[Bug] Creating Talk room for event on shared calendar fails: CalDavEventListener uses calendar owner instead of acting user

## Steps to reproduce
1. User A shares a calendar with User B
2. User B opens the shared calendar in Nextcloud Calendar
3. User B creates a new event on the shared calendar, clicks "Create Talk room for this event" and **invites User A (the calendar owner) as attendee**
4. User B tries to save the event

### Expected behaviour
The event is saved successfully and the Talk room is linked to the calendar event, without any error message.

### Actual behaviour
The CalDAV PUT request returns `400 Bad Request`. An error message is displayed saying the event could not be saved, even though the event **is** actually saved. The Talk room integration is broken — the room is not properly linked to the event.

The server log shows:
```
{"reqId":"n5kspFT3unoc1XkpWAZ1","level":2,"time":"2026-05-27T12:05:40+00:00","remoteAddr":"2a0a:e805:617:34::","user":"admin","app":"spreed","method":"PUT","url":"/remote.php/dav/calendars/admin/edvk_shared_by_christianguggisberg/E002DA07-1DF4-46D5-B7C2-09A7D8302FC5.ics","scriptName":"/remote.php","message":"Room with hsb6xitr not found for calendar event integration","userAgent":"Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/148.0.0.0 Safari/537.36","version":"32.0.8.2","data":{"app":"spreed"}}
```

The browser console shows:
```
PUT https://cloud.example.com/remote.php/dav/calendars/[owner]/[calendar]/[event].ics 400 (Bad Request)
[ERROR] calendar: Failed to save event
```

**Root cause analysis:**
The bug is in `lib/Listener/CalDavEventListener.php` line 114. The listener extracts the `userId` from the calendar's `principaluri` (= calendar **owner**, User A), but uses it to look up the Talk room which was created by the **acting user** (User B, who is editing the shared calendar). Since the room was created by User B and not the calendar owner User A, `getRoomForUserByToken($roomToken, $calendarOwnerUserId)` throws a `RoomNotFoundException`.

The issue is specifically triggered when the calendar owner (User A) is invited as an attendee to the event. The event system (`CalendarObjectCreatedEvent`) does not expose the acting user, only the `principaluri` of the calendar — which in a shared calendar scenario is a different user than the one performing the action. A proper fix may require the event to carry an `actingUserId` field, potentially in `nextcloud/server`.

## Talk app
**Talk app version:** 22.0.12
**Custom Signaling server configured:** allinone
**Custom TURN server configured:** allinone
**Custom STUN server configured:** allinone

## Browser
**Microphone available:** yes
**Camera available:** yes
**Operating system:** Win 11
**Browser name:** Chrome
**Browser version:** 148.0.7778.179

### Browser log
<details>

```
calendarObjects.js:122  PUT https://cloud.ehv.ch/remote.php/dav/calendars/admin/edvk_shared_by_christianguggisberg/E002DA07-1DF4-46D5-B7C2-09A7D8302FC5.ics 400 (Bad Request)
(anonymous) @ xhr.js:210
(anonymous) @ xhr.js:12
aborted @ dispatchRequest.js:46
_request @ Axios.js:211
request @ Axios.js:39
(anonymous) @ bind.js:10
request @ index.mjs:821
put @ index.mjs:663
this @ index.mjs:1390
createVObject @ index.mjs:1981
updateCalendarObject @ calendarObjects.js:122
(anonymous) @ pinia.mjs:1396
saveCalendarObjectInstance @ calendarObjectInstance.js:1513
(anonymous) @ pinia.mjs:1396
save @ EditorMixin.js:634
saveAndLeave @ EditorMixin.js:658
saveAndView @ EditSimple.vue:809
EditorMixin.js:639 [ERROR] calendar: Failed to save event
```
</details>

## Server configuration
**Operating system:** allinone on Ubuntu
**Web server:** nginx
**Database:** pgsql
**PHP version:** 8.3.30
**Nextcloud Version:** 32.0.8

