Fix getting the information of a group share as a sharee

[danxuliu]

When the receiver of a group share modifies it (for example, by moving it to a different folder) the original share is not modified, but a "ghost" share that keeps track of the changes made by that specific user is used instead.

By default, the method getShareById in the share provider returns the share from the point of view of the sharer, but it can be used too to get the share from the point of view of a sharee by providing the recipient parameter (and if the sharee is not found then the share is returned from the point of view of the sharer).

The ShareAPIController always formats the share from the point of view of the current user, but when getting the information of a specific share the recipient parameter was not given, so it was always returned from the point of view of the sharer, even if the current user was a sharee. Now the recipient parameter is set to the current user, and thus the information of the share is returned from the point of view of the current user, be it the sharer or a sharee.

All this can be seen in the integration tests added also in this pull request; without the fix, when getting the information of a group share as a sharee, the returned file_target is /textfile0.txt instead of /textfile0 (2).txt (because it is returned by getShareById), but the returned path is /textfile0 (2).txt with and without the fix (because it is got from the node as the current user when the share is formatted).

Note that this special behaviour of getShareById happens only with group shares; with other types of shares the share is the same for the sharer and the sharee, and thus the parameter is ignored (DefaultShareProvider, ShareByCircleProvider, ShareByMailProvider and FederatedShareProvider); it was added for them too just for consistency.

[MorrisJobke]

This one is not related, right?

1) OCA\Files_Sharing\Tests\ShareTest::testShareWithGroupUniqueName
OCP\Files\NotFoundException: Node for share not found, fileid: 2653

/drone/src/github.com/nextcloud/server/lib/private/Share20/Share.php:168
/drone/src/github.com/nextcloud/server/lib/private/Share20/Manager.php:254
/drone/src/github.com/nextcloud/server/lib/private/Share20/Manager.php:808
/drone/src/github.com/nextcloud/server/apps/files_sharing/tests/ShareTest.php:186

Or should it fix that one?

[danxuliu]

No, it is not related; that is a different issue.

[MorrisJobke]

Makes sense 👍

[rullzer]

Indeed makes sense.