oxcical: check BY_SETPOS according to RFC 5545

lib/mapi/oxcical.cpp

@@ -482,8 +482,9 @@ static bool oxcical_parse_rrule(const ical_component &tzcom,
  tmp_int = 5;
  apr->recur_pat.pts.monthnth.recurnum = tmp_int;
  } else {
- if (irrule.check_bymask(RRULE_BY_DAY) ||
- irrule.check_bymask(RRULE_BY_SETPOS))
+ /* Cf. RFC 5545 pg. 43, "rule: BY_SETPOS" */
+ if (irrule.check_bymask(RRULE_BY_DAY) &&
+ !irrule.check_bymask(RRULE_BY_SETPOS))
  return false;
  int tmp_int;
  patterntype = PATTERNTYPE_MONTH;

tests/gxl-475.ics

@@ -0,0 +1,53 @@
+BEGIN:VCALENDAR
+METHOD:REQUEST
+PRODID:Microsoft Exchange Server 2010
+VERSION:2.0
+BEGIN:VTIMEZONE
+TZID:W. Europe Standard Time
+BEGIN:STANDARD
+DTSTART:16010101T030000
+TZOFFSETFROM:+0200
+TZOFFSETTO:+0100
+RRULE:FREQ=YEARLY;INTERVAL=1;BYDAY=-1SU;BYMONTH=10
+END:STANDARD
+BEGIN:DAYLIGHT
+DTSTART:16010101T020000
+TZOFFSETFROM:+0100
+TZOFFSETTO:+0200
+RRULE:FREQ=YEARLY;INTERVAL=1;BYDAY=-1SU;BYMONTH=3
+END:DAYLIGHT
+END:VTIMEZONE
+BEGIN:VEVENT
+ORGANIZER:MAILTO:organizer@localhost
+ATTENDEE;ROLE=REQ-PARTICIPANT;PARTSTAT=NEEDS-ACTION;RSVP=TRUE:MAILTO:pexip_
+ meeting_service@localhost
+DESCRIPTION;LANGUAGE=de-DE:Liebe Kolleginnen und Kollegen\,\n\nanbei finden
+RRULE:FREQ=MONTHLY;COUNT=6;INTERVAL=1;BYDAY=2MO
+UID:040000008200E00074C5B7101A82E0080000000000628DD5412CDA01000000000000000
+ 010000000364A1A3FF3EE024AAF97479096254D81
+SUMMARY;LANGUAGE=de-DE:AK FNH JF
+DTSTART;TZID=W. Europe Standard Time:20240108T130000
+DTEND;TZID=W. Europe Standard Time:20240108T150000
+CLASS:PUBLIC
+PRIORITY:5
+DTSTAMP:20231211T135716Z
+TRANSP:OPAQUE
+STATUS:CONFIRMED
+SEQUENCE:0
+LOCATION;LANGUAGE=de-DE:Meeting Service
+X-MICROSOFT-CDO-APPT-SEQUENCE:0
+X-MICROSOFT-CDO-OWNERAPPTID:1613481959
+X-MICROSOFT-CDO-BUSYSTATUS:TENTATIVE
+X-MICROSOFT-CDO-INTENDEDSTATUS:BUSY
+X-MICROSOFT-CDO-ALLDAYEVENT:FALSE
+X-MICROSOFT-CDO-IMPORTANCE:1
+X-MICROSOFT-CDO-INSTTYPE:1
+X-MICROSOFT-DONOTFORWARDMEETING:FALSE
+X-MICROSOFT-DISALLOW-COUNTER:FALSE
+BEGIN:VALARM
+DESCRIPTION:REMINDER
+TRIGGER;RELATED=START:-PT15M
+ACTION:DISPLAY
+END:VALARM
+END:VEVENT
+END:VCALENDAR