Enable more `golangci-lint` linters (#1181)

.golangci.yml

@@ -4,14 +4,19 @@ linters:
   disable:
     - errcheck
   enable:
+    - bodyclose
+    - containedctx
     - contextcheck
+    - dogsled
     - durationcheck
     - errname
+    - errorlint
     - execinquery
     - gofmt
     - ifshort
     - misspell
     - nilerr
+    - nilnil
     - noctx
     - nolintlint
     - nosprintfhostport
@@ -19,6 +24,7 @@ linters:
     - rowserrcheck
     - sqlclosecheck
     - unconvert
+    - unparam
     - unused
     - wastedassign
     - whitespace

go/base/context.go

@@ -858,7 +858,7 @@ func (this *MigrationContext) ReadConfigFile() error {
 	if cfg.Section("osc").HasKey("chunk_size") {
 		this.config.Osc.Chunk_Size, err = cfg.Section("osc").Key("chunk_size").Int64()
 		if err != nil {
-			return fmt.Errorf("Unable to read osc chunk size: %s", err.Error())
+			return fmt.Errorf("Unable to read osc chunk size: %w", err)
 		}
 	}
 
@@ -873,7 +873,7 @@ func (this *MigrationContext) ReadConfigFile() error {
 	if cfg.Section("osc").HasKey("max_lag_millis") {
 		this.config.Osc.Max_Lag_Millis, err = cfg.Section("osc").Key("max_lag_millis").Int64()
 		if err != nil {
-			return fmt.Errorf("Unable to read max lag millis: %s", err.Error())
+			return fmt.Errorf("Unable to read max lag millis: %w", err)
 		}
 	}
 

go/logic/applier.go

@@ -1134,7 +1134,7 @@ func (this *Applier) ApplyDMLEventQueries(dmlEvents [](*binlog.BinlogDMLEvent))
 				}
 				result, err := tx.Exec(buildResult.query, buildResult.args...)
 				if err != nil {
-					err = fmt.Errorf("%s; query=%s; args=%+v", err.Error(), buildResult.query, buildResult.args)
+					err = fmt.Errorf("%w; query=%s; args=%+v", err, buildResult.query, buildResult.args)
 					return rollback(err)
 				}
 

go/logic/inspect.go

@@ -8,6 +8,7 @@ package logic
 import (
 	"context"
 	gosql "database/sql"
+	"errors"
 	"fmt"
 	"reflect"
 	"strings"
@@ -554,13 +555,11 @@ func (this *Inspector) CountTableRows(ctx context.Context) error {
 	query := fmt.Sprintf(`select /* gh-ost */ count(*) as count_rows from %s.%s`, sql.EscapeName(this.migrationContext.DatabaseName), sql.EscapeName(this.migrationContext.OriginalTableName))
 	var rowsEstimate int64
 	if err := conn.QueryRowContext(ctx, query).Scan(&rowsEstimate); err != nil {
-		switch err {
-		case context.Canceled, context.DeadlineExceeded:
+		if errors.Is(err, context.Canceled) || errors.Is(err, context.DeadlineExceeded) {
 			this.migrationContext.Log.Infof("exact row count cancelled (%s), likely because I'm about to cut over. I'm going to kill that query.", ctx.Err())
 			return mysql.Kill(this.db, connectionID)
-		default:
-			return err
 		}
+		return err
 	}
 
 	// row count query finished. nil out the cancel func, so the main migration thread

go/logic/migrator.go

@@ -391,9 +391,9 @@ func (this *Migrator) Migrate() (err error) {
 	if err := this.applier.ReadMigrationRangeValues(); err != nil {
 		return err
 	}
-	if err := this.initiateThrottler(); err != nil {
-		return err
-	}
+
+	this.initiateThrottler()
+
 	if err := this.hooksExecutor.onBeforeRowCopy(); err != nil {
 		return err
 	}
@@ -1096,7 +1096,7 @@ func (this *Migrator) addDMLEventsListener() error {
 }
 
 // initiateThrottler kicks in the throttling collection and the throttling checks.
-func (this *Migrator) initiateThrottler() error {
+func (this *Migrator) initiateThrottler() {
 	this.throttler = NewThrottler(this.migrationContext, this.applier, this.inspector, this.appVersion)
 
 	go this.throttler.initiateThrottlerCollection(this.firstThrottlingCollected)
@@ -1106,8 +1106,6 @@ func (this *Migrator) initiateThrottler() error {
 	<-this.firstThrottlingCollected // other, general metrics
 	this.migrationContext.Log.Infof("First throttle metrics collected")
 	go this.throttler.initiateThrottlerChecks()
-
-	return nil
 }
 
 func (this *Migrator) initiateApplier() error {

go/logic/throttler.go

@@ -308,6 +308,8 @@ func (this *Throttler) collectThrottleHTTPStatus(firstThrottlingCollected chan<-
 		if err != nil {
 			return false, err
 		}
+		defer resp.Body.Close()
+
 		atomic.StoreInt64(&this.migrationContext.ThrottleHTTPStatusCode, int64(resp.StatusCode))
 		return false, nil
 	}

go/sql/parser.go

@@ -62,7 +62,7 @@ func NewParserFromAlterStatement(alterStatement string) *AlterTableParser {
 	return parser
 }
 
