From c06fb4b9cd846210e71d71fa07b5279fa406cad8 Mon Sep 17 00:00:00 2001
From: Paul Woolcock <11843015+phw198@users.noreply.github.com>
Date: Sun, 1 Nov 2020 17:11:58 +0000
Subject: [PATCH] Handle null being returned from
 GetCalendarEntriesInRecurrence() #1082

---
 .../GoogleOgcs/GoogleCalendar.cs              |  4 +-
 src/OutlookGoogleCalendarSync/Recurrence.cs   | 72 ++++++++++---------
 2 files changed, 39 insertions(+), 37 deletions(-)

diff --git a/src/OutlookGoogleCalendarSync/GoogleOgcs/GoogleCalendar.cs b/src/OutlookGoogleCalendarSync/GoogleOgcs/GoogleCalendar.cs
index 86b15f29..b1cdc28e 100644
--- a/src/OutlookGoogleCalendarSync/GoogleOgcs/GoogleCalendar.cs
+++ b/src/OutlookGoogleCalendarSync/GoogleOgcs/GoogleCalendar.cs
@@ -186,8 +186,8 @@ public List<Event> GetCalendarEntriesInRecurrence(String recurringEventId) {
                 return result;
 
             } catch (System.Exception ex) {
-                Forms.Main.Instance.Console.Update("Failed to retrieve recurring events", Console.Markup.error);
-                log.Error(ex.Message);
+                Forms.Main.Instance.Console.UpdateWithError("Failed to retrieve recurring events", OGCSexception.LogAsFail(ex));
+                OGCSexception.Analyse(ex);
                 return null;
             }
         }
diff --git a/src/OutlookGoogleCalendarSync/Recurrence.cs b/src/OutlookGoogleCalendarSync/Recurrence.cs
index 2f9c403a..7ed9086a 100644
--- a/src/OutlookGoogleCalendarSync/Recurrence.cs
+++ b/src/OutlookGoogleCalendarSync/Recurrence.cs
@@ -438,6 +438,8 @@ private Event getGoogleInstance(ref Microsoft.Office.Interop.Outlook.Exception o
                 log.Debug("Google exception event is not cached. Retrieving all recurring instances...");
             }
             List<Event> gInstances = GoogleOgcs.Calendar.Instance.GetCalendarEntriesInRecurrence(gRecurringEventID);
+            if (gInstances == null) return null;
+
             //Add any new exceptions to local cache
             googleExceptions = googleExceptions.Union(gInstances.Where(ev => !String.IsNullOrEmpty(ev.RecurringEventId))).ToList();
             foreach (Event gInst in gInstances) {
@@ -524,47 +526,47 @@ public static void CreateGoogleExceptions(AppointmentItem ai, String recurringEv
 
             log.Debug("Creating Google recurrence exceptions.");
             List<Event> gRecurrences = GoogleOgcs.Calendar.Instance.GetCalendarEntriesInRecurrence(recurringEventId);
-            if (gRecurrences != null) {
-                RecurrencePattern rp = null;
-                Exceptions excps = null;
-                try {
-                    rp = ai.GetRecurrencePattern();
-                    excps = rp.Exceptions;
-                    for (int e = 1; e <= excps.Count; e++) {
-                        Microsoft.Office.Interop.Outlook.Exception oExcp = null;
-                        try {
-                            oExcp = excps[e];
-                            for (int g = 0; g < gRecurrences.Count; g++) {
-                                Event ev = gRecurrences[g];
-                                DateTime gDate = ev.OriginalStartTime.DateTime ?? DateTime.Parse(ev.OriginalStartTime.Date);
-                                Boolean isDeleted = exceptionIsDeleted(oExcp);
-                                if (isDeleted && !ai.AllDayEvent) { //Deleted items get truncated?!
-                                    gDate = gDate.Date;
-                                }
-                                if (oExcp.OriginalDate == gDate) {
-                                    if (isDeleted) {
-                                        Forms.Main.Instance.Console.Update(GoogleOgcs.Calendar.GetEventSummary(ev), Console.Markup.calendar);
-                                        Forms.Main.Instance.Console.Update("Recurrence deleted.");
-                                        ev.Status = "cancelled";
-                                        GoogleOgcs.Calendar.Instance.UpdateCalendarEntry_save(ref ev);
-                                    } else {
-                                        int exceptionItemsModified = 0;
-                                        Event modifiedEv = GoogleOgcs.Calendar.Instance.UpdateCalendarEntry(oExcp.AppointmentItem, ev, ref exceptionItemsModified, forceCompare: true);
-                                        if (exceptionItemsModified > 0) {
-                                            GoogleOgcs.Calendar.Instance.UpdateCalendarEntry_save(ref modifiedEv);
-                                        }
+            if (gRecurrences == null) return;
+
+            RecurrencePattern rp = null;
+            Exceptions excps = null;
+            try {
+                rp = ai.GetRecurrencePattern();
+                excps = rp.Exceptions;
+                for (int e = 1; e <= excps.Count; e++) {
+                    Microsoft.Office.Interop.Outlook.Exception oExcp = null;
+                    try {
+                        oExcp = excps[e];
+                        for (int g = 0; g < gRecurrences.Count; g++) {
+                            Event ev = gRecurrences[g];
+                            DateTime gDate = ev.OriginalStartTime.DateTime ?? DateTime.Parse(ev.OriginalStartTime.Date);
+                            Boolean isDeleted = exceptionIsDeleted(oExcp);
+                            if (isDeleted && !ai.AllDayEvent) { //Deleted items get truncated?!
+                                gDate = gDate.Date;
+                            }
+                            if (oExcp.OriginalDate == gDate) {
+                                if (isDeleted) {
+                                    Forms.Main.Instance.Console.Update(GoogleOgcs.Calendar.GetEventSummary(ev), Console.Markup.calendar);
+                                    Forms.Main.Instance.Console.Update("Recurrence deleted.");
+                                    ev.Status = "cancelled";
+                                    GoogleOgcs.Calendar.Instance.UpdateCalendarEntry_save(ref ev);
+                                } else {
+                                    int exceptionItemsModified = 0;
+                                    Event modifiedEv = GoogleOgcs.Calendar.Instance.UpdateCalendarEntry(oExcp.AppointmentItem, ev, ref exceptionItemsModified, forceCompare: true);
+                                    if (exceptionItemsModified > 0) {
+                                        GoogleOgcs.Calendar.Instance.UpdateCalendarEntry_save(ref modifiedEv);
                                     }
-                                    break;
                                 }
+                                break;
                             }
-                        } finally {
-                            oExcp = (Microsoft.Office.Interop.Outlook.Exception)OutlookOgcs.Calendar.ReleaseObject(oExcp);
                         }
+                    } finally {
+                        oExcp = (Microsoft.Office.Interop.Outlook.Exception)OutlookOgcs.Calendar.ReleaseObject(oExcp);
                     }
-                } finally {
-                    excps = (Exceptions)OutlookOgcs.Calendar.ReleaseObject(excps);
-                    rp = (RecurrencePattern)OutlookOgcs.Calendar.ReleaseObject(rp);
                 }
+            } finally {
+                excps = (Exceptions)OutlookOgcs.Calendar.ReleaseObject(excps);
+                rp = (RecurrencePattern)OutlookOgcs.Calendar.ReleaseObject(rp);
             }
         }