linter: fix linter error when make dev locally

ddl/column_type_change_test.go

@@ -1764,7 +1764,7 @@ func (s *testColumnTypeChangeSuite) TestChangingColOriginDefaultValueAfterAddCol
 	tk1 := testkit.NewTestKit(c, s.store)
 	tk1.MustExec("use test")
 
-	tk.MustExec(fmt.Sprintf("set time_zone = 'UTC'"))
+	tk.MustExec("set time_zone = 'UTC'")
 	tk.MustExec("drop table if exists t")
 	tk.MustExec("create table t(a VARCHAR(31) NULL DEFAULT 'wwrzfwzb01j6ddj', b DECIMAL(12,0) NULL DEFAULT '-729850476163')")
 	tk.MustExec("ALTER TABLE t ADD COLUMN x CHAR(218) NULL DEFAULT 'lkittuae'")

executor/builder.go

@@ -2791,7 +2791,7 @@ func (b *executorBuilder) buildTableReader(v *plannercore.PhysicalTableReader) E
 	if !b.ctx.GetSessionVars().UseDynamicPartitionPrune() {
 		return ret
 	}
-	// When isPartition is set, it means the union rewriting is done, so a partition reader is prefered.
+	// When isPartition is set, it means the union rewriting is done, so a partition reader is preferred.
 	if ok, _ := ts.IsPartition(); ok {
 		return ret
 	}
@@ -3020,7 +3020,7 @@ func (b *executorBuilder) buildIndexReader(v *plannercore.PhysicalIndexReader) E
 	if !b.ctx.GetSessionVars().UseDynamicPartitionPrune() {
 		return ret
 	}
-	// When isPartition is set, it means the union rewriting is done, so a partition reader is prefered.
+	// When isPartition is set, it means the union rewriting is done, so a partition reader is preferred.
 	if ok, _ := is.IsPartition(); ok {
 		return ret
 	}

go.mod

@@ -74,6 +74,7 @@ require (
 	golang.org/x/tools v0.1.0
 	google.golang.org/grpc v1.27.1
 	gopkg.in/check.v1 v1.0.0-20201130134442-10cb98267c6c // indirect
+	honnef.co/go/tools v0.2.0 // indirect
 	modernc.org/mathutil v1.2.2 // indirect
 	sourcegraph.com/sourcegraph/appdash v0.0.0-20190731080439-ebfcffb1b5c0
 	sourcegraph.com/sourcegraph/appdash-data v0.0.0-20151005221446-73f23eafcf67

planner/core/logical_plan_builder.go

@@ -3634,7 +3634,6 @@ func (ds *DataSource) addExtraPIDColumn(info *extraPIDInfo) {
 
 	info.Columns = append(info.Columns, pidCol)
 	info.TblIDs = append(info.TblIDs, ds.TableInfo().ID)
-	return
 }
 
 var (

planner/core/preprocess.go

@@ -127,6 +127,9 @@ const (
 	inSequenceFunction
 )
 
+// Make linter happy.
+var _ = PreprocessorReturn{}.initedLastSnapshotTS
+
 // PreprocessorReturn is used to retain information obtained in the preprocessor.
 type PreprocessorReturn struct {
 	initedLastSnapshotTS bool

server/tidb_test.go

@@ -1495,7 +1495,7 @@ func (ts *tidbTestTopSQLSuite) TestTopSQLAgent(c *C) {
 	cancel() // cancel case 1
 
 	// case 2: agent hangs for a while
-	cancel = runWorkload(0, 10)
+	cancel2 := runWorkload(0, 10)
 	// empty agent address, should not collect records
 	dbt.mustExec("set @@global.tidb_top_sql_max_statement_count=5;")
 	dbt.mustExec("set @@tidb_top_sql_agent_address='';")
@@ -1508,13 +1508,15 @@ func (ts *tidbTestTopSQLSuite) TestTopSQLAgent(c *C) {
 	// agent server hangs for a while
 	agentServer.HangFromNow(time.Second * 6)
 	// run another set of SQL queries
-	cancel()
-	cancel = runWorkload(11, 20)
+	cancel2()
+
+	cancel3 := runWorkload(11, 20)
 	agentServer.WaitCollectCnt(1, time.Second*8)
 	checkFn(5)
+	cancel3()
 
 	// case 3: agent restart
-	cancel = runWorkload(0, 10)
+	cancel4 := runWorkload(0, 10)
 	// empty agent address, should not collect records
 	dbt.mustExec("set @@tidb_top_sql_agent_address='';")
 	agentServer.WaitCollectCnt(1, time.Second*4)
@@ -1524,9 +1526,9 @@ func (ts *tidbTestTopSQLSuite) TestTopSQLAgent(c *C) {
 	agentServer.WaitCollectCnt(1, time.Second*8)
 	checkFn(5)
 	// run another set of SQL queries
-	cancel()
+	cancel4()
 
-	cancel = runWorkload(11, 20)
+	cancel5 := runWorkload(11, 20)
 	// agent server shutdown
 	agentServer.Stop()
 	// agent server restart
@@ -1536,6 +1538,7 @@ func (ts *tidbTestTopSQLSuite) TestTopSQLAgent(c *C) {
 	// check result
 	agentServer.WaitCollectCnt(2, time.Second*8)
 	checkFn(5)
+	cancel5()
 }
 
 func (ts *tidbTestTopSQLSuite) loopExec(ctx context.Context, c *C, fn func(db *sql.DB)) {

structure/type.go

@@ -39,6 +39,9 @@ const (
 	ListData TypeFlag = 'l'
 )
 
+// Make linter happy, since encodeHashMetaKey is unused in this repo.
+var _ = (&TxStructure{}).encodeHashMetaKey
+
 func (t *TxStructure) encodeStringDataKey(key []byte) kv.Key {
 	// for codec Encode, we may add extra bytes data, so here and following encode
 	// we will use extra length like 4 for a little optimization.