fix(calendar-sync): drop singly-declined recurring occurrences

Declining one occurrence of a recurring meeting left it on the agenda. Google emits that decline as a RECURRENCE-ID override carrying the user's PARTSTAT=DECLINED. But calendar-sync--parse-exception-event never read the override's attendee block, so the occurrence kept the series' inherited "accepted" status and the declined filter never dropped it. The apply side already re-derives status from an override's attendees. The parse side just wasn't supplying them.

The fix parses the override's ATTENDEE lines into :attendees, the same way parse-event does. A unit test covers the extraction. An integration test runs the full parse/apply/filter chain on a declined week.

3 files changed, 83 insertions, 3 deletions

diff --git a/modules/calendar-sync-recurrence.el b/modules/calendar-sync-recurrence.el
index d4f70b7d1..72576a6f7 100644
--- a/modules/calendar-sync-recurrence.el
+++ b/modules/calendar-sync-recurrence.el
@@ -51,7 +51,15 @@ Returns nil if not found."
   "Parse a RECURRENCE-ID override EVENT-STR into an exception plist, or nil.
 Returns nil when EVENT-STR carries no RECURRENCE-ID, or its recurrence-id /
 start time fail to parse.  The plist holds :recurrence-id (localized),
-:recurrence-id-raw, :start, :end, :summary, :description, :location."
+:recurrence-id-raw, :start, :end, :summary, :description, :location,
+:attendees.
+
+:attendees is carried so `calendar-sync--apply-single-exception' can
+re-derive the user's status when a single occurrence is declined: a
+RECURRENCE-ID override is exactly how a calendar marks one occurrence of a
+recurring series declined, and without the attendee block here the override
+inherits the series' \"accepted\" status and the declined occurrence is never
+dropped by `calendar-sync--filter-declined'."
   (let ((recurrence-id (calendar-sync--get-recurrence-id event-str)))
     (when recurrence-id
       (let* ((recurrence-id-line (calendar-sync--get-recurrence-id-line event-str))
@@ -72,7 +80,12 @@ start time fail to parse.  The plist holds :recurrence-id (localized),
              (description (calendar-sync--clean-text
                            (calendar-sync--get-property event-str "DESCRIPTION")))
              (location (calendar-sync--clean-text
-                        (calendar-sync--get-property event-str "LOCATION"))))
+                        (calendar-sync--get-property event-str "LOCATION")))
+             ;; Carry the override's attendee block so a singly-declined
+             ;; occurrence can re-derive the user's status downstream.
+             (attendee-lines (calendar-sync--get-all-property-lines event-str "ATTENDEE"))
+             (attendees (delq nil (mapcar #'calendar-sync--parse-attendee-line
+                                          attendee-lines))))
         (when (and recurrence-id-parsed start-parsed)
           (list :recurrence-id (calendar-sync--localize-parsed-datetime
                                 recurrence-id-parsed recurrence-id-is-utc recurrence-id-tzid)
@@ -81,7 +94,8 @@ start time fail to parse.  The plist holds :recurrence-id (localized),
                 :end end-parsed
                 :summary summary
                 :description description
-                :location location))))))
+                :location location
+                :attendees attendees))))))
 
 (defun calendar-sync--collect-recurrence-exceptions (ics-content)
   "Collect all RECURRENCE-ID events from ICS-CONTENT.
diff --git a/tests/test-calendar-sync--parse-exception-event.el b/tests/test-calendar-sync--parse-exception-event.el
index 1935d3ebb..a26a7418c 100644
--- a/tests/test-calendar-sync--parse-exception-event.el
+++ b/tests/test-calendar-sync--parse-exception-event.el
@@ -47,6 +47,28 @@
          (event (test-calendar-sync-make-vevent "Regular Event" start end)))
     (should-not (calendar-sync--parse-exception-event event))))
 
