iTIP: Do not send a REPLY when deleting an event that was not accepted

crates/groupware/src/calendar/storage.rs

@@ -391,7 +391,7 @@ impl DestroyArchive<Archive<&ArchivedCalendarEvent>> {
                         .caused_by(trc::location!())?;
 
                     if let Ok(messages) =
-                        itip_cancel(&event.data.event, access_token.emails.as_slice())
+                        itip_cancel(&event.data.event, access_token.emails.as_slice(), true)
                     {
                         ItipMessages::new(vec![messages])
                             .queue(batch)

crates/groupware/src/scheduling/attendee.rs

@@ -59,6 +59,7 @@ pub(crate) fn attendee_handle_update(
                                     old_instance,
                                     &dt_stamp,
                                     &mut email_rcpt,
+                                    false,
                                 ) {
                                     // Add EXDATE as RECURRENCE-ID
                                     cancel_comp
@@ -207,6 +208,7 @@ pub(crate) fn attendee_handle_update(
                     old_instance,
                     &dt_stamp,
                     &mut email_rcpt,
+                    false,
                 ) {
                     // Add cancel component
                     let comp_id = message.components.len() as u16;
@@ -269,6 +271,7 @@ pub(crate) fn attendee_decline<'x>(
     comp: &'x ItipSnapshot<'x>,
     dt_stamp: &'x PartialDateTime,
     email_rcpt: &mut AHashSet<&'x str>,
+    skip_needs_action: bool,
 ) -> Option<(ICalendarComponent, &'x Email)> {
     let component = comp.comp;
     let mut cancel_comp = ICalendarComponent {
@@ -284,14 +287,14 @@ pub(crate) fn attendee_decline<'x>(
         if attendee.email.is_local {
             if attendee.is_server_scheduling
                 && attendee.rsvp.is_none_or(|rsvp| rsvp)
-                && (attendee.force_send.is_some()
-                    || !matches!(
-                        attendee.part_stat,
-                        Some(
-                            ICalendarParticipationStatus::Declined
-                                | ICalendarParticipationStatus::Delegated
-                        )
-                    ))
+                && match attendee.part_stat {
+                    Some(
+                        ICalendarParticipationStatus::Declined
+                        | ICalendarParticipationStatus::Delegated,
+                    ) => attendee.force_send.is_some(),
+                    Some(ICalendarParticipationStatus::NeedsAction) => !skip_needs_action,
+                    _ => true,
+                }
             {
                 local_attendee = Some(attendee);
             }

crates/groupware/src/scheduling/event_cancel.rs

@@ -22,6 +22,7 @@ use calcard::{
 pub fn itip_cancel(
     ical: &ICalendar,
     account_emails: &[String],
+    is_deletion: bool,
 ) -> Result<ItipMessage<ICalendar>, ItipError> {
     // Prepare iTIP message
     let itip = itip_snapshot(ical, account_emails, false)?;
@@ -88,9 +89,14 @@ pub fn itip_cancel(
         let mut mail_from = None;
         let mut email_rcpt = AHashSet::new();
         for (instance_id, comp) in &itip.components {
-            if let Some((cancel_comp, attendee_email)) =
-                attendee_decline(instance_id, &itip, comp, &dt_stamp, &mut email_rcpt)
-            {
+            if let Some((cancel_comp, attendee_email)) = attendee_decline(
+                instance_id,
+                &itip,
+                comp,
+                &dt_stamp,
+                &mut email_rcpt,
+                is_deletion,
+            ) {
                 // Add cancel component
                 let comp_id = message.components.len() as u16;
                 message.components[0].component_ids.push(comp_id);

crates/groupware/src/scheduling/event_update.rs

@@ -39,7 +39,7 @@ pub fn itip_update(
                 | ItipError::OtherSchedulingAgent => {
                     if old_itip.organizer.email.is_local {
                         // RFC 6638 does not support replacing the organizer, so we cancel the event
-                        itip_cancel(old_ical, account_emails).map(|message| vec![message])
+                        itip_cancel(old_ical, account_emails, false).map(|message| vec![message])
                     } else {
                         Err(ItipError::CannotModifyAddress)
                     }