[Bug]: MKCALENDAR without supported-calendar-component-set doesn't support journals by default

[rfc2822]

⚠️ 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 sending a MKCALENDAR request without supported-calendar-component-set, Nextcloud creates a collection that reports to support VEVENT and VTODO, but not VJOURNAL.

However, it is possible to create a collection that supports all three component types, because it works when it's explicitly requested.

Steps to reproduce

1. Create calendar with MKCALENDAR (without supported-calendar-component-set).
2. Do PROPFIND on the new calendar and request supported-calendar-component-set.
3. supported-calendar-component-set contains only VEVENT and VTODO (but not VJOURNAL).

To verify that it's possible to create collections that contain VEVENT, VTODO and VJOURNAL:

1. Create another calendar with MKCALENDAR and specify supported-calendar-component-set = (VEVENT,VTODO,VJOURNAL).
2. Do PROPFIND on the new calendar and request supported-calendar-component-set.
3. supported-calendar-component-set contains VEVENT, VTODO and VJOURNAL.

Expected behavior

The CalDAV RFC says:

In the absence of this property [supported-calendar-component-set], the server MUST accept all component types, and the client can assume that all component types are accepted.

So collections that are created without supported-calendar-component-set should also support journals.

Installation method

Community Manual installation with Archive

Nextcloud Server version

28

Operating system

None

PHP engine version

None

Web server

None

Database engine version

None

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

None

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

{
    "system": {
        "instanceid": "***REMOVED SENSITIVE VALUE***",
        "passwordsalt": "***REMOVED SENSITIVE VALUE***",
        "secret": "***REMOVED SENSITIVE VALUE***",
        "trusted_domains": [
            "davtest.dev001.net"
        ],
        "datadirectory": "***REMOVED SENSITIVE VALUE***",
        "dbtype": "mysql",
        "version": "28.0.4.1",
        "overwrite.cli.url": "https:\/\/davtest.dev001.net\/nextcloud",
        "dbname": "***REMOVED SENSITIVE VALUE***",
        "dbhost": "***REMOVED SENSITIVE VALUE***",
        "dbport": "",
        "dbtableprefix": "oc_",
        "mysql.utf8mb4": true,
        "dbuser": "***REMOVED SENSITIVE VALUE***",
        "dbpassword": "***REMOVED SENSITIVE VALUE***",
        "installed": true,
        "memcache.local": "\\OC\\Memcache\\APCu",
        "loglevel": 0,
        "logdateformat": "F d, Y H:i:s",
        "log_rotate_size": 104857600,
        "maintenance": false,
        "theme": "",
        "debug": true,
        "updater.secret": "***REMOVED SENSITIVE VALUE***"
    }
}

List of activated Apps

Enabled:
  - activity: 2.20.0
  - calendar: 4.7.3
  - calendar_resource_management: 0.7.0
  - circles: 28.0.0
  - cloud_federation_api: 1.11.0
  - comments: 1.18.0
  - contacts: 5.5.3
  - contactsinteraction: 1.9.0
  - dashboard: 7.8.0
  - dav: 1.29.1
  - dav_push: 0.0.1
  - dav_push_notify_push_transport: 0.0.1
  - deck: 1.12.2
  - federatedfilesharing: 1.18.0
  - federation: 1.18.0
  - files: 2.0.0
  - files_pdfviewer: 2.9.0
  - files_reminders: 1.1.0
  - files_sharing: 1.20.0
  - files_trashbin: 1.18.0
  - files_versions: 1.21.0
  - firstrunwizard: 2.17.0
  - impersonate: 1.15.0
  - logreader: 2.13.0
  - lookup_server_connector: 1.16.0
  - nextcloud_announcements: 1.17.0
  - notes: 4.10.0
  - notifications: 2.16.0
  - oauth2: 1.16.3
  - password_policy: 1.18.0
  - photos: 2.4.0
  - privacy: 1.12.0
  - provisioning_api: 1.18.0
  - recommendations: 2.0.0
  - related_resources: 1.3.0
  - serverinfo: 1.18.0
  - settings: 1.10.1
  - sharebymail: 1.18.0
  - support: 1.11.1
  - survey_client: 1.16.0
  - systemtags: 1.18.0
  - tasks: 0.16.0
  - text: 3.9.1
  - theming: 2.3.0
  - twofactor_backupcodes: 1.17.0
  - updatenotification: 1.18.0
  - user_status: 1.8.1
  - viewer: 2.2.0
  - weather_status: 1.8.0
  - workflowengine: 2.10.0
Disabled:
  - admin_audit: 1.18.0
  - bruteforcesettings: 2.8.0
  - encryption: 2.16.0
  - files_external: 1.20.0
  - files_markdown: 2.4.1 (installed 2.4.1)
  - files_rightclick: 0.15.1 (installed 1.6.0)
  - pushdemo: 0.0.1 (installed 0.0.1)
  - suspicious_login: 6.0.0
  - twofactor_totp: 10.0.0-beta.2
  - user_ldap: 1.19.0

Nextcloud Signing status

No response

Nextcloud Logs

No response

Additional info

No response

[kesselb]

Thank you 👍

server/apps/dav/lib/CalDAV/CalDavBackend.php

Line 757 in b769dc4

'components' => 'VEVENT,VTODO',

Sabre also uses "VEVENT,VTODO" as default: https://github.com/sabre-io/dav/blame/7a736b73bea7040a7b6535fd92ff6de9981e5190/lib/CalDAV/Backend/PDO.php#L242

I don't know if that means something would be missing to support it properly, or just an oversight.

cc @miaulalala @st3iny

[joshtrichards]

Related: nextcloud/calendar#4436

[st3iny]

I think it is just an oversight and our backend should be able to handle VJOURNALs just fine. It is probably not included in our code because there is no "official" frontend to render VJOURNALs.