blockchain: fix errorlint warnings

blockchain/chain.go

@@ -1151,8 +1151,6 @@ func (b *BlockChain) reorganizeChainInternal(targetTip *blockNode) error {
 		if err != nil {
 			return err
 		}
-
-		tip = n
 	}
 
 	return nil

blockchain/common_test.go

@@ -65,7 +65,7 @@ func chainSetup(dbName string, params *chaincfg.Params) (*BlockChain, func(), er
 	if testDbType == "memdb" {
 		ndb, err := database.Create(testDbType)
 		if err != nil {
-			return nil, nil, fmt.Errorf("error creating db: %v", err)
+			return nil, nil, fmt.Errorf("error creating db: %w", err)
 		}
 		db = ndb
 
@@ -78,7 +78,7 @@ func chainSetup(dbName string, params *chaincfg.Params) (*BlockChain, func(), er
 		// Create the directory for test database.
 		dbPath, err := ioutil.TempDir("", dbName)
 		if err != nil {
-			err := fmt.Errorf("unable to create test db path: %v",
+			err := fmt.Errorf("unable to create test db path: %w",
 				err)
 			return nil, nil, err
 		}
@@ -87,7 +87,7 @@ func chainSetup(dbName string, params *chaincfg.Params) (*BlockChain, func(), er
 		ndb, err := database.Create(testDbType, dbPath, blockDataNet)
 		if err != nil {
 			os.RemoveAll(dbPath)
-			return nil, nil, fmt.Errorf("error creating db: %v", err)
+			return nil, nil, fmt.Errorf("error creating db: %w", err)
 		}
 		db = ndb
 
@@ -120,7 +120,7 @@ func chainSetup(dbName string, params *chaincfg.Params) (*BlockChain, func(), er
 
 	if err != nil {
 		teardown()
-		err := fmt.Errorf("failed to create chain instance: %v", err)
+		err := fmt.Errorf("failed to create chain instance: %w", err)
 		return nil, nil, err
 	}
 

blockchain/fullblocks_test.go

@@ -60,7 +60,7 @@ func chainSetup(dbName string, params *chaincfg.Params) (*blockchain.BlockChain,
 	if testDbType == "memdb" {
 		ndb, err := database.Create(testDbType)
 		if err != nil {
-			return nil, nil, fmt.Errorf("error creating db: %v", err)
+			return nil, nil, fmt.Errorf("error creating db: %w", err)
 		}
 		db = ndb
 
@@ -73,7 +73,7 @@ func chainSetup(dbName string, params *chaincfg.Params) (*blockchain.BlockChain,
 		// Create the directory for test database.
 		dbPath, err := ioutil.TempDir("", dbName)
 		if err != nil {
-			err := fmt.Errorf("unable to create test db path: %v",
+			err := fmt.Errorf("unable to create test db path: %w",
 				err)
 			return nil, nil, err
 		}
@@ -82,7 +82,7 @@ func chainSetup(dbName string, params *chaincfg.Params) (*blockchain.BlockChain,
 		ndb, err := database.Create(testDbType, dbPath, blockDataNet)
 		if err != nil {
 			os.RemoveAll(dbPath)
-			return nil, nil, fmt.Errorf("error creating db: %v", err)
+			return nil, nil, fmt.Errorf("error creating db: %w", err)
 		}
 		db = ndb
 
@@ -115,7 +115,7 @@ func chainSetup(dbName string, params *chaincfg.Params) (*blockchain.BlockChain,
 
 	if err != nil {
 		teardown()
-		err := fmt.Errorf("failed to create chain instance: %v", err)
+		err := fmt.Errorf("failed to create chain instance: %w", err)
 		return nil, nil, err
 	}
 

blockchain/indexers/common.go

@@ -1,5 +1,5 @@
 // Copyright (c) 2016 The btcsuite developers
-// Copyright (c) 2016-2019 The Decred developers
+// Copyright (c) 2016-2020 The Decred developers
 // Use of this source code is governed by an ISC
 // license that can be found in the LICENSE file.
 
