simple fixes for the staticcheck linter (#18923)

Note that this found 2 bugs where errors were being silently ignored.

These are really simple fixes that didn't require much thought.
There are still more staticcheck warnings that should be fixed.

Co-authored-by: ti-srebot <66930949+ti-srebot@users.noreply.github.com>

Makefile

@@ -305,7 +305,7 @@ tools/bin/failpoint-ctl: go.mod
 	$(GO) build -o $@ github.com/pingcap/failpoint/failpoint-ctl
 
 tools/bin/golangci-lint:
-	curl -sfL https://raw.githubusercontent.com/golangci/golangci-lint/master/install.sh| sh -s -- -b ./tools/bin v1.21.0
+	curl -sfL https://raw.githubusercontent.com/golangci/golangci-lint/master/install.sh| sh -s -- -b ./tools/bin v1.29.0
 
 # Usage:
 #

ddl/db_integration_test.go

@@ -2207,7 +2207,7 @@ func (s *testIntegrationSuite3) TestCreateTableWithAutoIdCache(c *C) {
 	tk.MustExec("drop table if exists t;")
 	tk.MustExec("drop table if exists t1;")
 	tk.MustExec("create table t(a int) auto_id_cache 100")
-	tblInfo, err = s.dom.InfoSchema().TableByName(model.NewCIStr("test"), model.NewCIStr("t"))
+	_, err = s.dom.InfoSchema().TableByName(model.NewCIStr("test"), model.NewCIStr("t"))
 	c.Assert(err, IsNil)
 
 	tk.MustExec("insert into t values()")
@@ -2223,7 +2223,7 @@ func (s *testIntegrationSuite3) TestCreateTableWithAutoIdCache(c *C) {
 	tk.MustExec("drop table if exists t;")
 	tk.MustExec("drop table if exists t1;")
 	tk.MustExec("create table t(a int null, b int auto_increment unique) auto_id_cache 100")
-	tblInfo, err = s.dom.InfoSchema().TableByName(model.NewCIStr("test"), model.NewCIStr("t"))
+	_, err = s.dom.InfoSchema().TableByName(model.NewCIStr("test"), model.NewCIStr("t"))
 	c.Assert(err, IsNil)
 
 	tk.MustExec("insert into t(b) values(NULL)")

ddl/ddl_api.go

@@ -3468,6 +3468,9 @@ func (d *ddl) getModifiableColumnJob(ctx sessionctx.Context, ident ast.Ident, or
 			ast.CharsetOpt{Chs: t.Meta().Charset, Col: t.Meta().Collate},
 			ast.CharsetOpt{Chs: schema.Charset, Col: schema.Collate},
 		)
+		if err != nil {
+			return nil, errors.Trace(err)
+		}
 	}
 
 	if err = setCharsetCollationFlenDecimal(&newCol.FieldType, chs, coll); err != nil {
@@ -4013,6 +4016,9 @@ func checkAlterTableCharset(tblInfo *model.TableInfo, dbInfo *model.DBInfo, toCh
 		ast.CharsetOpt{Chs: origCharset, Col: origCollate},
 		ast.CharsetOpt{Chs: dbInfo.Charset, Col: dbInfo.Collate},
 	)
+	if err != nil {
+		return doNothing, err
+	}
 
 	if err = checkModifyCharsetAndCollation(toCharset, toCollate, origCharset, origCollate, false); err != nil {
 		return doNothing, err

ddl/util/syncer_test.go

@@ -116,16 +116,19 @@ func TestSyncerSimple(t *testing.T) {
 	wg := sync.WaitGroup{}
 	wg.Add(1)
 	currentVer := int64(123)
+	var checkErr string
 	go func() {
 		defer wg.Done()
 		select {
 		case resp := <-d.SchemaSyncer().GlobalVersionCh():
 			if len(resp.Events) < 1 {
-				t.Fatalf("get chan events count less than 1")
+				checkErr = "get chan events count less than 1"
+				return
 			}
 			checkRespKV(t, 1, DDLGlobalSchemaVersion, fmt.Sprintf("%v", currentVer), resp.Events[0].Kv)
 		case <-time.After(3 * time.Second):
-			t.Fatalf("get udpate version failed")
+			checkErr = "get udpate version failed"
+			return
 		}
 	}()
 
@@ -137,6 +140,10 @@ func TestSyncerSimple(t *testing.T) {
 
 	wg.Wait()
 
