Issue with Accessing String Offset on getParticipant() Return Value in PermissionHelperService

[WallastonLouis]

I've encountered an issue within the PermissionHelperService class of our Nextcloud Health app, specifically when trying to access the getParticipant() method's return value. The error message encountered is:

Exception: Cannot access offset of type string on string in file '/var/www/nextcloud/apps/health/lib/Services/PermissionHelperService.php' on line 89.

Upon reviewing the code, it seems that the method getParticipant() is expected to return an array or an object that includes a "uid" key. However, the actual return value appears to be a string. This discrepancy leads to a critical error when attempting to access the "uid" offset as if the return value were an array or an object.

Here is the problematic segment of the code for your reference:

public function getSharedPersonsOfCurrentUser(array $acls): array {
$personIds = array();
foreach($acls as $acl) {
if ($acl->getType() == Acl::PERMISSION_TYPE_USER && $acl->getParticipant()["uid"] == $this->userId) {
$personIds[] = $acl->getPersonId();
}
if ($acl->getType() == Acl::PERMISSION_TYPE_GROUP && $this->groupManager->isInGroup($this->userId, $acl->getParticipant()["uid"])) {
$personIds[] = $acl->getPersonId();
}
}
...
}