new user cannot access file on external storage

[individual-it]

with Encryption type: User Specific Key

1. enable external storage and connect /local_storage
2. create user1 & user2
3. as user1 create a file on /local_storage
4. make sure user2 can read the file
5. create user3
6. try to access the file as user3

{"reqId":"bOFbmO81PcSHHxrXVGeD","level":3,"time":"2018-08-14T10:57:53+00:00","remoteAddr":"127.0.0.1","user":"uu3","app":"no app in context","method":"GET","url":"\/owncloud-core\/remote.php\/dav\/files\/uu3\/local_storage\/new-folder\/New%20text%20file.txt?c=2147484153null&x=32&y=32&forceIcon=0&preview=1","message":"Can not decrypt this file, probably this is a shared file. Please ask the file owner to reshare the file with you."}

[PVince81]

assuming you mounted the external storage with access for "all users".

This is a known limitation of encryption, like owncloud/core#16332.
We can't setup the share key for user3 as we'd need the password of user1 or user2 to do so (or anyone who already has access to the file).

Won't fix, should be part of owncloud-archive/documentation#4179