+	if checkErr != "" {
+		t.Fatalf(checkErr)
+	}
+
 	// for CheckAllVersions
 	childCtx, cancel := goctx.WithTimeout(ctx, 200*time.Millisecond)
 	err = d.SchemaSyncer().OwnerCheckAllVersions(childCtx, currentVer)

executor/insert_common.go

@@ -258,7 +258,6 @@ func insertRows(ctx context.Context, base insertCommon) (err error) {
 	if err != nil {
 		return err
 	}
-	rows = rows[:0]
 	memTracker.Consume(-memUsageOfRows)
 	return nil
 }

executor/set_config.go

@@ -201,7 +201,7 @@ func ConvertConfigItem2JSON(ctx sessionctx.Context, key string, val expression.E
 			str = fmt.Sprintf("%v", f)
 		}
 	case types.ETDecimal:
-		d := new(types.MyDecimal)
+		var d *types.MyDecimal
 		d, isNull, err = val.EvalDecimal(ctx, chunk.Row{})
 		if err == nil && !isNull {
 			str = string(d.ToString())

expression/aggregation/agg_to_pb.go

@@ -26,9 +26,9 @@ import (
 
 // AggFuncToPBExpr converts aggregate function to pb.
 func AggFuncToPBExpr(sc *stmtctx.StatementContext, client kv.Client, aggFunc *AggFuncDesc) *tipb.Expr {
-	if aggFunc.HasDistinct {
-		// do nothing and ignore aggFunc.HasDistinct
-	}
+	// if aggFunc.HasDistinct {
+	// do nothing and ignore aggFunc.HasDistinct
+	// }
 	if len(aggFunc.OrderByItems) > 0 {
 		return nil
 	}

expression/builtin_arithmetic.go

@@ -420,12 +420,12 @@ func (s *builtinArithmeticMinusIntSig) evalInt(row chunk.Row) (val int64, isNull
 	isRHSUnsigned := !forceToSigned && mysql.HasUnsignedFlag(s.args[1].GetType().Flag)
 
 	if forceToSigned && mysql.HasUnsignedFlag(s.args[0].GetType().Flag) {
-		if a < 0 || (a > math.MaxInt64) {
+		if a < 0 {
 			return 0, true, types.ErrOverflow.GenWithStackByArgs("BIGINT UNSIGNED", fmt.Sprintf("(%s - %s)", s.args[0].String(), s.args[1].String()))
 		}
 	}
 	if forceToSigned && mysql.HasUnsignedFlag(s.args[1].GetType().Flag) {
-		if b < 0 || (b > math.MaxInt64) {
+		if b < 0 {
 			return 0, true, types.ErrOverflow.GenWithStackByArgs("BIGINT UNSIGNED", fmt.Sprintf("(%s - %s)", s.args[0].String(), s.args[1].String()))
 		}
 	}

expression/builtin_arithmetic_vec.go

@@ -376,11 +376,11 @@ func (b *builtinArithmeticMinusIntSig) minusFUU(result *chunk.Column, lhi64s, rh
 		}
 		lh, rh := lhi64s[i], rhi64s[i]
 
-		if lh < 0 || (lh > math.MaxInt64) {
+		if lh < 0 {
 			return types.ErrOverflow.GenWithStackByArgs("BIGINT UNSIGNED", fmt.Sprintf("(%s - %s)", b.args[0].String(), b.args[1].String()))
 		}
 
-		if rh < 0 || (rh > math.MaxInt64) {
+		if rh < 0 {
 			return types.ErrOverflow.GenWithStackByArgs("BIGINT UNSIGNED", fmt.Sprintf("(%s - %s)", b.args[0].String(), b.args[1].String()))
 		}
 
@@ -400,7 +400,7 @@ func (b *builtinArithmeticMinusIntSig) minusFUS(result *chunk.Column, lhi64s, rh
 		}
 		lh, rh := lhi64s[i], rhi64s[i]
 
-		if lh < 0 || (lh > math.MaxInt64) {
+		if lh < 0 {
 			return types.ErrOverflow.GenWithStackByArgs("BIGINT UNSIGNED", fmt.Sprintf("(%s - %s)", b.args[0].String(), b.args[1].String()))
 		}
 
@@ -420,7 +420,7 @@ func (b *builtinArithmeticMinusIntSig) minusFSU(result *chunk.Column, lhi64s, rh
 		}
 		lh, rh := lhi64s[i], rhi64s[i]
 
