fix: Add command to update re-share if shared-by user has been revoked

[luka-nextcloud]

• Resolves: [Bug]: Sub folder shares were broken on ownership transfer #42407

Summary

Add command occ sharing:fix-broken-shares to fix the shares that were broken on transfer ownership.

Checklist

• Tests (unit, integration, api and/or acceptance) are included
• Screenshots before/after for front-end changes
• Documentation (manuals or wiki) has been updated or is not required
• Backports requested where applicable (ex: critical bugfixes)

[luka-nextcloud]

Another effected case by this issue:

1. UserA share Folder1 to UserB
2. UserB share Folder1 to UserC
3. UserA revoke UserB
4. UserA try to update sharing permission of UserC
   -> Error: Could not get proper share mount for . Failing since else the next calls are called with null

[luka-nextcloud]

@artonge I've updated as you requested, please check again.

[artonge]

Can you add comments to clarify what each if group does?

I am also wondering if we could find this shares with the following query:

SELECT
	f.fileid,
	f.path,
	f.storage,
	s.id as share_id,
	s.uid_owner as share_owner,
	s.uid_initiator as share_initiator,
	s.share_with as share_recipient
FROM
	oc_filecache f
	JOIN oc_share s ON f.fileid = s.file_source
	AND s.uid_initiator NOT IN (
		SELECT
			user_id
		FROM
			oc_mounts m
		WHERE
			f.storage = m.storage_id
	)

If so, then we could have a background job to remove them every hour or so like https://github.com/nextcloud/server/blob/master/apps/files_sharing/lib/DeleteOrphanedSharesJob.php, which might be easier than the current solution.

[luka-nextcloud]

Can you add comments to clarify what each if group does?

I am also wondering if we could find this shares with the following query:

SELECT
	f.fileid,
	f.path,
	f.storage,
	s.id as share_id,
	s.uid_owner as share_owner,
	s.uid_initiator as share_initiator,
	s.share_with as share_recipient
FROM
	oc_filecache f
	JOIN oc_share s ON f.fileid = s.file_source
	AND s.uid_initiator NOT IN (
		SELECT
			user_id
		FROM
			oc_mounts m
		WHERE
			f.storage = m.storage_id
	)

If so, then we could have a background job to remove them every hour or so like https://github.com/nextcloud/server/blob/master/apps/files_sharing/lib/DeleteOrphanedSharesJob.php, which might be easier than the current solution.

@artonge It only works if the shared-by user refreshes his files list after his share has revoked. So, I don't think this query would do the job.

[luka-nextcloud]

/backport to stable28

[luka-nextcloud]

/backport to stable29

[luka-nextcloud]

/backport to stable30