3 files changed, 39 insertions, 2 deletions
diff --git a/lib/public/Group/Backend/ABackend.php b/lib/public/Group/Backend/ABackend.php
index 7f5cf732335..e76285dfda9 100644
--- a/lib/public/Group/Backend/ABackend.php
+++ b/lib/public/Group/Backend/ABackend.php
@@ -26,6 +26,10 @@ declare(strict_types=1);
 namespace OCP\Group\Backend;
 
 use OCP\GroupInterface;
+use OCP\IUserManager;
+use OCP\Server;
+use OC\User\LazyUser;
+use OC\User\DisplayNameCache;
 
 /**
  * @since 14.0.0
@@ -65,4 +69,15 @@ abstract class ABackend implements GroupInterface {
 
 		return (bool)($actions & $implements);
 	}
+
+	public function searchInGroup(string $gid, string $search = '', int $limit = -1, int $offset = 0): array {
+		// Default implementation for compatibility reasons
+		$displayNameCache = Server::get(DisplayNameCache::class);
+		$userManager = Server::get(IUserManager::class);
+		$users = [];
+		foreach ($this->usersInGroup($gid, $search, $limit, $offset) as $userId) {
+			$users[$userId] = new LazyUser($userId, $displayNameCache, $userManager);
+		}
+		return $users;
+	}
 }
diff --git a/lib/public/GroupInterface.php b/lib/public/GroupInterface.php
index b7c07136126..07fd5cb50c4 100644
--- a/lib/public/GroupInterface.php
+++ b/lib/public/GroupInterface.php
@@ -106,13 +106,35 @@ interface GroupInterface {
 	public function groupExists($gid);
 
 	/**
-	 * get a list of all users in a group
+	 * @brief Get a list of user ids in a group matching the given search parameters.
+	 *
 	 * @param string $gid
 	 * @param string $search
 	 * @param int $limit
 	 * @param int $offset
 	 * @return array an array of user ids
 	 * @since 4.5.0
+	 * @deprecated 25.0.0 Use searchInGroup instead, for performance reasons
 	 */
 	public function usersInGroup($gid, $search = '', $limit = -1, $offset = 0);
+
+	/**
+	 * @brief Get a list of users matching the given search parameters.
+	 *
+	 * Implementations of this method should return lazy evaluated user objects and
+	 * preload if possible the display name.
+	 *
+	 * <code>
+	 * $users = $groupBackend->searchInGroup('admin', 'John', 10, 0);
+	 * </code>
+	 *
+	 * @param string $gid    The group id of the user we want to search
+	 * @param string $search The part of the display name or user id of the users we
+	 *                       want to search. This can be empty to get all the users.
+	 * @param int $limit     The limit of results
+	 * @param int $offset    The offset of the results
+	 * @return IUser[]
+	 * @since 25.0.0
+	 */
+	public function searchInGroup(string $gid, string $search = '', int $limit = -1, int $offset = 0): array;
 }
diff --git a/lib/public/IGroup.php b/lib/public/IGroup.php
index ba13359c472..ec26cc55b69 100644
--- a/lib/public/IGroup.php
+++ b/lib/public/IGroup.php
@@ -99,7 +99,7 @@ interface IGroup {
 	 * @return \OCP\IUser[]
 	 * @since 8.0.0
 	 */
-	public function searchUsers($search, $limit = null, $offset = null);
+	public function searchUsers(string $search, ?int $limit = null, ?int $offset = null): array;
 
 	/**
 	 * returns the number of users matching the search string