Accepting MS Office invitations breaks web calendar

[G0ldmember]

Steps to reproduce

1. create meeting invitation in Office365
2. Accept it in external client (e.g. Thunderbird) and add it to Owncloud calendar
3. Navigate to web calendar within owncloud and see... nothing

Expected behaviour

Web calendar should display and show the new event

Actual behaviour

Web calendar loads but as soon as the "critical" event is within the selected time frame which is currently viewed in the caledar, the entire calendar does not show. Other calendars are shown as usual. Firebug reports that the requests to retrieve the Caldav data are sent and properly answered, the answer do include the Caldav information, but obviously there is a problem when the calendar data is rendered and it breaks somewhere.

Server configuration

Operating system: Debian Stretch

Web server: Apache 2.4

Database:

PHP version: 7.0.30

ownCloud version: 10.0.91+1.1

Calendar version: 1.5.7

Updated from an older installed version or fresh install: Updated

List of activated apps:

Enabled:
  - activity: 2.3.6
  - admin_dependencies_chk: 0.02
  - bookmarks: 0.10.2
  - calendar: 1.5.7
  - comments: 0.3.0
  - configreport: 0.1.1
  - contacts: 1.5.3
  - dav: 0.3.2
  - federatedfilesharing: 0.3.1
  - federation: 0.1.0
  - files: 1.5.1
  - files_external: 0.7.1
  - files_pdfviewer: 0.8.2
  - files_sharing: 0.10.1
  - files_texteditor: 2.2.1
  - files_trashbin: 0.9.1
  - files_versions: 1.3.0
  - files_videoplayer: 0.9.8
  - firstrunwizard: 1.1
  - gallery: 16.0.2
  - market: 0.2.4
  - notifications: 0.3.4
  - richdocuments: 2.0.5
  - systemtags: 0.3.0
  - tasks: 0.9.6
  - updatenotification: 0.2.1
  - user_ldap: 0.10.0

ownCloud configuration:

{
    "system": {
        "instanceid": "oc46ab6f3046",
        "passwordsalt": "***REMOVED SENSITIVE VALUE***",
        "trusted_domains": [
            "cloud.wikon.de"
        ],
        "datadirectory": "\/data\/owncloud\/",
        "dbtype": "pgsql",
        "version": "10.0.9.5",
        "dbname": "owncloud",
        "dbhost": "127.0.0.1",
        "dbtableprefix": "oc_",
        "dbuser": "***REMOVED SENSITIVE VALUE***",
        "proxy": "proxy.wikon.de:3128",
        "dbpassword": "***REMOVED SENSITIVE VALUE***",
        "installed": true,
        "ldapIgnoreNamingRules": false,
        "overwritewebroot": "\/owncloud",
        "overwrite.cli.url": "\/owncloud",
        "loglevel": "2",
        "logtimezone": "Europe\/Berlin",
        "forcessl": true,
        "theme": "wikon",
        "maintenance": false,
        "secret": "***REMOVED SENSITIVE VALUE***",
        "mail_from_address": "***REMOVED SENSITIVE VALUE***",
        "mail_smtpmode": "php",
        "mail_domain": "***REMOVED SENSITIVE VALUE***",
        "memcache.local": "\\OC\\Memcache\\APCu",
        "trashbin_retention_obligation": "auto",
        "updatechecker": false,
        "appstore.experimental.enabled": true
    }
}

Are you using encryption: no

Client configuration

Browser: Firefox 62.0

Operating system: Ubuntu 16.04.5 LTS

CalDAV-clients: Thunderbird, Webcal

Logs

Web server error log

none

Log file (data/owncloud.log)

none

Browser log (Request)

<c:calendar-query xmlns:c="urn:ietf:params:xml:ns:caldav"><d:prop xmlns:d="DAV:"><d:getetag/><c:calendar-data/></d:prop><c:filter><c:comp-filter name="VCALENDAR"><c:comp-filter name="VEVENT"><c:time-range start="20180918T220000Z" end="20180919T220000Z"/></c:comp-filter></c:comp-filter></c:filter></c:calendar-query>

The Event has one custom header field with an error:

X-LIC-ERROR;X-LIC-ERRORTYPE=PROPERTY-PARSE-ERROR:Parse error in property
  name: ACKNOWLEDGED

Firefox does not show any error, Chromium reports an error in app.js:4444 which is

app.js:4444 Uncaught (in promise) TypeError: Cannot read property 'hasProperty' of undefined
    at app.js:4444

So somehow, vevent object must be "undefined" here.

