Fix calendar rrule until where event is fullday but rrule until has a non-0 time

CHANGELOG.md

@@ -23,6 +23,10 @@ planned for 2025-07-01
 - [workflow] Run linter und spellcheck with LTS node version (#3767)
 - [workflow] Split "Run test" step into two steps for more clarity (#3767)
 
+### Fixed
+
+- [calendar] fix fullday event rrule until with timezone offset (#3781)
+
 ### Updated
 
 - [core] Update dependencies

modules/default/calendar/calendarfetcherutils.js

@@ -293,6 +293,13 @@ const CalendarFetcherUtils = {
 
 					event.start = rule.options.dtstart;
 
+					// if until is set, and its a full day event, force the time to midnight. rrule gets confused with non-00 offset
+					// looks like MS Outlook sets the until time incorrectly for fullday events
+					if ((rule.options.until !== undefined) && CalendarFetcherUtils.isFullDayEvent(event)) {
+						Log.debug("fixup rrule until");
+						rule.options.until = new Date(new Date(moment(rule.options.until).startOf("day").add(1, "day")).getTime());
+					}
+
 					Log.debug("fix rrule start=", rule.options.dtstart);
 					Log.debug("event before rrule.between=", JSON.stringify(event, null, 2), "exdates=", event.exdate);
 					// fixup the exdate and recurrence date to local time too for post between() handling

tests/configs/modules/calendar/fullday_until.js

@@ -0,0 +1,27 @@
+let config = {
+	address: "0.0.0.0",
+	ipWhitelist: [],
+	timeFormat: 12,
+
+	modules: [
+		{
+			module: "calendar",
+			position: "bottom_bar",
+			config: {
+				hideDuplicates: false,
+				maximumEntries: 100,
+				calendars: [
+					{
+						maximumEntries: 100,
+						url: "http://localhost:8080/tests/mocks/fullday_until.ics"
+					}
+				]
+			}
+		}
+	]
+};
+
+/*************** DO NOT EDIT THE LINE BELOW ***************/
+if (typeof module !== "undefined") {
+	module.exports = config;
+}

tests/electron/modules/calendar_spec.js

@@ -84,6 +84,10 @@ describe("Calendar module", () => {
 			await helpers.startApplication("tests/configs/modules/calendar/rrule_until.js", "07 Mar 2024 10:38:00 GMT-07:00", [], "America/Los_Angeles");
 			await expect(doTestCount()).resolves.toBe(1);
 		});
+		it("Issue #3781 recurrence rrule until with date only uses timezone offset incorrectly", async () => {
+			await helpers.startApplication("tests/configs/modules/calendar/fullday_until.js", "01 May 2025", [], "America/Los_Angeles");
+			await expect(doTestCount()).resolves.toBe(1);
+		});
 	});
 
 	/*

tests/mocks/fullday_until.ics

@@ -0,0 +1,28 @@
+BEGIN:VCALENDAR
+BEGIN:VEVENT
+DESCRIPTION:\n
+RRULE:FREQ=YEARLY;UNTIL=20250504T230000Z;INTERVAL=1;BYMONTHDAY=5;BYMONTH=5
+UID:040000008200E00074C5B7101A82E00800000000DAEF6ED30D9FDA01000000000000000
+ 010000000D37F812F0777844A93E97B96AD2D278B
+SUMMARY:Person A's Birthday
+DTSTART;VALUE=DATE:20250505
+DTEND;VALUE=DATE:20250506
+CLASS:PUBLIC
+PRIORITY:5
+DTSTAMP:20250428T133000Z
+TRANSP:TRANSPARENT
+STATUS:CONFIRMED
+SEQUENCE:0
+LOCATION:
+X-MICROSOFT-CDO-APPT-SEQUENCE:0
+X-MICROSOFT-CDO-BUSYSTATUS:FREE
+X-MICROSOFT-CDO-INTENDEDSTATUS:BUSY
+X-MICROSOFT-CDO-ALLDAYEVENT:TRUE
+X-MICROSOFT-CDO-IMPORTANCE:1
+X-MICROSOFT-CDO-INSTTYPE:1
+X-MICROSOFT-DONOTFORWARDMEETING:FALSE
+X-MICROSOFT-DISALLOW-COUNTER:FALSE
+X-MICROSOFT-REQUESTEDATTENDANCEMODE:DEFAULT
+X-MICROSOFT-ISRESPONSEREQUESTED:FALSE
+END:VEVENT
+END:VCALENDAR