**List of activated apps:**
<details>

```
Enabled:
  - activity: 5.0.0
  - admin_audit: 1.22.0
  - announcementcenter: 7.4.0
  - bruteforcesettings: 5.0.0
  - calendar: 6.4.2
  - circles: 32.0.0
  - cloud_federation_api: 1.16.0
  - comments: 1.22.0
  - contacts: 8.3.12
  - contactsinteraction: 1.13.1
  - dashboard: 7.12.0
  - dav: 1.34.2
  - drawio: 4.1.4
  - external: 7.0.1
  - federatedfilesharing: 1.22.0
  - files: 2.4.0
  - files_antivirus: 6.2.0
  - files_downloadlimit: 5.0.0
  - files_external: 1.24.1
  - files_fulltextsearch: 32.0.2
  - files_pdfviewer: 5.0.0
  - files_reminders: 1.5.0
  - files_sharing: 1.24.1
  - files_trashbin: 1.22.0
  - files_versions: 1.25.0
  - forms: 5.2.8
  - fulltextsearch: 32.0.0
  - fulltextsearch_elasticsearch: 32.0.2
  - groupfolders: 20.1.13
  - impersonate: 3.0.1
  - logreader: 5.0.0
  - lookup_server_connector: 1.20.0
  - mail: 5.8.1
  - nextcloud-aio: 0.8.0
  - nextcloud_announcements: 4.0.0
  - notifications: 5.0.0
  - notify_push: 1.3.3
  - oauth2: 1.20.0
  - polls: 9.1.4
  - previewgenerator: 5.13.0
  - profile: 1.1.0
  - provisioning_api: 1.22.0
  - quota_warning: 1.23.0
  - related_resources: 3.0.0
  - richdocuments: 9.0.6
  - serverinfo: 4.0.0
  - settings: 1.15.1
  - sharebymail: 1.22.0
  - spreed: 22.0.12
  - support: 4.0.0
  - suspicious_login: 10.0.0
  - tasks: 0.17.1
  - terms_of_service: 4.6.1
  - theming: 2.7.0
  - theming_customcss: 1.20.0
  - twofactor_backupcodes: 1.21.0
  - updatenotification: 1.22.0
  - user_saml: 8.0.1
  - user_status: 1.12.0
  - viewer: 5.0.0
  - weather_status: 1.12.0
  - webhook_listeners: 1.3.0
  - welcome: 2.0.0
  - workflowengine: 2.14.0
Disabled:
  - app_api: 32.0.0 (installed 4.0.5)
  - encryption: 2.20.0
  - federation: 1.22.0 (installed 1.5.0)
  - firstrunwizard: 5.0.0 (installed 2.15.0)
  - password_policy: 4.0.0 (installed 1.18.0)
  - photos: 5.0.0 (installed 1.0.0)
  - privacy: 4.0.0 (installed 1.6.0)
  - recommendations: 5.0.0 (installed 0.4.0)
  - survey_client: 4.0.0 (installed 1.3.0)
  - systemtags: 1.22.0 (installed 1.5.0)
  - text: 6.0.1 (installed 2.0.0)
  - twofactor_nextcloud_notification: 6.0.0 (installed 3.8.0)
  - twofactor_totp: 14.0.0 (installed 10.0.0-beta.2)
  - user_ldap: 1.23.0 (installed 1.21.0)