+;;; Normal Cases — attendee extraction (singly-declined occurrence)
+
+(ert-deftest test-calendar-sync--parse-exception-event-extracts-attendees ()
+  "Normal: a RECURRENCE-ID override carrying an ATTENDEE block parses :attendees,
+so a singly-declined occurrence can have its user status re-derived downstream
+by `calendar-sync--apply-single-exception'."
+  (let* ((start (test-calendar-sync-time-days-from-now 7 10 0))
+         (end (test-calendar-sync-time-days-from-now 7 11 0))
+         (event (concat "BEGIN:VEVENT\n"
+                        "UID:override@google.com\n"
+                        "RECURRENCE-ID:20260203T090000Z\n"
+                        "SUMMARY:1:1 with Hayk\n"
+                        "ATTENDEE;CN=Craig;PARTSTAT=DECLINED:mailto:craig@example.com\n"
+                        "DTSTART:" (test-calendar-sync-ics-datetime start) "\n"
+                        "DTEND:" (test-calendar-sync-ics-datetime end) "\n"
+                        "END:VEVENT"))
+         (plist (calendar-sync--parse-exception-event event))
+         (attendees (plist-get plist :attendees)))
+    (should attendees)
+    (should (equal "craig@example.com" (plist-get (car attendees) :email)))
+    (should (equal "DECLINED" (plist-get (car attendees) :partstat)))))
+
 ;;; Error Cases
 
 (ert-deftest test-calendar-sync--parse-exception-event-error-unparseable-times ()
diff --git a/tests/test-integration-calendar-sync-recurrence-exceptions.el b/tests/test-integration-calendar-sync-recurrence-exceptions.el
index 0a9b5af1f..dde0603a2 100644
--- a/tests/test-integration-calendar-sync-recurrence-exceptions.el
+++ b/tests/test-integration-calendar-sync-recurrence-exceptions.el
@@ -162,5 +162,49 @@ Weekly meeting with one instance rescheduled from 09:00 to 10:00."
     (should (string-match-p "10:00" org-output))
     (should (string-match-p "15:00" org-output))))
 
+(ert-deftest test-integration-declined-single-occurrence-is-dropped ()
+  "A recurring event with one occurrence declined via a RECURRENCE-ID override
+is filtered out end-to-end, while the other occurrences survive.
+
+This is the singly-declined-occurrence case: declining one instance of a series
+in Google Calendar emits a RECURRENCE-ID override carrying the user's
+PARTSTAT=DECLINED.  The override must carry its attendee block all the way from
+`calendar-sync--parse-exception-event' through
+`calendar-sync--apply-single-exception' (status re-derivation) to
+`calendar-sync--filter-declined' for the drop to happen."
+  (let* ((calendar-sync-skip-declined t)
+         (calendar-sync-user-emails '("craig@example.com"))
+         (base-start (test-calendar-sync-time-days-from-now 0 9 0))
+         (base-end (test-calendar-sync-time-days-from-now 0 10 0))
+         (rec-id (test-calendar-sync-time-days-from-now 7 9 0))
+         (decl-start (test-calendar-sync-time-days-from-now 7 9 0))
+         (decl-end (test-calendar-sync-time-days-from-now 7 10 0))
+         (ics-content
+          (concat "BEGIN:VCALENDAR\n"
+                  "VERSION:2.0\n"
+                  "BEGIN:VEVENT\n"
+                  "UID:1on1@google.com\n"
+                  "SUMMARY:1on1 with Hayk\n"
+                  "DTSTART:" (test-calendar-sync-ics-datetime-local base-start) "\n"
+                  "DTEND:" (test-calendar-sync-ics-datetime-local base-end) "\n"
+                  "RRULE:FREQ=WEEKLY;COUNT=4\n"
+                  "END:VEVENT\n"
+                  ;; Week 2 declined: RECURRENCE-ID override with PARTSTAT=DECLINED
+                  "BEGIN:VEVENT\n"
+                  "UID:1on1@google.com\n"
+                  "RECURRENCE-ID:" (test-calendar-sync-ics-datetime-local rec-id) "\n"
+                  "SUMMARY:1on1 with Hayk DECLINEDWEEK\n"
+                  "ATTENDEE;CN=Craig;PARTSTAT=DECLINED:mailto:craig@example.com\n"
+                  "DTSTART:" (test-calendar-sync-ics-datetime-local decl-start) "\n"
+                  "DTEND:" (test-calendar-sync-ics-datetime-local decl-end) "\n"
+                  "END:VEVENT\n"
+                  "END:VCALENDAR"))
+         (org-output (calendar-sync--parse-ics ics-content)))
+    (should (stringp org-output))
+    ;; The non-declined occurrences survive.
+    (should (string-match-p "1on1 with Hayk" org-output))
+    ;; The declined occurrence (unique marker) is dropped.
+    (should-not (string-match-p "DECLINEDWEEK" org-output))))
+
 (provide 'test-integration-calendar-sync-recurrence-exceptions)
 ;;; test-integration-calendar-sync-recurrence-exceptions.el ends here