@@ -149,8 +149,8 @@ func (e errDeserialize) Error() string {
 // isDeserializeErr returns whether or not the passed error is an errDeserialize
 // error.
 func isDeserializeErr(err error) bool {
-	_, ok := err.(errDeserialize)
-	return ok
+	var derr errDeserialize
+	return errors.As(err, &derr)
 }
 
 // internalBucket is an abstraction over a database bucket.  It is used to make

blockchain/stake/internal/ticketdb/chainio_test.go

@@ -7,6 +7,7 @@ package ticketdb
 import (
 	"bytes"
 	"encoding/hex"
+	"errors"
 	"io/ioutil"
 	"os"
 	"reflect"
@@ -115,11 +116,11 @@ func TestDbInfoDeserializeErrors(t *testing.T) {
 		},
 	}
 
+	var ticketDBErr DBError
 	for _, test := range tests {
 		// Ensure the expected error type is returned.
 		_, err := deserializeDatabaseInfo(test.serialized)
-		ticketDBErr, ok := err.(DBError)
-		if !ok {
+		if !errors.As(err, &ticketDBErr) {
 			t.Errorf("couldn't convert deserializeDatabaseInfo error "+
 				"to ticket db error (err: %v)", err)
 			continue
@@ -208,11 +209,11 @@ func TestBestChainStateDeserializeErrors(t *testing.T) {
 		},
 	}
 
+	var ticketDBErr DBError
 	for _, test := range tests {
 		// Ensure the expected error type is returned.
 		_, err := deserializeBestChainState(test.serialized)
-		ticketDBErr, ok := err.(DBError)
-		if !ok {
+		if !errors.As(err, &ticketDBErr) {
 			t.Errorf("couldn't convert deserializeBestChainState error "+
 				"to ticket db error (err: %v)", err)
 			continue
@@ -306,11 +307,11 @@ func TestBlockUndoDataDeserializingErrors(t *testing.T) {
 		},
 	}
 
+	var ticketDBErr DBError
 	for _, test := range tests {
 		// Ensure the expected error type is returned.
 		_, err := deserializeBlockUndoData(test.serialized)
-		ticketDBErr, ok := err.(DBError)
-		if !ok {
+		if !errors.As(err, &ticketDBErr) {
 			t.Errorf("couldn't convert deserializeBlockUndoData error "+
 				"to ticket db error (err: %v)", err)
 			continue
@@ -395,11 +396,11 @@ func TestTicketHashesDeserializingErrors(t *testing.T) {
 		},
 	}
 
+	var ticketDBErr DBError
 	for _, test := range tests {
 		// Ensure the expected error type is returned.
 		_, err := deserializeTicketHashes(test.serialized)
-		ticketDBErr, ok := err.(DBError)
-		if !ok {
+		if !errors.As(err, &ticketDBErr) {
 			t.Errorf("couldn't convert deserializeTicketHashes error "+
 				"to ticket db error (err: %v)", err)
 			continue

blockchain/stake/staketx_test.go

@@ -665,7 +665,7 @@ func TestSSGenErrors(t *testing.T) {
 	ssgenNoDiscriminator.SetIndex(0)
 
 	err = stake.CheckSSGen(ssgenNoDiscriminator.MsgTx(), withTreasury)
-	if err.(stake.RuleError).GetCode() !=
+	if !errors.As(err, &serr) || serr.GetCode() !=
 		stake.ErrSSGenInvalidDiscriminatorLength {
 		t.Errorf("CheckSSGen should have returned %v but instead returned %v",
 			stake.ErrSSGenInvalidDiscriminatorLength, err)
@@ -680,7 +680,7 @@ func TestSSGenErrors(t *testing.T) {
 	ssgenInvalidDiscriminator.SetIndex(0)
 
 	err = stake.CheckSSGen(ssgenInvalidDiscriminator.MsgTx(), withTreasury)
-	if err.(stake.RuleError).GetCode() !=
+	if !errors.As(err, &serr) || serr.GetCode() !=
 		stake.ErrSSGenInvalidDiscriminatorLength {
 		t.Errorf("CheckSSGen should have returned %v but instead returned %v",
 			stake.ErrSSGenInvalidDiscriminatorLength, err)
@@ -695,7 +695,7 @@ func TestSSGenErrors(t *testing.T) {
 	ssgenInvalidDiscriminator2.SetIndex(0)
 
 	err = stake.CheckSSGen(ssgenInvalidDiscriminator2.MsgTx(), withTreasury)
-	if err.(stake.RuleError).GetCode() !=
+	if !errors.As(err, &serr) || serr.GetCode() !=
 		stake.ErrSSGenUnknownDiscriminator {
 		t.Errorf("CheckSSGen should have returned %v but instead returned %v",
 			stake.ErrSSGenUnknownDiscriminator, err)
@@ -710,7 +710,7 @@ func TestSSGenErrors(t *testing.T) {
 	ssgenInvalidDiscriminator3.SetIndex(0)
 
