nextcloud / server

					$results[] = array_reduce($users, function(array $carry, IUser $user) use ($restrictGroups) {

						// is sharing restricted to groups only?

						if ($restrictGroups !== false) {

							$userGroups = $this->groupManager->getUserGroupIds($user);

							if (count(array_intersect($userGroups, $restrictGroups)) === 0) {

								return $carry;

							}

						}

						$carry[] = $this->principalPrefix . '/' . $user->getUID();

						return $carry;

				}

				$user = $users[0];

				if ($restrictGroups !== false) {

					$userGroups = $this->groupManager->getUserGroupIds($user);

					if (count(array_intersect($userGroups, $restrictGroups)) === 0) {

						return null;

					}

				}

				return $this->principalPrefix . '/' . $user->getUID();

			}