

blockchain/indexers/addrindex.go

@@ -325,12 +325,9 @@ func dbFetchAddrIndexEntries(bucket internalBucket, addrKey [addrKeySize]byte, n
 			// Ensure any deserialization errors are returned as
 			// database corruption errors.
 			if isDeserializeErr(err) {
-				err = database.Error{
-					ErrorCode: database.ErrCorruption,
-					Description: fmt.Sprintf("failed to "+
-						"deserialized address index "+
-						"for key %x: %v", addrKey, err),
-				}
+				str := fmt.Sprintf("failed to deserialized address index "+
+					"for key %x: %v", addrKey, err)
+				err = database.MakeError(database.ErrCorruption, str)
 			}
 
 			return nil, 0, err

blockchain/indexers/manager.go

@@ -7,6 +7,7 @@ package indexers
 
 import (
 	"context"
+	"errors"
 	"fmt"
 
 	"github.com/decred/dcrd/blockchain/v3/internal/progresslog"
@@ -60,11 +61,9 @@ func dbFetchIndexerTip(dbTx database.Tx, idxKey []byte) (*chainhash.Hash, int32,
 	indexesBucket := dbTx.Metadata().Bucket(indexTipsBucketName)
 	serialized := indexesBucket.Get(idxKey)
 	if len(serialized) < chainhash.HashSize+4 {
-		return nil, 0, database.Error{
-			ErrorCode: database.ErrCorruption,
-			Description: fmt.Sprintf("unexpected end of data for "+
-				"index %q tip", string(idxKey)),
-		}
+		str := fmt.Sprintf("unexpected end of data for index %q tip",
+			string(idxKey))
+		return nil, 0, database.MakeError(database.ErrCorruption, str)
 	}
 
 	var hash chainhash.Hash
@@ -103,11 +102,9 @@ func dbFetchIndexerVersion(dbTx database.Tx, idxKey []byte) (uint32, error) {
 	}
 
 	if len(serialized) < 4 {
-		return 0, database.Error{
-			ErrorCode: database.ErrCorruption,
-			Description: fmt.Sprintf("unexpected end of data for "+
-				"index %q version", string(idxKey)),
-		}
+		str := fmt.Sprintf("unexpected end of data for index %q version",
+			string(idxKey))
+		return 0, database.MakeError(database.ErrCorruption, str)
 	}
 
 	version := byteOrder.Uint32(serialized)
@@ -760,7 +757,7 @@ func dropIndexMetadata(db database.DB, idxKey []byte, idxName string) error {
 		}
 
 		err = meta.DeleteBucket(idxKey)
-		if err != nil && !database.IsError(err, database.ErrBucketNotFound) {
+		if err != nil && !errors.Is(err, database.ErrBucketNotFound) {
 			return err
 		}
 

blockchain/indexers/txindex.go

@@ -217,21 +217,16 @@ func dbFetchTxIndexEntry(dbTx database.Tx, txHash *chainhash.Hash) (*TxIndexEntr
 
 	// Ensure the serialized data has enough bytes to properly deserialize.
 	if len(serializedData) < txEntrySize {
-		return nil, database.Error{
-			ErrorCode: database.ErrCorruption,
-			Description: fmt.Sprintf("corrupt transaction index "+
-				"entry for %s", txHash),
-		}
+		str := fmt.Sprintf("corrupt transaction index entry for %s", txHash)
+		return nil, database.MakeError(database.ErrCorruption, str)
 	}
 
 	// Load the block hash associated with the block ID.
 	hash, err := dbFetchBlockHashBySerializedID(dbTx, serializedData[0:4])
 	if err != nil {
-		return nil, database.Error{
-			ErrorCode: database.ErrCorruption,
-			Description: fmt.Sprintf("corrupt transaction index "+
-				"entry for %s: %v", txHash, err),
-		}
+		str := fmt.Sprintf("corrupt transaction index entry for %s: %v",
+			txHash, err)
+		return nil, database.MakeError(database.ErrCorruption, str)
 	}
 
 	// Deserialize the final entry.

blockmanager.go

@@ -1069,8 +1069,7 @@ func (b *blockManager) handleBlockMsg(bmsg *blockMsg) {
 				blockHash, err)
 		}
 		var dbErr database.Error
-		if errors.As(err, &dbErr) && dbErr.ErrorCode ==
-			database.ErrCorruption {
+		if errors.As(err, &dbErr) && errors.Is(dbErr, database.ErrCorruption) {
 			bmgrLog.Errorf("Critical failure: %v", dbErr.Error())
 		}
 
@@ -2586,9 +2585,7 @@ func loadBlockDB(params *chaincfg.Params) (database.DB, error) {
 		// Return the error if it's not because the database doesn't
 		// exist.
 		var dbErr database.Error
-		if !errors.As(err, &dbErr) || dbErr.ErrorCode !=
-			database.ErrDbDoesNotExist {
-
+		if !errors.As(err, &dbErr) || !errors.Is(dbErr, database.ErrDbDoesNotExist) {
 			return nil, err
 		}
 

cmd/addblock/addblock.go

@@ -6,6 +6,7 @@
 package main
 
 import (
+	"errors"
 	"os"
 	"path/filepath"
 	"runtime"
@@ -38,9 +39,8 @@ func loadBlockDB() (database.DB, error) {
 	if err != nil {
 		// Return the error if it's not because the database doesn't
 		// exist.
-		if dbErr, ok := err.(database.Error); !ok || dbErr.ErrorCode !=
-			database.ErrDbDoesNotExist {
-
+		var dbErr database.Error
+		if !errors.As(err, &dbErr) || !errors.Is(dbErr, database.ErrDbDoesNotExist) {
 			return nil, err
 		}
 

database/cmd/dbtool/insecureimport.go

@@ -7,6 +7,7 @@ package main
 
 import (
 	"encoding/binary"
+	"errors"
 	"fmt"
 	"io"
 	"os"
@@ -376,8 +377,8 @@ func (cmd *importCmd) Execute(args []string) error {
 		resultsChan := importer.Import()
 		results := <-resultsChan
 		if results.err != nil {
-			dbErr, ok := results.err.(database.Error)
-			if !ok || ok && dbErr.ErrorCode != database.ErrDbNotOpen {
+			var dbErr database.Error
+			if !errors.As(results.err, &dbErr) || !errors.Is(dbErr, database.ErrDbNotOpen) {
 				shutdownChannel <- results.err
 				return
 			}

database/cmd/dbtool/main.go

@@ -6,6 +6,7 @@
 package main
 
 import (
+	"errors"
 	"os"
 	"path/filepath"
 	"runtime"
@@ -37,9 +38,8 @@ func loadBlockDB() (database.DB, error) {
 	if err != nil {
 		// Return the error if it's not because the database doesn't
 		// exist.
-		if dbErr, ok := err.(database.Error); !ok || dbErr.ErrorCode !=
-			database.ErrDbDoesNotExist {
-
+		var dbErr database.Error
+		if !errors.As(err, &dbErr) || !errors.Is(dbErr, database.ErrDbDoesNotExist) {
 			return nil, err
 		}