-		if rh < 0 || (rh > math.MaxInt64) {
+		if rh < 0 {
 			return types.ErrOverflow.GenWithStackByArgs("BIGINT UNSIGNED", fmt.Sprintf("(%s - %s)", b.args[0].String(), b.args[1].String()))
 		}
 

expression/builtin_compare.go

@@ -2101,14 +2101,14 @@ func (b *builtinNullEQIntSig) evalInt(row chunk.Row) (val int64, isNull bool, er
 	case !isUnsigned0 && !isUnsigned1 && types.CompareInt64(arg0, arg1) == 0:
 		res = 1
 	case isUnsigned0 && !isUnsigned1:
-		if arg1 < 0 || arg0 > math.MaxInt64 {
+		if arg1 < 0 {
 			break
 		}
 		if types.CompareInt64(arg0, arg1) == 0 {
 			res = 1
 		}
 	case !isUnsigned0 && isUnsigned1:
-		if arg0 < 0 || arg1 > math.MaxInt64 {
+		if arg0 < 0 {
 			break
 		}
 		if types.CompareInt64(arg0, arg1) == 0 {

expression/builtin_vectorized_test.go

@@ -784,8 +784,6 @@ func (s *testEvaluatorSuite) TestFloat32ColVec(c *C) {
 		i++
 	}
 
-	// set an empty Sel
-	sel = sel[:0]
 	c.Assert(col.VecEvalReal(ctx, chk, result), IsNil)
 }
 

expression/chunk_executor.go

@@ -137,10 +137,10 @@ func evalOneVec(ctx sessionctx.Context, expr Expression, input *chunk.Chunk, out
 			}
 			// TODO: recycle all old Columns returned here.
 			output.SetCol(colIdx, buf)
-		} else if mysql.HasUnsignedFlag(ft.Flag) {
-			// the underlying memory formats of int64 and uint64 are the same in Golang,
-			// so we can do a no-op here.
-		}
+		} // else if mysql.HasUnsignedFlag(ft.Flag) {
+		// the underlying memory formats of int64 and uint64 are the same in Golang,
+		// so we can do a no-op here.
+		// }
 	case types.ETReal:
 		if err := expr.VecEvalReal(ctx, input, result); err != nil {
 			return err

planner/core/memtable_predicate_extractor.go

@@ -854,9 +854,9 @@ func (e *InspectionSummaryTableExtractor) Extract(
 	predicates []expression.Expression,
 ) (remained []expression.Expression) {
 	// Extract the `rule` columns
-	remained, ruleSkip, rules := e.extractCol(schema, names, predicates, "rule", true)
+	_, ruleSkip, rules := e.extractCol(schema, names, predicates, "rule", true)
 	// Extract the `metric_name` columns
-	remained, metricNameSkip, metricNames := e.extractCol(schema, names, predicates, "metrics_name", true)
+	_, metricNameSkip, metricNames := e.extractCol(schema, names, predicates, "metrics_name", true)
 	// Extract the `quantile` columns
 	remained, quantileSkip, quantileSet := e.extractCol(schema, names, predicates, "quantile", false)
 	e.SkipInspection = ruleSkip || quantileSkip || metricNameSkip

session/schema_amender.go

@@ -475,9 +475,7 @@ func (s *SchemaAmender) getAmendableKeys(commitMutations tikv.CommitterMutations
 			addKeys = append(addKeys, byteKey)
 		} else if pb.Op_Del == keyOp {
 			removeKeys = append(removeKeys, byteKey)
-		} else {
-			// Do nothing.
-		}
+		} // else Do nothing.
 	}
 	return addKeys, removeKeys
 }

session/session_test.go

@@ -542,9 +542,9 @@ func testTxnLazyInitialize(s *testSessionSuite, c *C, isPessimistic bool) {
 	}
 
 	tk.MustExec("set @@autocommit = 0")
-	txn, err := tk.Se.Txn(true)
+	_, err := tk.Se.Txn(true)
 	c.Assert(kv.ErrInvalidTxn.Equal(err), IsTrue)
-	txn, err = tk.Se.Txn(false)
+	txn, err := tk.Se.Txn(false)
 	c.Assert(err, IsNil)
 	c.Assert(txn.Valid(), IsFalse)
 	tk.MustQuery("select @@tidb_current_ts").Check(testkit.Rows("0"))

table/tables/tables_test.go

@@ -587,7 +587,7 @@ func (ts *testSuite) TestAddRecordWithCtx(c *C) {
 	defer ts.se.Execute(context.Background(), "DROP TABLE test.tRecord")
 