-func (this *AlterTableParser) tokenizeAlterStatement(alterStatement string) (tokens []string, err error) {
+func (this *AlterTableParser) tokenizeAlterStatement(alterStatement string) (tokens []string) {
 	terminatingQuote := rune(0)
 	f := func(c rune) bool {
 		switch {
@@ -86,7 +86,7 @@ func (this *AlterTableParser) tokenizeAlterStatement(alterStatement string) (tok
 	for i := range tokens {
 		tokens[i] = strings.TrimSpace(tokens[i])
 	}
-	return tokens, nil
+	return tokens
 }
 
 func (this *AlterTableParser) sanitizeQuotesFromAlterStatement(alterStatement string) (strippedStatement string) {
@@ -95,7 +95,7 @@ func (this *AlterTableParser) sanitizeQuotesFromAlterStatement(alterStatement st
 	return strippedStatement
 }
 
-func (this *AlterTableParser) parseAlterToken(alterToken string) (err error) {
+func (this *AlterTableParser) parseAlterToken(alterToken string) {
 	{
 		// rename
 		allStringSubmatch := renameColumnRegexp.FindAllStringSubmatch(alterToken, -1)
@@ -131,7 +131,6 @@ func (this *AlterTableParser) parseAlterToken(alterToken string) (err error) {
 			this.isAutoIncrementDefined = true
 		}
 	}
-	return nil
 }
 
 func (this *AlterTableParser) ParseAlterStatement(alterStatement string) (err error) {
@@ -151,8 +150,7 @@ func (this *AlterTableParser) ParseAlterStatement(alterStatement string) (err er
 			break
 		}
 	}
-	alterTokens, _ := this.tokenizeAlterStatement(this.alterStatementOptions)
-	for _, alterToken := range alterTokens {
+	for _, alterToken := range this.tokenizeAlterStatement(this.alterStatementOptions) {
 		alterToken = this.sanitizeQuotesFromAlterStatement(alterToken)
 		this.parseAlterToken(alterToken)
 		this.alterTokens = append(this.alterTokens, alterToken)

go/sql/parser_test.go

@@ -99,37 +99,37 @@ func TestTokenizeAlterStatement(t *testing.T) {
 	parser := NewAlterTableParser()
 	{
 		alterStatement := "add column t int"
-		tokens, _ := parser.tokenizeAlterStatement(alterStatement)
+		tokens := parser.tokenizeAlterStatement(alterStatement)
 		test.S(t).ExpectTrue(reflect.DeepEqual(tokens, []string{"add column t int"}))
 	}
 	{
 		alterStatement := "add column t int, change column i int"
-		tokens, _ := parser.tokenizeAlterStatement(alterStatement)
+		tokens := parser.tokenizeAlterStatement(alterStatement)
 		test.S(t).ExpectTrue(reflect.DeepEqual(tokens, []string{"add column t int", "change column i int"}))
 	}
 	{
 		alterStatement := "add column t int, change column i int 'some comment'"
-		tokens, _ := parser.tokenizeAlterStatement(alterStatement)
+		tokens := parser.tokenizeAlterStatement(alterStatement)
 		test.S(t).ExpectTrue(reflect.DeepEqual(tokens, []string{"add column t int", "change column i int 'some comment'"}))
 	}
 	{
 		alterStatement := "add column t int, change column i int 'some comment, with comma'"
-		tokens, _ := parser.tokenizeAlterStatement(alterStatement)
+		tokens := parser.tokenizeAlterStatement(alterStatement)
 		test.S(t).ExpectTrue(reflect.DeepEqual(tokens, []string{"add column t int", "change column i int 'some comment, with comma'"}))
 	}
 	{
 		alterStatement := "add column t int, add column d decimal(10,2)"
-		tokens, _ := parser.tokenizeAlterStatement(alterStatement)
+		tokens := parser.tokenizeAlterStatement(alterStatement)
 		test.S(t).ExpectTrue(reflect.DeepEqual(tokens, []string{"add column t int", "add column d decimal(10,2)"}))
 	}
 	{
 		alterStatement := "add column t int, add column e enum('a','b','c')"
-		tokens, _ := parser.tokenizeAlterStatement(alterStatement)
+		tokens := parser.tokenizeAlterStatement(alterStatement)
 		test.S(t).ExpectTrue(reflect.DeepEqual(tokens, []string{"add column t int", "add column e enum('a','b','c')"}))
 	}
 	{
 		alterStatement := "add column t int(11), add column e enum('a','b','c')"
-		tokens, _ := parser.tokenizeAlterStatement(alterStatement)
+		tokens := parser.tokenizeAlterStatement(alterStatement)
 		test.S(t).ExpectTrue(reflect.DeepEqual(tokens, []string{"add column t int(11)", "add column e enum('a','b','c')"}))
 	}
 }