 	err = stake.CheckSSGen(ssgenInvalidDiscriminator3.MsgTx(), withTreasury)
-	if err.(stake.RuleError).GetCode() !=
+	if !errors.As(err, &serr) || serr.GetCode() !=
 		stake.ErrSSGenBadGenOuts {
 		t.Errorf("CheckSSGen should have returned %v but instead returned %v",
 			stake.ErrSSGenBadGenOuts, err)
@@ -720,7 +720,8 @@ func TestSSGenErrors(t *testing.T) {
 	}
 	// Verify we don't crash in this case as well.
 	_, err = stake.GetSSGenTreasuryVotes(ssgenInvalidDiscriminator3.MsgTx().TxOut[4].PkScript)
-	if err.(stake.RuleError).GetCode() != stake.ErrSSGenInvalidNullScript {
+	if !errors.As(err, &serr) || serr.GetCode() !=
+		stake.ErrSSGenInvalidNullScript {
 		t.Error(err)
 	}
 
@@ -730,7 +731,7 @@ func TestSSGenErrors(t *testing.T) {
 	ssgenInvalidTVNoVote.SetIndex(0)
 
 	err = stake.CheckSSGen(ssgenInvalidTVNoVote.MsgTx(), withTreasury)
-	if err.(stake.RuleError).GetCode() !=
+	if !errors.As(err, &serr) || serr.GetCode() !=
 		stake.ErrSSGenInvalidTVLength {
 		t.Errorf("CheckSSGen should have returned %v but instead returned %v",
 			stake.ErrSSGenInvalidTVLength, err)
@@ -745,7 +746,7 @@ func TestSSGenErrors(t *testing.T) {
 	ssgenInvalidTVNoVote2.SetIndex(0)
 
 	err = stake.CheckSSGen(ssgenInvalidTVNoVote2.MsgTx(), withTreasury)
-	if err.(stake.RuleError).GetCode() !=
+	if !errors.As(err, &serr) || serr.GetCode() !=
 		stake.ErrSSGenInvalidTVLength {
 		t.Errorf("CheckSSGen should have returned %v but instead returned %v",
 			stake.ErrSSGenInvalidTVLength, err)
@@ -761,7 +762,7 @@ func TestSSGenErrors(t *testing.T) {
 	ssgenInvalidTVNoVote3.SetIndex(0)
 
 	err = stake.CheckSSGen(ssgenInvalidTVNoVote3.MsgTx(), withTreasury)
-	if err.(stake.RuleError).GetCode() !=
+	if !errors.As(err, &serr) || serr.GetCode() !=
 		stake.ErrSSGenInvalidTVLength {
 		t.Errorf("CheckSSGen should have returned %v but instead returned %v",
 			stake.ErrSSGenInvalidTVLength, err)
@@ -777,7 +778,7 @@ func TestSSGenErrors(t *testing.T) {
 	ssgenInvalidTVNoVote4.SetIndex(0)
 
 	err = stake.CheckSSGen(ssgenInvalidTVNoVote4.MsgTx(), withTreasury)
-	if err.(stake.RuleError).GetCode() !=
+	if !errors.As(err, &serr) || serr.GetCode() !=
 		stake.ErrSSGenInvalidTVLength {
 		t.Errorf("CheckSSGen should have returned %v but instead returned %v",
 			stake.ErrSSGenInvalidTVLength, err)
@@ -793,7 +794,7 @@ func TestSSGenErrors(t *testing.T) {
 	ssgenInvalidTVNoVote5.SetIndex(0)
 
 	err = stake.CheckSSGen(ssgenInvalidTVNoVote5.MsgTx(), withTreasury)
-	if err.(stake.RuleError).GetCode() !=
+	if !errors.As(err, &serr) || serr.GetCode() !=
 		stake.ErrSSGenInvalidDiscriminatorLength {
 		t.Errorf("CheckSSGen should have returned %v but instead returned %v",
 			stake.ErrSSGenInvalidDiscriminatorLength, err)
@@ -808,7 +809,7 @@ func TestSSGenErrors(t *testing.T) {
 	ssgenInvalidTVote.SetIndex(0)
 