 	c.Assert(ts.se.NewTxn(context.Background()), IsNil)
-	txn, err := ts.se.Txn(true)
+	_, err = ts.se.Txn(true)
 	c.Assert(err, IsNil)
 	recordCtx := tables.NewCommonAddRecordCtx(len(tb.Cols()))
 	tables.SetAddRecordCtx(ts.se, recordCtx)
@@ -612,7 +612,7 @@ func (ts *testSuite) TestAddRecordWithCtx(c *C) {
 	c.Assert(i, Equals, len(records))
 
 	ts.se.StmtCommit()
-	txn, err = ts.se.Txn(true)
+	txn, err := ts.se.Txn(true)
 	c.Assert(err, IsNil)
 	c.Assert(txn.Commit(context.Background()), IsNil)
 }

util/plancodec/id.go

@@ -110,45 +110,45 @@ const (
 // Attention: for compatibility of encode/decode plan, The plan id shouldn't be changed.
 const (
 	typeSelID                 int = 1
-	typeSetID                     = 2
-	typeProjID                    = 3
-	typeAggID                     = 4
-	typeStreamAggID               = 5
-	typeHashAggID                 = 6
-	typeShowID                    = 7
-	typeJoinID                    = 8
-	typeUnionID                   = 9
-	typeTableScanID               = 10
-	typeMemTableScanID            = 11
-	typeUnionScanID               = 12
-	typeIdxScanID                 = 13
-	typeSortID                    = 14
-	typeTopNID                    = 15
-	typeLimitID                   = 16
-	typeHashJoinID                = 17
-	typeMergeJoinID               = 18
-	typeIndexJoinID               = 19
-	typeIndexMergeJoinID          = 20
-	typeIndexHashJoinID           = 21
-	typeApplyID                   = 22
-	typeMaxOneRowID               = 23
-	typeExistsID                  = 24
-	typeDualID                    = 25
-	typeLockID                    = 26
-	typeInsertID                  = 27
-	typeUpdateID                  = 28
-	typeDeleteID                  = 29
-	typeIndexLookUpID             = 30
-	typeTableReaderID             = 31
-	typeIndexReaderID             = 32
-	typeWindowID                  = 33
-	typeTiKVSingleGatherID        = 34
-	typeIndexMergeID              = 35
-	typePointGet                  = 36
-	typeShowDDLJobs               = 37
-	typeBatchPointGet             = 38
-	typeClusterMemTableReader     = 39
-	typeDataSourceID              = 40
+	typeSetID                 int = 2
+	typeProjID                int = 3
+	typeAggID                 int = 4
+	typeStreamAggID           int = 5
+	typeHashAggID             int = 6
+	typeShowID                int = 7
+	typeJoinID                int = 8
+	typeUnionID               int = 9
+	typeTableScanID           int = 10
+	typeMemTableScanID        int = 11
+	typeUnionScanID           int = 12
+	typeIdxScanID             int = 13
+	typeSortID                int = 14
+	typeTopNID                int = 15
+	typeLimitID               int = 16
+	typeHashJoinID            int = 17
+	typeMergeJoinID           int = 18
+	typeIndexJoinID           int = 19
+	typeIndexMergeJoinID      int = 20
+	typeIndexHashJoinID       int = 21
+	typeApplyID               int = 22
+	typeMaxOneRowID           int = 23
+	typeExistsID              int = 24
+	typeDualID                int = 25
+	typeLockID                int = 26
+	typeInsertID              int = 27
+	typeUpdateID              int = 28
+	typeDeleteID              int = 29
+	typeIndexLookUpID         int = 30
+	typeTableReaderID         int = 31
+	typeIndexReaderID         int = 32
+	typeWindowID              int = 33
+	typeTiKVSingleGatherID    int = 34
+	typeIndexMergeID          int = 35
+	typePointGet              int = 36
+	typeShowDDLJobs           int = 37
+	typeBatchPointGet         int = 38
+	typeClusterMemTableReader int = 39
+	typeDataSourceID          int = 40
 )
 
 // TypeStringToPhysicalID converts the plan type string to plan id.

util/testutil/testutil.go

@@ -366,7 +366,7 @@ func (t *TestData) ConvertRowsToStrings(rows [][]interface{}) (rs []string) {
 // ConvertSQLWarnToStrings converts []SQLWarn to []string.
 func (t *TestData) ConvertSQLWarnToStrings(warns []stmtctx.SQLWarn) (rs []string) {
 	for _, warn := range warns {
-		rs = append(rs, fmt.Sprintf(warn.Err.Error()))
+		rs = append(rs, fmt.Sprint(warn.Err.Error()))
 	}
 	return rs
 }