[Bug]: IMip plugin sends CANCELLED email for rooms / resources

[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

When cancelling an event that has a room / resource with a valid email address, the iMIP Plugin sends a CANCELLED email to the rooms / resources ATTENDEE

Steps to reproduce

1. Create event with a room / resource that has a valid email
2. Cancel the event
3. Check your email and see there's a mail for the cancelled event that is sent to the room / resource

Expected behavior

No email should be sent to the room / resource.

Installation method

Community Web installer on a VPS or web space

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?

Updated from a MINOR version (ex. 22.1 to 22.2)

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

[miaulalala]

The room is missing a CUTYPE when sending a CANCEL. I haven't found yet where that happens. I think it might be in the Broker. Investigating further.

Culprit is \Sabre\VObject\ITip\Broker::parseEvent -> \Sabre\VObject\ITip\Broker::parseEventForOrganizer (somewhere in the code the CUTYPE gets lost).

The issue is here: https://github.com/sabre-io/vobject/blob/caa7af8e3304c85c63cdb6464ecafe09bb9918f6/lib/ITip/Broker.php#L526-L528

The attendee that gets passed to a cancel has no other information than it's href.

Replacing it with

				$event->add(clone $calendar->VEVENT->ATTENDEE);

would to the trick, but the Broker can't be extended as it's intialised with new at the relevant code junctions.

Upstream PR needed.

[miaulalala]

in upstream: add getter for Broker