Merge pull request #26081 from nextcloud/backport/26080/stable21

[stable21] Only clear known users when we had at least one phonebook entry

Author: rullzer

apps/provisioning_api/lib/Controller/UsersController.php

@@ -239,9 +239,6 @@ public function searchByPhoneNumbers(string $location, array $search): DataRespo
 		$user = $this->userSession->getUser();
 		$knownTo = $user->getUID();
 
-		// Cleanup all previous entries and only allow new matches
-		$this->knownUserService->deleteKnownTo($knownTo);
-
 		$normalizedNumberToKey = [];
 		foreach ($search as $key => $phoneNumbers) {
 			foreach ($phoneNumbers as $phone) {
@@ -262,6 +259,9 @@ public function searchByPhoneNumbers(string $location, array $search): DataRespo
 			return new DataResponse();
 		}
 
+		// Cleanup all previous entries and only allow new matches
+		$this->knownUserService->deleteKnownTo($knownTo);
+
 		$userMatches = $this->accountManager->searchUsers(IAccountManager::PROPERTY_PHONE, $phoneNumbers);
 
 		if (empty($userMatches)) {