expression: fix week func format (#9685)

expression/builtin_time.go

@@ -31,6 +31,7 @@ import (
 	"github.com/pingcap/parser/terror"
 	"github.com/pingcap/tidb/sessionctx"
 	"github.com/pingcap/tidb/sessionctx/stmtctx"
+	"github.com/pingcap/tidb/sessionctx/variable"
 	"github.com/pingcap/tidb/types"
 	"github.com/pingcap/tidb/util/chunk"
 	"github.com/pingcap/tipb/go-tipb"
@@ -1284,7 +1285,16 @@ func (b *builtinWeekWithoutModeSig) evalInt(row chunk.Row) (int64, bool, error)
 		return 0, true, errors.Trace(handleInvalidTimeError(b.ctx, types.ErrIncorrectDatetimeValue.GenWithStackByArgs(date.String())))
 	}
 
-	week := date.Time.Week(0)
+	mode := 0
+	modeStr, ok := b.ctx.GetSessionVars().GetSystemVar(variable.DefaultWeekFormat)
+	if ok && modeStr != "" {
+		mode, err = strconv.Atoi(modeStr)
+		if err != nil {
+			return 0, true, handleInvalidTimeError(b.ctx, types.ErrInvalidWeekModeFormat.GenWithStackByArgs(modeStr))
+		}
+	}
+
+	week := date.Time.Week(mode)
 	return int64(week), false, nil
 }
 

expression/builtin_time_test.go

@@ -1456,9 +1456,35 @@ func (s *testEvaluatorSuite) TestWeek(c *C) {
 		c.Assert(err, IsNil)
 		c.Assert(result.GetInt64(), Equals, test.expect)
 	}
-
 }
 
+func (s *testEvaluatorSuite) TestWeekWithoutModeSig(c *C) {
+	tests := []struct {
+		t      string
+		expect int64
+	}{
+		{"2008-02-20", 7},
+		{"2000-12-31", 53},
+		{"2000-12-31", 1}, //set default week mode
+		{"2005-12-3", 48}, //set default week mode
+		{"2008-02-20", 7},
+	}
+
+	fc := funcs[ast.Week]
+	for i, test := range tests {
+		arg1 := types.NewStringDatum(test.t)
+		f, err := fc.getFunction(s.ctx, s.datumsToConstants([]types.Datum{arg1}))
+		c.Assert(err, IsNil)
+		result, err := evalBuiltinFunc(f, chunk.Row{})
+		c.Assert(err, IsNil)
+		c.Assert(result.GetInt64(), Equals, test.expect)
+		if i == 1 {
+			s.ctx.GetSessionVars().SetSystemVar("default_week_format", "6")
+		} else if i == 3 {
+			s.ctx.GetSessionVars().SetSystemVar("default_week_format", "")
+		}
+	}
+}
 func (s *testEvaluatorSuite) TestYearWeek(c *C) {
 	sc := s.ctx.GetSessionVars().StmtCtx
 	sc.IgnoreZeroInDate = true

expression/errors.go

@@ -68,7 +68,8 @@ func init() {
 
 // handleInvalidTimeError reports error or warning depend on the context.
 func handleInvalidTimeError(ctx sessionctx.Context, err error) error {
-	if err == nil || !(terror.ErrorEqual(err, types.ErrInvalidTimeFormat) || types.ErrIncorrectDatetimeValue.Equal(err) || types.ErrTruncatedWrongValue.Equal(err)) {
+	if err == nil || !(terror.ErrorEqual(err, types.ErrInvalidTimeFormat) || types.ErrIncorrectDatetimeValue.Equal(err) ||
+		types.ErrTruncatedWrongValue.Equal(err) || types.ErrInvalidWeekModeFormat.Equal(err)) {
 		return err
 	}
 	sc := ctx.GetSessionVars().StmtCtx

types/time.go

@@ -33,6 +33,7 @@ import (
 // Portable analogs of some common call errors.
 var (
 	ErrInvalidTimeFormat      = terror.ClassTypes.New(mysql.ErrTruncatedWrongValue, "invalid time format: '%v'")
+	ErrInvalidWeekModeFormat  = terror.ClassTypes.New(mysql.ErrTruncatedWrongValue, "invalid week mode format: '%v'")
 	ErrInvalidYearFormat      = errors.New("invalid year format")
 	ErrInvalidYear            = errors.New("invalid year")
 	ErrZeroDate               = errors.New("datetime zero in date")