*: fix staticcheck errors in folder bindinfo, config, infoschema, met…

…a and privilege (pingcap#13702)

bindinfo/bind_test.go

@@ -31,7 +31,6 @@ import (
 	"github.com/pingcap/tidb/store/mockstore"
 	"github.com/pingcap/tidb/store/mockstore/mocktikv"
 	"github.com/pingcap/tidb/util/logutil"
-	"github.com/pingcap/tidb/util/mock"
 	"github.com/pingcap/tidb/util/testkit"
 	"github.com/pingcap/tidb/util/testleak"
 	dto "github.com/prometheus/client_model/go"
@@ -53,7 +52,6 @@ type testSuite struct {
 	store     kv.Storage
 	domain    *domain.Domain
 	*parser.Parser
-	ctx *mock.Context
 }
 
 var mockTikv = flag.Bool("mockTikv", true, "use mock tikv store in bind test")

bindinfo/handle.go

@@ -492,11 +492,10 @@ func copyBindRecordUpdateMap(oldMap map[string]*bindRecordUpdate) map[string]*bi
 
 func (c cache) getBindRecord(hash, normdOrigSQL, db string) *BindRecord {
 	bindRecords := c[hash]
-	if bindRecords != nil {
-		for _, bindRecord := range bindRecords {
-			if bindRecord.OriginalSQL == normdOrigSQL && bindRecord.Db == db {
-				return bindRecord
-			}
+
+	for _, bindRecord := range bindRecords {
+		if bindRecord.OriginalSQL == normdOrigSQL && bindRecord.Db == db {
+			return bindRecord
 		}
 	}
 	return nil
@@ -534,7 +533,7 @@ func (h *BindHandle) logicalDeleteBindInfoSQL(originalSQL, db string, updateTs t
 		return sql
 	}
 	for i, sql := range bindingSQLs {
-		bindingSQLs[i] = fmt.Sprintf(`%s`, expression.Quote(sql))
+		bindingSQLs[i] = expression.Quote(sql)
 	}
 	return sql + fmt.Sprintf(` and bind_sql in (%s)`, strings.Join(bindingSQLs, ","))
 }

bindinfo/session_handle.go

@@ -88,11 +88,10 @@ func (h *SessionHandle) DropBindRecord(sctx sessionctx.Context, is infoschema.In
 func (h *SessionHandle) GetBindRecord(normdOrigSQL, db string) *BindRecord {
 	hash := parser.DigestHash(normdOrigSQL)
 	bindRecords := h.ch[hash]
-	if bindRecords != nil {
-		for _, bindRecord := range bindRecords {
-			if bindRecord.OriginalSQL == normdOrigSQL && bindRecord.Db == db {
-				return bindRecord
-			}
+
+	for _, bindRecord := range bindRecords {
+		if bindRecord.OriginalSQL == normdOrigSQL && bindRecord.Db == db {
+			return bindRecord
 		}
 	}
 	return nil

config/config.go

@@ -153,9 +153,9 @@ func (b *nullableBool) UnmarshalJSON(data []byte) error {
 	if err = json.Unmarshal(data, &v); err != nil {
 		return err
 	}
-	switch v.(type) {
+	switch raw := v.(type) {
 	case bool:
-		*b = nullableBool{true, v.(bool)}
+		*b = nullableBool{true, raw}
 	default:
 		*b = nbUnset
 	}
@@ -635,10 +635,9 @@ func collectsDiff(i1, i2 interface{}, fieldPath string) map[string][]interface{}
 // Load loads config options from a toml file.
 func (c *Config) Load(confFile string) error {
 	metaData, err := toml.DecodeFile(confFile, c)
-	if c.TokenLimit <= 0 {
+	if c.TokenLimit == 0 {
 		c.TokenLimit = 1000
 	}
-
 	// If any items in confFile file are not mapped into the Config struct, issue
 	// an error and stop the server from starting.
 	undecoded := metaData.Undecoded()

infoschema/tables.go

@@ -2125,9 +2125,7 @@ func dataForClusterConfig(ctx sessionctx.Context) ([][]types.Datum, error) {
 	}
 	sort.Slice(results, func(i, j int) bool { return results[i].idx < results[j].idx })
 	for _, result := range results {
-		for _, row := range result.rows {
-			finalRows = append(finalRows, row)
-		}
+		finalRows = append(finalRows, result.rows...)
 	}
 	return finalRows, nil
 }
@@ -2211,7 +2209,6 @@ func createInfoSchemaTable(_ autoid.Allocator, meta *model.TableInfo) (table.Tab
 type infoschemaTable struct {
 	meta *model.TableInfo
 	cols []*table.Column
-	rows [][]types.Datum
 }
 
 // schemasSorter implements the sort.Interface interface, sorts DBInfo by name.

meta/meta.go

@@ -67,7 +67,6 @@ var (
 )
 
 var (
-
 	// ErrDBExists is the error for db exists.
 	ErrDBExists = terror.ClassMeta.New(codeDatabaseExists, "database already exists")
 	// ErrDBNotExists is the error for db not exists.
@@ -820,13 +819,10 @@ func (m *Meta) SetSchemaDiff(diff *model.SchemaDiff) error {
 
 // meta error codes.
 const (
-	codeInvalidTableKey terror.ErrCode = 1
-	codeInvalidDBKey                   = 2
-
-	codeDatabaseExists    = 1007
-	codeDatabaseNotExists = 1049
-	codeTableExists       = 1050
-	codeTableNotExists    = 1146
+	codeDatabaseExists    terror.ErrCode = 1007
+	codeDatabaseNotExists terror.ErrCode = 1049
+	codeTableExists       terror.ErrCode = 1050
+	codeTableNotExists    terror.ErrCode = 1146
 )
 
 func init() {

privilege/privileges/cache.go

@@ -147,9 +147,7 @@ type MySQLPrivilege struct {
 // FindAllRole is used to find all roles grant to this user.
 func (p *MySQLPrivilege) FindAllRole(activeRoles []*auth.RoleIdentity) []*auth.RoleIdentity {
 	queue, head := make([]*auth.RoleIdentity, 0, len(activeRoles)), 0
-	for _, r := range activeRoles {
-		queue = append(queue, r)
-	}
+	queue = append(queue, activeRoles...)
 	// Using breadth first search to find all roles grant to this user.
 	visited, ret := make(map[string]bool), make([]*auth.RoleIdentity, 0)
 	for head < len(queue) {

privilege/privileges/cache_test.go

@@ -28,7 +28,6 @@ var _ = Suite(&testCacheSuite{})
 
 type testCacheSuite struct {
 	store  kv.Storage
-	dbName string
 	domain *domain.Domain
 }