[gnome-calendar/fix-shifting-events] manager: Fix bug where recurring events shift after being edited

[Ray Strode <halfline src gnome org>]

commit fed9e3a498acd346674b0a710af48739bbe1c3f0
Author: Ray Strode <rstrode redhat com>
Date:   Tue Oct 11 15:33:36 2022 -0400

    manager: Fix bug where recurring events shift after being edited
    
    Right now if a user edits say event 3 in a set of 5 events, the
    whole event set gets shifted over by 3. It's as if the middle
    event is treated as the new first event.
    
    This is because of a hack in the code to clear the recurrence
    id of the event, to get at the "main event", and edit the whole
    set. This hack still leaves the start time on the event, causing
    the main event to use a middle event start time.
    
    This commit queries for the main event from the middle event,
    and sets the middle event start time to match the main event,
    before doing an update.
    
    Closes https://gitlab.gnome.org/GNOME/gnome-calendar/-/issues/882

 src/core/gcal-manager.c | 38 ++++++++++++++++++++++++++++++++++++--
 1 file changed, 36 insertions(+), 2 deletions(-)
---
diff --git a/src/core/gcal-manager.c b/src/core/gcal-manager.c
index c5c54d36..b3920c25 100644
--- a/src/core/gcal-manager.c
+++ b/src/core/gcal-manager.c
@@ -1056,10 +1056,44 @@ gcal_manager_update_event (GcalManager           *self,
    * HACK: In Evolution Calendar, a NULL 'rid' is usually associated
    * with an E_CAL_OBJ_MOD_ALL modtype. Here, we are manually setting
    * the rid to NULL when modifying a recurrent event with MOD_ALL
-   * modtype.
+   * modtype. This gives us the associated main event. We also need
+   * to fudge the event date start and end times to match that event.
    */
   if (mod == GCAL_RECURRENCE_MOD_ALL)
-    e_cal_component_set_recurid (component, NULL);
+  {
+      GError *error = NULL;
+      ECalComponentId *component_id;
+      ICalComponent *icalcomponent;
+
+      component_id = e_cal_component_get_id (component);
+      if (e_cal_client_get_object_sync (gcal_calendar_get_client (calendar),
+                                        e_cal_component_id_get_uid (component_id),
+                                        NULL,
+                                        &icalcomponent,
+                                        NULL,
+                                        &error))
+        {
+          ECalComponent *ecomponent;
+          ecomponent = e_cal_component_new_from_icalcomponent (icalcomponent);
+
+          if (ecomponent)
+            {
+              GcalEvent *main_event;
+
+              main_event = gcal_event_new (calendar, ecomponent, &error);
+
+              gcal_event_set_date_start (event, gcal_event_get_date_start (main_event));
+              gcal_event_set_date_end (event, gcal_event_get_date_end (main_event));
+
+              g_object_unref (main_event);
+              g_object_unref (ecomponent);
+            }
+        }
+        e_cal_component_id_free (component_id);
+        g_object_unref (icalcomponent);
+
+        e_cal_component_set_recurid (component, NULL);
+    }
 
   /*
    * While we're updating the event, we don't want the component