The corresponding line is:

if (!vevent.hasProperty('dtstart')) {

Caldav data received:

VERSION:2.0
PRODID:-//Apple Inc.//Mac OS X 10.13.6//EN
CALSCALE:GREGORIAN
BEGIN:VEVENT
TRANSP:TRANSPARENT
DTEND;VALUE=DATE:20180613
LAST-MODIFIED:20180806T114723Z
UID:efd3819e-8b51-45c3-9b87-9e641ecf69b0
EXDATE;VALUE=DATE:20180807
DTSTAMP:20180903T071414Z
X-MOZ-GENERATION:1
SEQUENCE:1
SUMMARY:BBS ll ARE
DTSTART;VALUE=DATE:20180612
X-APPLE-TRAVEL-ADVISORY-BEHAVIOR:AUTOMATIC
CREATED:20180530T093323Z
RRULE:FREQ=WEEKLY;INTERVAL=2
BEGIN:VALARM
X-WR-ALARMUID:B0E0ECF3-E6A5-4280-BB3D-E66267C6940D
UID:B0E0ECF3-E6A5-4280-BB3D-E66267C6940D
TRIGGER:-PT15H
ATTACH;VALUE=URI:Basso
ACTION:AUDIO
X-LIC-ERROR;X-LIC-ERRORTYPE=PROPERTY-PARSE-ERROR:Parse error in property
  name: ACKNOWLEDGED
X-APPLE-DEFAULT-ALARM:TRUE
ACKNOWLEDGED:20180903T071414Z
END:VALARM
END:VEVENT
END:VCALENDAR
</cal:calendar-data></d:prop><d:status>HTTP/1.1 200 OK</d:status></d:propstat></d:response><d:response><d:href>/owncloud/remote.php/[***REMOVED***].ics</d:href><d:propstat><d:prop><d:getetag>&quot;19b1409565b72af0142d80864536b59d&quot;</d:getetag><cal:calendar-data>BEGIN:VCALENDAR
PRODID:-//Mozilla.org/NONSGML Mozilla Calendar V1.1//EN
VERSION:2.0
BEGIN:VTIMEZONE
TZID:America/New_York
BEGIN:DAYLIGHT
TZOFFSETFROM:-0500
TZOFFSETTO:-0400
TZNAME:EDT
DTSTART:19700308T020000
RRULE:FREQ=YEARLY;BYDAY=2SU;BYMONTH=3
END:DAYLIGHT
BEGIN:STANDARD
TZOFFSETFROM:-0400
TZOFFSETTO:-0500
TZNAME:EST
DTSTART:19701101T020000
RRULE:FREQ=YEARLY;BYDAY=1SU;BYMONTH=11
END:STANDARD
END:VTIMEZONE
BEGIN:VEVENT
LAST-MODIFIED:20180913T052619Z
DTSTAMP:20180913T052619Z
UID:040000008200E00074C5B7101A82E00800000000C06CAC79964AD40100000000000000
 00100000006AF246724652A14A823578052CA8B6A0
SUMMARY:Integration Team Status Meeting
PRIORITY:5
STATUS:CONFIRMED
RECURRENCE-ID;TZID=America/New_York:20180919T100000
ORGANIZER;CN=[***REMOVED***];SCHEDULE-AGENT=CLIENT:mailto:[***REMOVED***]
ATTENDEE;RSVP=TRUE;[***REMOVED***]
DTSTART;TZID=America/New_York:20180919T100000
DTEND;TZID=America/New_York:20180919T110000
DESCRIPTION;LANGUAGE=en-US:[***REMOVED***]\n\n
CLASS:PUBLIC
TRANSP:OPAQUE
SEQUENCE:4
LOCATION;LANGUAGE=en-US:[***REMOVED***]
X-MICROSOFT-CDO-APPT-SEQUENCE:4
X-MICROSOFT-CDO-OWNERAPPTID:[***REMOVED***]
X-MICROSOFT-CDO-BUSYSTATUS:TENTATIVE
X-MICROSOFT-CDO-INTENDEDSTATUS:BUSY
X-MICROSOFT-CDO-ALLDAYEVENT:FALSE
X-MICROSOFT-CDO-IMPORTANCE:1
X-MICROSOFT-CDO-INSTTYPE:3
X-MICROSOFT-DONOTFORWARDMEETING:FALSE
X-MICROSOFT-DISALLOW-COUNTER:FALSE
X-MICROSOFT-LOCATIONS:[{&quot;DisplayName&quot;:&quot;[***REMOVED***]&quot;\,&quot;[***REMOVED***]
 FullAddress&quot;:&quot;&quot;}]
X-MOZ-RECEIVED-SEQUENCE:4
X-MOZ-RECEIVED-DTSTAMP:20180912T181626Z
END:VEVENT
END:VCALENDAR
</cal:calendar-data></d:prop><d:status>HTTP/1.1 200 OK</d:status></d:propstat></d:response><d:response><d:href>/owncloud/remote.php/dav/calendars/[***REMOVED***].ics</d:href><d:propstat><d:prop><d:getetag>&quot;[***REMOVED***]&quot;</d:getetag><cal:calendar-data>BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//Sabre//Sabre VObject 4.1.6//EN
BEGIN:VEVENT
UID:5b97c411043be
CATEGORIES:Urlaub
CLASS:PUBLIC
SUMMARY:Urlaub csc
DESCRIPTION:Urlaub csc
DTSTART;VALUE=DATE:20180919
DTEND;VALUE=DATE:20180922
DTSTAMP:20180911T153305Z
END:VEVENT
END:VCALENDAR
</cal:calendar-data></d:prop><d:status>HTTP/1.1 200 OK</d:status></d:propstat></d:response><d:response><d:href>/owncloud/remote.php/dav/calendars/[***REMOVED***].ics</d:href><d:propstat><d:prop><d:getetag>&quot;[***REMOVED***]&quot;</d:getetag><cal:calendar-data>BEGIN:VCALENDAR

[DeepDiver1975]

This issue is within the used ICAL library. Needs a deeper look ...