Fix JMAP: CalendarEvent/get returns null for requested recurrenceRule and recurrenceOverrides properties on synthetic recurrence instances

CHANGELOG.md

@@ -31,6 +31,7 @@ If you are upgrading from v0.16.x, replace the binary (or run `docker pull`). If
 - JMAP:
   - `CalendarEvent/set` stores `useDefaultAlerts` per user, and `CalendarEvent/get` returns `false` when it was never set.
   - `CalendarEvent/get` returns `null` for `baseEventId` unless the id is a synthetic recurrence instance.
+  - `CalendarEvent/get` returns `null` for requested `recurrenceRule` and `recurrenceOverrides` properties on synthetic recurrence instances.
 
 ## [0.16.21] - 2026-09-06
 

crates/jmap/src/calendar_event/get.rs

@@ -517,10 +517,28 @@ impl CalendarEventGet for Server {
                 let mut result = if return_all_properties {
                     jscal.into_object().unwrap()
                 } else {
-                    Map::from_iter(jscal.into_expanded_object().filter(|(k, _)| {
-                        k.as_property()
-                            .is_some_and(|p| jscal_properties.contains(p))
-                    }))
+                    let is_synthetic = id.is_synthetic();
+                    let is_null_for_synthetic = |property: &JSCalendarProperty<Id>| {
+                        is_synthetic
+                            && matches!(
+                                property,
+                                JSCalendarProperty::RecurrenceRule
+                                    | JSCalendarProperty::RecurrenceOverrides
+                            )
+                    };
+                    let mut result =
+                        Map::from_iter(jscal.into_expanded_object().filter(|(k, _)| {
+                            k.as_property().is_some_and(|p| {
+                                jscal_properties.contains(p) && !is_null_for_synthetic(p)
+                            })
+                        }));
+                    for property in jscal_properties
+                        .iter()
+                        .filter(|property| is_null_for_synthetic(property))
+                    {
+                        result.insert_unchecked(property.clone(), Value::Null);
+                    }
+                    result
                 };
 
                 for property in &jmap_properties {

tests/src/jmap/calendar/instance.rs

@@ -105,6 +105,24 @@ pub async fn test(test: &TestServer) {
         "2007-03-07T12:00:00"
     );
 
+    // Synthetic instances return null recurrence properties when requested
+    for start in [
+        "2007-03-05T12:00:00",
+        "2007-03-06T12:00:00",
+        "2007-03-07T15:00:00",
+        "2007-03-08T12:00:00",
+        "2007-03-09T12:00:00",
+    ] {
+        let instance = instance(&instances, start);
+        for property in ["recurrenceRule", "recurrenceOverrides"] {
+            assert_eq!(
+                instance.get(property),
+                Some(&Value::Null),
+                "{property} on {start}: {instance:?}"
+            );
+        }
+    }
+
     // Unknown instances are reported as not found
     let unknown_id =
         Id::from_parts(1000, Id::from_str(&recurring_id).unwrap().document_id()).to_string();
@@ -912,6 +930,8 @@ async fn expand_instances(account: &Account, calendar_id: &str) -> Vec<Value> {
                 "title",
                 "recurrenceId",
                 "locations",
+                "recurrenceRule",
+                "recurrenceOverrides",
             ],
             ids,
         )