caldav party crasher

[kesselb]

Summary

Calendar: nextcloud/calendar#8222

TODO

Checklist

• Code is properly formatted
• Sign-off message is added to all commits
• Tests (unit, integration, api and/or acceptance) are included
• Screenshots before/after for front-end changes
• Documentation (manuals or wiki) has been updated or is not required
• Backports requested where applicable (ex: critical bugfixes)
• Labels added where applicable (ex: bug/enhancement, 3. to review, feature component)
• Milestone added for target branch/version (ex: 32.x for stable32)

AI (if applicable)

• The content of this PR was partly or fully generated using AI

[kesselb]

This is matching the upstream: https://github.com/sabre-io/vobject/blob/2104a3ea37e248262617a8acbfe7648d8e2fd8bd/lib/ITip/Broker.php#L437

@SebastianKrupinski do you know why we don't unset RSVP here like for the existing events in the loop before?

[SebastianKrupinski]

Hey, Just saw this comment. According to the RFC

Parameter Name
RSVP
Purpose
To specify whether there is an expectation of a favor of a reply from the calendar user specified by the property value.

So I would say once we have a reply there is no need for the RSVP

[Copilot]

Pull request overview

Adds a Nextcloud-specific “party crasher” control for CalDAV iTIP REPLY handling, plus unit tests, to prevent/allow adding new attendees from replies based on an X-NC-PARTY-CRASHER flag.

Changes:

• Add custom processMessageReply() handling in TipBroker to optionally reject “party crasher” attendees and to generate missing recurring exceptions.
• Register X-NC-PARTY-CRASHER as a typed VObject property via VCalendar::$propertyMap.
• Add unit tests covering allow/disallow/default behavior for single and generated recurring instances.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 6 comments.

File	Description
apps/dav/lib/CalDAV/TipBroker.php	Implements REPLY processing with party-crasher gating and recurring-instance generation.
apps/dav/lib/AppInfo/Application.php	Registers X-NC-PARTY-CRASHER in Sabre VObject’s VCalendar property map at app boot.
apps/dav/tests/unit/CalDAV/TipBrokerTest.php	Adds coverage for party-crasher allow/deny/default scenarios (including generated recurrences).

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[Copilot]

partyCrasher() only checks properties that are instances of Sabre\VObject\Property\Boolean. If the event contains X-NC-PARTY-CRASHER:FALSE but it gets parsed as a generic/unknown property (e.g. if the property map wasn’t initialized before parsing), this method will fall back to true and still allow party crashers. To make this robust, consider also checking the property's string value (case-insensitive) whenever the property exists, not only when it’s a Boolean instance.

Suggested change

	}
	}
	$value = strtoupper(trim((string)$property->getValue()));
	if ($value === 'TRUE' || $value === '1' || $value === 'YES') {
	return true;
	}
	if ($value === 'FALSE' || $value === '0' || $value === 'NO') {
	return false;
	}

[ChristophWurst]

Quick review

In terms of naming we could go with invitation forwarding. That's what we will call it on the UI, and what other platforms (Outlook) call it.