[stable34] fix: add promoteToOwner method

lib/Db/MemberRequest.php

@@ -20,13 +20,25 @@
 use OCA\Circles\Model\Member;
 use OCA\Circles\Model\Probes\CircleProbe;
 use OCA\Circles\Model\Probes\MemberProbe;
+use OCA\Circles\Service\ConfigService;
+use OCA\Circles\Service\TimezoneService;
+use OCP\IDBConnection;
 
 /**
  * Class MemberRequest
  *
  * @package OCA\Circles\Db
  */
 class MemberRequest extends MemberRequestBuilder {
+
+	public function __construct(
+		private IDBConnection $db,
+		TimezoneService $timezoneService,
+		ConfigService $configService,
+	) {
+		parent::__construct($timezoneService, $configService);
+	}
+
 	/**
 	 * @param Member $member
 	 *
@@ -186,6 +198,42 @@ public function updateLevel(Member $member): void {
 	}
 
 
+	/**
+	 * @return ?Member old owner or null if old owner was not found
+	 */
+	public function promoteToOwner(Member $member): ?Member {
+		try {
+			$this->db->beginTransaction();
+
+			$qb = $this->getMemberSelectSql();
+			$qb->limitToCircleId($member->getCircleId());
+			$qb->limitInt('level', Member::LEVEL_OWNER);
+			// forUpdate locks the owner row until transaction is commited, forcing concurrent
+			// requests to wait and read the updated current owner, preventing multiple owners
+			$qb->forUpdate();
+
+			try {
+				$oldOwner = $this->getItemFromRequest($qb);
+			} catch (MemberNotFoundException) {
+				$oldOwner = null;
+			}
+
+			$this->updateLevel($member);
+
+			if ($oldOwner !== null && $oldOwner->getId() !== $member->getId()) {
+				$oldOwner->setLevel(Member::LEVEL_ADMIN);
+				$this->updateLevel($oldOwner);
+			}
+
+			$this->db->commit();
+
+			return $oldOwner;
+		} catch (\Throwable $e) {
+			$this->db->rollBack();
+			throw $e;
+		}
+	}
+
 	/**
 	 * @param string $singleId
 	 * @param IFederatedUser|null $initiator

lib/FederatedItems/MemberLevel.php

@@ -125,13 +125,14 @@ public function verify(FederatedEvent $event): void {
 	public function manage(FederatedEvent $event): void {
 		$member = clone $event->getMember();
 		$member->setLevel($event->getData()->gInt('level'));
-		$this->memberRequest->updateLevel($member);
 
 		if ($member->getLevel() === Member::LEVEL_OWNER) {
-			$oldOwner = clone $event->getCircle()->getOwner();
-			$oldOwner->setLevel(Member::LEVEL_ADMIN);
-			$this->memberRequest->updateLevel($oldOwner);
-			$this->membershipService->onUpdate($oldOwner->getSingleId());
+			$oldOwner = $this->memberRequest->promoteToOwner($member);
+			if ($oldOwner !== null) {
+				$this->membershipService->onUpdate($oldOwner->getSingleId());
+			}
+		} else {
+			$this->memberRequest->updateLevel($member);
 		}
 
 		$this->membershipService->onUpdate($member->getSingleId());