sharing shared files to deck can result in invisible stuff...

So, very strange:

0. User 0 shared a file to user 1
1. user 1 shared the file to conversation in Talk.
2. user 2 (who is in the Talk conversation and thus go the file) shared the file to a deck card
3. user 3 goes to deck, sees the 'attachment' icon but finds no attachment

now previously, I went through these steps, then revoked the share to the conversation and removed it from the deck card. This might have caused something... odd in the server. The logs are now having loads of these:

{"reqId":"5dorBQn3PZv6SKNPVC9P","level":3,"time":"2021-09-02T16:37:48+00:00","remoteAddr":"91.66.7.139","user":"leon","app":"deck","method":"GET","url":"/apps/deck/cards/37/attachments","message":"Node for share not found, fileid: 2294","userAgent":"Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Firefox/91.0","version":"22.1.1.2","exception":{"Exception":"OCP\\Files\\NotFoundException","Message":"Node for share not found, fileid: 2294","Code":0,"Trace":[{"file":"/var/www/tech-preview.nextcloud.com/apps/deck/lib/Service/FilesAppService.php","line":83,"function":"getNode","class":"OC\\Share20\\Share","type":"->"},{"function":"OCA\\Deck\\Service\\{closure}","class":"OCA\\Deck\\Service\\FilesAppService","type":"->","args":["*** sensitive parameters replaced ***"]},{"file":"/var/www/tech-preview.nextcloud.com/apps/deck/lib/Service/FilesAppService.php","line":82,"function":"array_map"},{"file":"/var/www/tech-preview.nextcloud.com/apps/deck/lib/Service/AttachmentService.php","line":121,"function":"listAttachments","class":"OCA\\Deck\\Service\\FilesAppService","type":"->"},{"file":"/var/www/tech-preview.nextcloud.com/apps/deck/lib/Controller/AttachmentController.php","line":44,"function":"findAll","class":"OCA\\Deck\\Service\\AttachmentService","type":"->"},{"file":"/var/www/tech-preview.nextcloud.com/lib/private/AppFramework/Http/Dispatcher.php","line":217,"function":"getAll","class":"OCA\\Deck\\Controller\\AttachmentController","type":"->"},{"file":"/var/www/tech-preview.nextcloud.com/lib/private/AppFramework/Http/Dispatcher.php","line":126,"function":"executeController","class":"OC\\AppFramework\\Http\\Dispatcher","type":"->"},{"file":"/var/www/tech-preview.nextcloud.com/lib/private/AppFramework/App.php","line":156,"function":"dispatch","class":"OC\\AppFramework\\Http\\Dispatcher","type":"->"},{"file":"/var/www/tech-preview.nextcloud.com/lib/private/Route/Router.php","line":301,"function":"main","class":"OC\\AppFramework\\App","type":"::"},{"file":"/var/www/tech-preview.nextcloud.com/lib/base.php","line":1000,"function":"match","class":"OC\\Route\\Router","type":"->"},{"file":"/var/www/tech-preview.nextcloud.com/index.php","line":36,"function":"handleRequest","class":"OC","type":"::"}],"File":"/var/www/tech-preview.nextcloud.com/lib/private/Share20/Share.php","Line":190,"CustomMessage":"--"},"id":"6130ffca5e631"}

I have a video: https://cloud.nextcloud.com/s/wkSRCWPHcjqXXw2
an admin login for the server can be found here: https://cloud.nextcloud.com/index.php/f/3406050
(try username jos, same pw as other users...)

Start by reproducing the sharing sequence and inspect the logged failure in apps/deck/lib/Service/FilesAppService.php, then follow AttachmentService.php and AttachmentController.php. The attachment endpoint should no longer leave an invisible attachment after the shared file or conversation share is revoked.