Document fails to load on public share. Throws null userId/groupID error

[whisperdancer]

Nextcloud 23.0.2
Nextcloud Office 5.0.3
Collabora/code docker COOLWSD v21.11.2.4

Testing public share link on a collabora office doc. When I open the link as the share recipient on separate browser it prompts to enter a name and then fails to load. The nextcloud log shows the error:

Caused by TypeError: OC\Group\Manager::getUserIdGroupIds(): Argument #1 ($uid) must be of type string, null given, called in /var/www/nextcloud/lib/private/Group/Manager.php on line 316

To reproduce:

1. Create public share on a collabora office document, spreadsheet, etc
2. Check "allow edit" permission
3. Copy link
4. On separate browser in private mode, paste link
5. It opens and prompts to enter name
6. Doc fails to load

Full error from nextcloud log:

Exception: OC\Group\Manager::getUserIdGroupIds(): Argument #1 ($uid) must be of type string, null given, called in /var/www/nextcloud/lib/private/Group/Manager.php on line 316 in file '/var/www/nextcloud/lib/private/Group/Manager.php' line 333

    /var/www/nextcloud/lib/private/AppFramework/App.php - line 157:
    OC\AppFramework\Http\Dispatcher->dispatch()
    /var/www/nextcloud/lib/private/Route/Router.php - line 302:
    OC\AppFramework\App::main()
    /var/www/nextcloud/lib/base.php - line 1006:
    OC\Route\Router->match()
    /var/www/nextcloud/index.php - line 36:
    OC::handleRequest()

Caused by TypeError: OC\Group\Manager::getUserIdGroupIds(): Argument #1 ($uid) must be of type string, null given, called in /var/www/nextcloud/lib/private/Group/Manager.php on line 316
    /var/www/nextcloud/lib/private/Group/Manager.php - line 316:
    OC\Group\Manager->getUserIdGroupIds()
    /var/www/nextcloud/apps/richdocuments/lib/Controller/WopiController.php - line 334:
    OC\Group\Manager->isInGroup()
    /var/www/nextcloud/apps/richdocuments/lib/Controller/WopiController.php - line 223:
    OCA\Richdocuments\Controller\WopiController->shouldWatermark()
    /var/www/nextcloud/lib/private/AppFramework/Http/Dispatcher.php - line 217:
    OCA\Richdocuments\Controller\WopiController->checkFileInfo()
    /var/www/nextcloud/lib/private/AppFramework/Http/Dispatcher.php - line 126:
    OC\AppFramework\Http\Dispatcher->executeController()
    /var/www/nextcloud/lib/private/AppFramework/App.php - line 157:
    OC\AppFramework\Http\Dispatcher->dispatch()
    /var/www/nextcloud/lib/private/Route/Router.php - line 302:
    OC\AppFramework\App::main()
    /var/www/nextcloud/lib/base.php - line 1006:
    OC\Route\Router->match()
    /var/www/nextcloud/index.php - line 36:
    OC::handleRequest()

[juliusknorr]

This was fixed with #2470