fix: do not remove empty openid teams when none are present

Maybe resolves https://community.vikunja.io/t/empty-openid-team-cleanup-cron-error-removing-empty-openid-team-database-is-locked-error-when-exporting-data/2306/3

pkg/caldav/parsing.go

@@ -95,6 +95,9 @@ func ParseTaskFromVTODO(content string) (vTask *models.Task, err error) {
 	if err != nil {
 		return nil, err
 	}
+	if len(parsed.Components) == 0 {
+		return nil, errors.New("VTODO element does seem not contain any components")
+	}
 	vTodo, ok := parsed.Components[0].(*ics.VTodo)
 	if !ok {
 		return nil, errors.New("VTODO element not found")

pkg/modules/auth/openid/cron.go

@@ -38,6 +38,10 @@ func RemoveEmptySSOTeams(s *xorm.Session) (err error) {
 		return err
 	}
 
+	if len(teams) == 0 {
+		return nil
+	}
+
 	teamIDs := make([]int64, 0, len(teams))
 	for _, team := range teams {
 		teamIDs = append(teamIDs, team.ID)
@@ -63,6 +67,6 @@ func RegisterEmptyOpenIDTeamCleanupCron() {
 		}
 	})
 	if err != nil {
-		log.Fatalf("Could not empty openid teams cleanup cron: %s", err)
+		log.Fatalf("Could not register empty openid teams cleanup cron: %s", err)
 	}
 }

pkg/routes/caldav/listStorageProvider.go

@@ -636,7 +636,7 @@ func (vcls *VikunjaCaldavProjectStorage) getProjectRessource(isCollection bool)
 		tk := models.TaskCollection{
 			ProjectID: vcls.project.ID,
 		}
-		iface, _, _, err := tk.ReadAll(s, vcls.user, "", 1, 1000)
+		iface, _, _, err := tk.ReadAll(s, vcls.user, "", 0, -1)
 		if err != nil {
 			_ = s.Rollback()
 			return rr, err