fix(datastore): loading civil types in non UTC location is incorrect

datastore/load.go

@@ -384,13 +384,13 @@ func setVal(v reflect.Value, p Property) (s string) {
 			}
 			v.Set(reflect.ValueOf(x))
 		case typeOfCivilDate:
-			date := civil.DateOf(pValue.(time.Time))
+			date := civil.DateOf(pValue.(time.Time).In(time.UTC))
 			v.Set(reflect.ValueOf(date))
 		case typeOfCivilDateTime:
-			dateTime := civil.DateTimeOf(pValue.(time.Time))
+			dateTime := civil.DateTimeOf(pValue.(time.Time).In(time.UTC))
 			v.Set(reflect.ValueOf(dateTime))
 		case typeOfCivilTime:
-			timeVal := civil.TimeOf(pValue.(time.Time))
+			timeVal := civil.TimeOf(pValue.(time.Time).In(time.UTC))
 			v.Set(reflect.ValueOf(timeVal))
 		default:
 			ent, ok := pValue.(*Entity)

datastore/load_test.go

@@ -439,6 +439,42 @@ type withUntypedInterface struct {
 	Field interface{}
 }
 
+func TestLoadCivilTimeInNonUTCZone(t *testing.T) {
+	src := &pb.Entity{
+		Key: keyToProto(testKey0),
+		Properties: map[string]*pb.Value{
+			"Time": {ValueType: &pb.Value_TimestampValue{TimestampValue: &timestamppb.Timestamp{Seconds: 1605504600}}},
+		},
+	}
+	dst := &struct{ Time civil.Time }{
+		Time: civil.Time{},
+	}
+	want := &struct{ Time civil.Time }{
+		Time: civil.Time{
+			Hour:   5,
+			Minute: 30,
+		},
+	}
+	loc, err := time.LoadLocation("Africa/Cairo")
+	if err != nil {
+		t.Fatalf("LoadLocation: %v", err)
+	}
+	time.Local = loc
+
+	err = loadEntityProto(dst, src)
+	if err != nil {
+		t.Fatalf("loadEntityProto: %v", err)
+	}
+	if diff := testutil.Diff(dst, want); diff != "" {
+		t.Fatalf("Mismatch: got - want +\n%s", diff)
+	}
+	loc, err = time.LoadLocation("UTC")
+	if err != nil {
+		t.Fatalf("LoadLocation: %v", err)
+	}
+	time.Local = loc
+}
+
 func TestLoadToInterface(t *testing.T) {
 	testCases := []struct {
 		name    string