 	err = stake.CheckSSGen(ssgenInvalidTVote.MsgTx(), withTreasury)
-	if err.(stake.RuleError).GetCode() !=
+	if !errors.As(err, &serr) || serr.GetCode() !=
 		stake.ErrSSGenInvalidTreasuryVote {
 		t.Errorf("CheckSSGen should have returned %v but instead returned %v",
 			stake.ErrSSGenInvalidTreasuryVote, err)
@@ -823,7 +824,7 @@ func TestSSGenErrors(t *testing.T) {
 	ssgenInvalidTVote2.SetIndex(0)
 
 	err = stake.CheckSSGen(ssgenInvalidTVote2.MsgTx(), withTreasury)
-	if err.(stake.RuleError).GetCode() !=
+	if !errors.As(err, &serr) || serr.GetCode() !=
 		stake.ErrSSGenInvalidTreasuryVote {
 		t.Errorf("CheckSSGen should have returned %v but instead returned %v",
 			stake.ErrSSGenInvalidTreasuryVote, err)
@@ -838,7 +839,7 @@ func TestSSGenErrors(t *testing.T) {
 	ssgenInvalidTVote3.SetIndex(0)
 
 	err = stake.CheckSSGen(ssgenInvalidTVote3.MsgTx(), withTreasury)
-	if err.(stake.RuleError).GetCode() !=
+	if !errors.As(err, &serr) || serr.GetCode() !=
 		stake.ErrSSGenDuplicateTreasuryVote {
 		t.Errorf("CheckSSGen should have returned %v but instead returned %v",
 			stake.ErrSSGenDuplicateTreasuryVote, err)

blockchain/stake/tickets_test.go

@@ -719,31 +719,31 @@ func TestTicketDBGeneral(t *testing.T) {
 			// In memory addition test.
 			lotteryIV, err := calcHash256PRNGIVFromHeader(&header)
 			if err != nil {
-				return fmt.Errorf("failed to calc lottery IV: %v", err)
+				return fmt.Errorf("failed to calc lottery IV: %w", err)
 			}
 			bestNode, err = bestNode.ConnectNode(lotteryIV,
 				ticketsSpentInBlock(block), revokedTicketsInBlock(block),
 				ticketsToAdd)
 			if err != nil {
-				return fmt.Errorf("couldn't connect node: %v", err.Error())
+				return fmt.Errorf("couldn't connect node: %w", err)
 			}
 
 			// Write the new node to db.
 			nodesForward[i] = bestNode
 			blockHash := block.Hash()
 			err = WriteConnectedBestNode(dbTx, bestNode, *blockHash)
 			if err != nil {
-				return fmt.Errorf("failure writing the best node: %v",
-					err.Error())
+				return fmt.Errorf("failure writing the best node: %w",
+					err)
 			}
 
 			// Reload the node from DB and make sure it's the same.
 			blockHash = block.Hash()
 			loadedNode, err := LoadBestNode(dbTx, bestNode.Height(),
 				*blockHash, header, params)
 			if err != nil {
-				return fmt.Errorf("failed to load the best node: %v",
-					err.Error())
+				return fmt.Errorf("failed to load the best node: %w",
+					err)
 			}
 			err = nodesEqual(loadedNode, bestNode)
 			if err != nil {
@@ -795,7 +795,7 @@ func TestTicketDBGeneral(t *testing.T) {
 			// Negative test.
 			lotteryIV, err := calcHash256PRNGIVFromHeader(&header)
 			if err != nil {
-				return fmt.Errorf("failed to calc lottery IV: %v", err)
+				return fmt.Errorf("failed to calc lottery IV: %w", err)
 			}
 			bestNodeUsingDB, err = formerBestNode.DisconnectNode(lotteryIV, nil,
 				nil, nil)
@@ -826,8 +826,8 @@ func TestTicketDBGeneral(t *testing.T) {
 			err := WriteDisconnectedBestNode(dbTx, bestNode,
 				*parentBlockHash, formerBestNode.UndoData())
 			if err != nil {
-				return fmt.Errorf("failure writing the best node: %v",
-					err.Error())
+				return fmt.Errorf("failure writing the best node: %w",
+					err)
 			}
 
 			return nil
@@ -843,8 +843,8 @@ func TestTicketDBGeneral(t *testing.T) {
 			loadedNode, err := LoadBestNode(dbTx, bestNode.Height(),
 				*parentBlockHash, header, params)
 			if err != nil {
-				return fmt.Errorf("failed to load the best node: %v",
-					err.Error())
+				return fmt.Errorf("failed to load the best node: %w",
+					err)
 			}
 			err = nodesEqual(loadedNode, bestNode)
 			if err != nil {