```
</details>

**Nextcloud configuration:**
<details>

```
{
    "system": {
        "one-click-instance": true,
        "one-click-instance.user-limit": 100,
        "memcache.local": "\\OC\\Memcache\\APCu",
        "apps_paths": [
            {
                "path": "\/var\/www\/html\/apps",
                "url": "\/apps",
                "writable": false
            },
            {
                "path": "\/var\/www\/html\/custom_apps",
                "url": "\/custom_apps",
                "writable": true
            }
        ],
        "appsallowlist": false,
        "check_data_directory_permissions": false,
        "memcache.distributed": "\\OC\\Memcache\\Redis",
        "memcache.locking": "\\OC\\Memcache\\Redis",
        "redis": {
            "host": "***REMOVED SENSITIVE VALUE***",
            "password": "***REMOVED SENSITIVE VALUE***",
            "port": 6379
        },
        "overwritehost": "cloud.ehv.ch",
        "overwriteprotocol": "https",
        "passwordsalt": "***REMOVED SENSITIVE VALUE***",
        "secret": "***REMOVED SENSITIVE VALUE***",
        "trusted_domains": [
            "localhost",
            "cloud.ehv.ch"
        ],
        "datadirectory": "***REMOVED SENSITIVE VALUE***",
        "skeletondirectory": "",
        "dbtype": "pgsql",
        "version": "32.0.8.2",
        "overwrite.cli.url": "https:\/\/cloud.ehv.ch\/",
        "dbname": "***REMOVED SENSITIVE VALUE***",
        "dbhost": "***REMOVED SENSITIVE VALUE***",
        "dbport": "",
        "dbtableprefix": "oc_",
        "dbuser": "***REMOVED SENSITIVE VALUE***",
        "dbpassword": "***REMOVED SENSITIVE VALUE***",
        "installed": true,
        "instanceid": "***REMOVED SENSITIVE VALUE***",
        "maintenance": false,
        "updatedirectory": "\/nc-updater",
        "default_phone_region": "CH",
        "loglevel": 1,
        "log_type": "file",
        "logfile": "\/var\/www\/html\/data\/nextcloud.log",
        "log_rotate_size": "10485760",
        "log.condition": {
            "apps": [
                "admin_audit"
            ]
        },
        "preview_max_x": "2048",
        "preview_max_y": "2048",
        "jpeg_quality": "60",
        "maintenance_window_start": 100,
        "enabledPreviewProviders": {
            "1": "OC\\Preview\\Image",
            "2": "OC\\Preview\\MarkDown",
            "3": "OC\\Preview\\MP3",
            "4": "OC\\Preview\\TXT",
            "5": "OC\\Preview\\OpenDocument",
            "6": "OC\\Preview\\Movie",
            "7": "OC\\Preview\\Krita",
            "0": "OC\\Preview\\Imaginary",
            "23": "OC\\Preview\\ImaginaryPDF"
        },
        "enable_previews": true,
        "upgrade.disable-web": true,
        "mail_smtpmode": "smtp",
        "trashbin_retention_obligation": "auto, 30",
        "versions_retention_obligation": "auto, 30",
        "activity_expire_days": "30",
        "simpleSignUpLink.shown": false,
        "share_folder": "\/Shared",
        "one-click-instance.link": "https:\/\/nextcloud.com\/all-in-one\/",
        "upgrade.cli-upgrade-link": "https:\/\/github.com\/nextcloud\/all-in-one\/discussions\/2726",
        "allow_local_remote_servers": true,
        "davstorage.request_timeout": 3600,
        "htaccess.RewriteBase": "\/",
        "dbpersistent": false,
        "files_external_allow_create_new_local": false,
        "trusted_proxies": "***REMOVED SENSITIVE VALUE***",
        "preview_imaginary_url": "***REMOVED SENSITIVE VALUE***",
        "mail_sendmailmode": "smtp",
        "mail_from_address": "***REMOVED SENSITIVE VALUE***",
        "mail_domain": "***REMOVED SENSITIVE VALUE***",
        "mail_smtphost": "***REMOVED SENSITIVE VALUE***",
        "mail_smtpport": "465",
        "mail_smtpauth": true,
        "mail_smtpname": "***REMOVED SENSITIVE VALUE***",
        "mail_smtppassword": "***REMOVED SENSITIVE VALUE***",
        "mail_smtpsecure": "ssl",
        "preview_imaginary_key": "***REMOVED SENSITIVE VALUE***",
        "auth.bruteforce.protection.enabled": true,
        "ratelimit.protection.enabled": true,
        "documentation_url.server_logs": "https:\/\/github.com\/nextcloud\/all-in-one\/discussions\/5425",
        "forbidden_filename_characters": [
            "\\",
            "\/"
        ],
        "forbidden_filename_extensions": [
            ".filepart",
            ".part"
        ],
        "updatechecker": false,
        "DOMAIN": "cloud.ehv.ch",
        "AIO_VERSION": "v12.9.2"
    }
}

```
</details>

### Server log (data/nextcloud.log)
<details>

```
{"reqId":"n5kspFT3unoc1XkpWAZ1","level":2,"time":"2026-05-27T12:05:40+00:00","remoteAddr":"2a0a:e805:617:34::","user":"admin","app":"spreed","method":"PUT","url":"/remote.php/dav/calendars/admin/edvk_shared_by_christianguggisberg/E002DA07-1DF4-46D5-B7C2-09A7D8302FC5.ics","scriptName":"/remote.php","message":"Room with hsb6xitr not found for calendar event integration","userAgent":"Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/148.0.0.0 Safari/537.36","version":"32.0.8.2","data":{"app":"spreed"}}
```
</details>

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[Bug] Creating Talk room for event on shared calendar fails: CalDavEventListener uses calendar owner instead of acting user #18120

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[Bug] Creating Talk room for event on shared calendar fails: CalDavEventListener uses calendar owner instead of acting user #18120

Description

Steps to reproduce

Expected behaviour

Actual behaviour

Talk app

Browser

Browser log

Server configuration

Server log (data/nextcloud.log)

Metadata

Metadata

Assignees

Labels

Type

Fields

Projects

Milestone

Relationships

Development

Issue actions