[Bug]: iMIP emails don't take all EXDATEs into account when generating the email text

[miaulalala]

⚠️ This issue respects the following points: ⚠️

• This is a bug, not a question or a configuration/webserver/proxy issue.
• This issue is not already reported on Github OR Nextcloud Community Forum (I've searched it).
• Nextcloud Server is up to date. See Maintenance and Release Schedule for supported versions.
• I agree to follow Nextcloud's Code of Conduct.

Bug description

Example ics:

BEGIN:VEVENT
CREATED:20241015T144600Z
DTSTAMP:20241016T111344Z
LAST-MODIFIED:20241016T111344Z
SEQUENCE:5
UID:95e3bd55-e1fc-4e1a-b247-f2d3cb680c1f
DTSTART;TZID=Europe/Vienna:20241016T100000
DTEND;TZID=Europe/Vienna:20241016T110000
STATUS:CONFIRMED
ATTENDEE;CN=Anna Banana;CUTYPE=INDIVIDUAL;PARTSTAT=ACCEPTED;ROLE=REQ-PARTIC
 IPANT;LANGUAGE=en_GB;SCHEDULE-STATUS=1.1:mailto:adsdasdsa@gmx.net
ORGANIZER;CN=Bob:mailto:adssdassad@gmail.com
SUMMARY:Testing Weekly
RRULE:FREQ=WEEKLY;BYDAY=WE
EXDATE;TZID=Europe/Vienna:20241023T100000
EXDATE;TZID=Europe/Vienna:20241106T100000
EXDATE;TZID=Europe/Vienna:20241113T100000
BEGIN:VALARM
ACTION:DISPLAY
TRIGGER;RELATED=START:-PT10M
SUMMARY:Testing Weekly
DESCRIPTION:Dies ist eine Terminerinnerung.
ATTENDEE:mailto:adsadsadsa@gmx.net
END:VALARM
END:VEVENT

Steps to reproduce

Create an event with unlimited repetitions and cancel the 2nd, 4th and 5th in the series.

Expected behavior

The EXDATEs are taken into account and the string generated reflects that fact.

Nextcloud Server version

master

Operating system

Debian/Ubuntu

PHP engine version

PHP 8.2

Web server

Apache (supported)

Database engine version

MySQL

Is this bug present after an update or on a fresh install?

Upgraded to a MAJOR version (ex. 28 to 29)

Are you using the Nextcloud Server Encryption module?

None

What user-backends are you using?

• Default user-backend (database)
• LDAP/ Active Directory
• SSO - SAML
• Other

Configuration report

No response

List of activated Apps

No response

Nextcloud Signing status

No response

Nextcloud Logs

No response

Additional info

No response

[SebastianKrupinski]

Found the issue... RFC example states the EXDATE property should be "EXDATE:19960402T010000Z,19960403T010000Z,19960404T010000Z" but we use one instance of EXDATE property per date, "EXDATE:19960402T010000Z", "EXDATE:19960403T010000Z", etc.

I'll have it fixed today.