No default students

class.go

@@ -40,7 +40,7 @@ func (c Class) tagsMatch(t time.Time) bool {
 	return true
 }
 
-func (c Class) buildEvent(t time.Time) *calendar.Event {
+func (c Class) buildEvent(t time.Time) (*calendar.Event, error) {
 	dateStr := t.Format("2006-01-02")
 
 	ev := &calendar.Event{
@@ -56,12 +56,11 @@ func (c Class) buildEvent(t time.Time) *calendar.Event {
 		Attendees: []*calendar.EventAttendee{},
 	}
 
-	attendees := c.Students
-	if len(attendees) == 0 {
-		attendees = allStudents
+	if len(c.Students) == 0 {
+		return nil, fmt.Errorf("class with no students: %s", c.Summary)
 	}
 
-	for _, student := range attendees {
+	for _, student := range c.Students {
 		ev.Attendees = append(
 			ev.Attendees,
 			&calendar.EventAttendee{
@@ -74,5 +73,5 @@ func (c Class) buildEvent(t time.Time) *calendar.Event {
 		ev.Description = fmt.Sprintf(`Zoom: %s`, c.Zoom)
 	}
 
-	return ev
+	return ev, nil
 }