1 files changed, 24 insertions, 6 deletions

diff --git a/lib/private/Group/Manager.php b/lib/private/Group/Manager.php
index 944598a8296..40009dbfd80 100644
--- a/lib/private/Group/Manager.php
+++ b/lib/private/Group/Manager.php
@@ -37,7 +37,10 @@ namespace OC\Group;
 
 use OC\Hooks\PublicEmitter;
 use OCP\GroupInterface;
+use OCP\IGroup;
 use OCP\IGroupManager;
+use OCP\ILogger;
+use OCP\IUser;
 
 /**
  * Class Manager
@@ -78,11 +81,16 @@ class Manager extends PublicEmitter implements IGroupManager {
 	/** @var \OC\SubAdmin */
 	private $subAdmin = null;
 
+	/** @var ILogger */
+	private $logger;
+
 	/**
 	 * @param \OC\User\Manager $userManager
+	 * @param ILogger $logger
 	 */
-	public function __construct(\OC\User\Manager $userManager) {
+	public function __construct(\OC\User\Manager $userManager, ILogger $logger) {
 		$this->userManager = $userManager;
+		$this->logger = $logger;
 		$cachedGroups = & $this->cachedGroups;
 		$cachedUserGroups = & $this->cachedUserGroups;
 		$this->listen('\OC\Group', 'postDelete', function ($group) use (&$cachedGroups, &$cachedUserGroups) {
@@ -186,7 +194,7 @@ class Manager extends PublicEmitter implements IGroupManager {
 	 * @return bool
 	 */
 	public function groupExists($gid) {
-		return !is_null($this->get($gid));
+		return $this->get($gid) instanceof IGroup;
 	}
 
 	/**
@@ -194,7 +202,7 @@ class Manager extends PublicEmitter implements IGroupManager {
 	 * @return \OC\Group\Group
 	 */
 	public function createGroup($gid) {
-		if ($gid === '' || is_null($gid)) {
+		if ($gid === '' || $gid === null) {
 			return false;
 		} else if ($group = $this->get($gid)) {
 			return $group;
@@ -223,7 +231,12 @@ class Manager extends PublicEmitter implements IGroupManager {
 		foreach ($this->backends as $backend) {
 			$groupIds = $backend->getGroups($search, $limit, $offset);
 			foreach ($groupIds as $groupId) {
-				$groups[$groupId] = $this->get($groupId);
+				$aGroup = $this->get($groupId);
+				if ($aGroup instanceof IGroup) {
+					$groups[$groupId] = $aGroup;
+				} else {
+					$this->logger->debug('Group "' . $groupId . '" was returned by search but not found through direct access', ['app' => 'core']);
+				}
 			}
 			if (!is_null($limit) and $limit <= 0) {
 				return array_values($groups);
@@ -237,7 +250,7 @@ class Manager extends PublicEmitter implements IGroupManager {
 	 * @return \OC\Group\Group[]
 	 */
 	public function getUserGroups($user) {
-		if (is_null($user)) {
+		if (!$user instanceof IUser) {
 			return [];
 		}
 		return $this->getUserIdGroups($user->getUID());
@@ -256,7 +269,12 @@ class Manager extends PublicEmitter implements IGroupManager {
 			$groupIds = $backend->getUserGroups($uid);
 			if (is_array($groupIds)) {
 				foreach ($groupIds as $groupId) {
-					$groups[$groupId] = $this->get($groupId);
+					$aGroup = $this->get($groupId);
+					if ($aGroup instanceof IGroup) {
+						$groups[$groupId] = $aGroup;
+					} else {
+						$this->logger->debug('User "' . $uid . '" belongs to deleted group: "' . $groupId . '"', ['app' => 'core']);
+					}
 				}
 			}
 		}