Cherry-pick 5468f5d

Signed-off-by: Dirkjan Bussink <[email protected]>

go/vt/vtgate/engine/fake_vcursor_test.go

@@ -140,7 +140,7 @@ func (t *noopVCursor) Environment() *vtenv.Environment {
 }
 
 func (t *noopVCursor) TimeZone() *time.Location {
-	return nil
+	return time.Local
 }
 
 func (t *noopVCursor) SQLMode() string {

go/vt/vtgate/evalengine/fn_time.go

@@ -242,7 +242,7 @@ func (call *builtinNow) constant() bool {
 
 func (call *builtinSysdate) eval(env *ExpressionEnv) (eval, error) {
 	now := SystemTime()
-	if tz := env.currentTimezone(); tz != nil {
+	if tz := env.currentTimezone(); tz != time.Local {
 		now = now.In(tz)
 	}
 	return newEvalDateTime(datetime.NewDateTimeFromStd(now), int(call.prec), false), nil
@@ -687,7 +687,7 @@ func (b *builtinFromUnixtime) eval(env *ExpressionEnv) (eval, error) {
 	}
 
 	t := time.Unix(sec, frac)
-	if tz := env.currentTimezone(); tz != nil {
+	if tz := env.currentTimezone(); tz != time.Local {
 		t = t.In(tz)
 	}
 

go/vt/vtgate/safe_session.go

@@ -26,7 +26,7 @@ import (
 	"google.golang.org/protobuf/proto"
 
 	"vitess.io/vitess/go/mysql/datetime"
-
+	"vitess.io/vitess/go/sqltypes"
 	"vitess.io/vitess/go/vt/sqlparser"
 	"vitess.io/vitess/go/vt/srvtopo"
 	"vitess.io/vitess/go/vt/sysvars"
@@ -563,13 +563,22 @@ func (session *SafeSession) HasSystemVariables() (found bool) {
 
 func (session *SafeSession) TimeZone() *time.Location {
 	session.mu.Lock()
-	tz, ok := session.SystemVariables["time_zone"]
+	zoneSQL, ok := session.SystemVariables["time_zone"]
 	session.mu.Unlock()
 
 	if !ok {
-		return nil
+		return time.Local
+	}
+
+	tz, err := sqltypes.DecodeStringSQL(zoneSQL)
+	if err != nil {
+		return time.Local
+	}
+
+	loc, err := datetime.ParseTimeZone(tz)
+	if err != nil {
+		return time.Local
 	}
-	loc, _ := datetime.ParseTimeZone(tz)
 	return loc
 }
 

go/vt/vtgate/safe_session_test.go

@@ -73,25 +73,31 @@ func TestTimeZone(t *testing.T) {
 		want string
 	}{
 		{
-			tz:   "Europe/Amsterdam",
+			tz:   "",
+			want: time.Local.String(),
+		},
+		{
+			tz:   "'Europe/Amsterdam'",
 			want: "Europe/Amsterdam",
 		},
 		{
-			tz:   "+02:00",
+			tz:   "'+02:00'",
 			want: "UTC+02:00",
 		},
 		{
 			tz:   "foo",
-			want: (*time.Location)(nil).String(),
+			want: time.Local.String(),
 		},
 	}
 
 	for _, tc := range testCases {
 		t.Run(tc.tz, func(t *testing.T) {
+			sysvars := map[string]string{}
+			if tc.tz != "" {
+				sysvars["time_zone"] = tc.tz
+			}
 			session := NewSafeSession(&vtgatepb.Session{
-				SystemVariables: map[string]string{
-					"time_zone": tc.tz,
-				},
+				SystemVariables: sysvars,
 			})
 
 			assert.Equal(t, tc.want, session.TimeZone().String())