Make the parsing of pgtype.Time stricter and add tests

pgtype/time.go

@@ -45,7 +45,12 @@ func (t *Time) Scan(src any) error {
 
 	switch src := src.(type) {
 	case string:
-		return scanPlanTextAnyToTimeScanner{}.Scan([]byte(src), t)
+		err := scanPlanTextAnyToTimeScanner{}.Scan([]byte(src), t)
+		if err != nil {
+			t.Microseconds = 0
+			t.Valid = false
+		}
+		return err
 	}
 
 	return fmt.Errorf("cannot scan %T", src)
@@ -176,7 +181,7 @@ func (scanPlanTextAnyToTimeScanner) Scan(src []byte, dst any) error {
 
 	s := string(src)
 
-	if len(s) < 8 {
+	if len(s) < 8 || s[2] != ':' || s[5] != ':' {
 		return fmt.Errorf("cannot decode %v into Time", s)
 	}
 
@@ -199,6 +204,10 @@ func (scanPlanTextAnyToTimeScanner) Scan(src []byte, dst any) error {
 	usec += seconds * microsecondsPerSecond
 
 	if len(s) > 9 {
+		if s[8] != '.' || len(s) > 15 {
+			return fmt.Errorf("cannot decode %v into Time", s)
+		}
+
 		fraction := s[9:]
 		n, err := strconv.ParseInt(fraction, 10, 64)
 		if err != nil {

pgtype/time_test.go

@@ -2,11 +2,13 @@ package pgtype_test
 
 import (
 	"context"
+	"strconv"
 	"testing"
 	"time"
 
 	"github.com/jackc/pgx/v5/pgtype"
 	"github.com/jackc/pgx/v5/pgxtest"
+	"github.com/stretchr/testify/assert"
 )
 
 func TestTimeCodec(t *testing.T) {
@@ -45,3 +47,69 @@ func TestTimeCodec(t *testing.T) {
 		{nil, new(pgtype.Time), isExpectedEq(pgtype.Time{})},
 	})
 }
+
+func TestTimeTextScanner(t *testing.T) {
+	var pgTime pgtype.Time
+
+	assert.NoError(t, pgTime.Scan("07:37:16"))
+	assert.Equal(t, true, pgTime.Valid)
+	assert.Equal(t, int64(7*time.Hour+37*time.Minute+16*time.Second), pgTime.Microseconds*int64(time.Microsecond))
+
+	assert.NoError(t, pgTime.Scan("15:04:05"))
+	assert.Equal(t, true, pgTime.Valid)
+	assert.Equal(t, int64(15*time.Hour+4*time.Minute+5*time.Second), pgTime.Microseconds*int64(time.Microsecond))
+
+	// parsing of fractional digits
+	assert.NoError(t, pgTime.Scan("15:04:05.00"))
+	assert.Equal(t, true, pgTime.Valid)
+	assert.Equal(t, int64(15*time.Hour+4*time.Minute+5*time.Second), pgTime.Microseconds*int64(time.Microsecond))
+
+	const mirco = "789123"
+	const woFraction = int64(4*time.Hour + 5*time.Minute + 6*time.Second) // time without fraction
+	for i := 0; i <= len(mirco); i++ {
+		assert.NoError(t, pgTime.Scan("04:05:06."+mirco[:i]))
+		assert.Equal(t, true, pgTime.Valid)
+
+		frac, _ := strconv.ParseInt(mirco[:i], 10, 64)
+		for k := i; k < 6; k++ {
+			frac *= 10
+		}
+		assert.Equal(t, woFraction+frac*int64(time.Microsecond), pgTime.Microseconds*int64(time.Microsecond))
+	}
+
+	// parsing of too long fraction errors
+	assert.Error(t, pgTime.Scan("04:05:06.7891234"))
+	assert.Equal(t, false, pgTime.Valid)
+	assert.Equal(t, int64(0), pgTime.Microseconds)
+
+	// parsing of timetz errors
+	assert.Error(t, pgTime.Scan("04:05:06.789-08"))
+	assert.Equal(t, false, pgTime.Valid)
+	assert.Equal(t, int64(0), pgTime.Microseconds)
+
+	assert.Error(t, pgTime.Scan("04:05:06-08:00"))
+	assert.Equal(t, false, pgTime.Valid)
+	assert.Equal(t, int64(0), pgTime.Microseconds)
+
+	// parsing of date errors
+	assert.Error(t, pgTime.Scan("1997-12-17"))
+	assert.Equal(t, false, pgTime.Valid)
+	assert.Equal(t, int64(0), pgTime.Microseconds)
+
+	// parsing of text errors
+	assert.Error(t, pgTime.Scan("12345678"))
+	assert.Equal(t, false, pgTime.Valid)
+	assert.Equal(t, int64(0), pgTime.Microseconds)
+
+	assert.Error(t, pgTime.Scan("12-34-56"))
+	assert.Equal(t, false, pgTime.Valid)
+	assert.Equal(t, int64(0), pgTime.Microseconds)
+
+	assert.Error(t, pgTime.Scan("12:34-56"))
+	assert.Equal(t, false, pgTime.Valid)
+	assert.Equal(t, int64(0), pgTime.Microseconds)
+
+	assert.Error(t, pgTime.Scan("12-34:56"))
+	assert.Equal(t, false, pgTime.Valid)
+	assert.Equal(t, int64(0), pgTime.Microseconds)
+}