[stable28] Bug fix: Select the correct table based on CALENDAR_TYPE_CALENDAR

apps/dav/lib/CalDAV/CalDavBackend.php

@@ -2341,86 +2341,88 @@
 	 * @return array
 	 */
 	public function getChangesForCalendar($calendarId, $syncToken, $syncLevel, $limit = null, $calendarType = self::CALENDAR_TYPE_CALENDAR) {
-		return $this->atomic(function () use ($calendarId, $syncToken, $syncLevel, $limit, $calendarType) {
+		$table = $calendarType === self::CALENDAR_TYPE_CALENDAR ? 'calendars': 'calendarsubscriptions';
+
+		return $this->atomic(function () use ($calendarId, $syncToken, $syncLevel, $limit, $calendarType, $table) {
 			// Current synctoken
 			$qb = $this->db->getQueryBuilder();
 			$qb->select('synctoken')
-				->from('calendars')
+				->from($table)
 				->where(
 					$qb->expr()->eq('id', $qb->createNamedParameter($calendarId))
 				);
 			$stmt = $qb->executeQuery();
 			$currentToken = $stmt->fetchOne();
 
 			if ($currentToken === false) {
 				return null;
 			}
 
 			$result = [
 				'syncToken' => $currentToken,
 				'added' => [],
 				'modified' => [],
 				'deleted' => [],
 			];
 
 			if ($syncToken) {
 				$qb = $this->db->getQueryBuilder();
 
 				$qb->select('uri', 'operation')
 					->from('calendarchanges')
 					->where(
 						$qb->expr()->andX(
 							$qb->expr()->gte('synctoken', $qb->createNamedParameter($syncToken)),
 							$qb->expr()->lt('synctoken', $qb->createNamedParameter($currentToken)),
 							$qb->expr()->eq('calendarid', $qb->createNamedParameter($calendarId)),
 							$qb->expr()->eq('calendartype', $qb->createNamedParameter($calendarType))
 						)
 					)->orderBy('synctoken');
 				if (is_int($limit) && $limit > 0) {
 					$qb->setMaxResults($limit);
 				}
 
 				// Fetching all changes
 				$stmt = $qb->executeQuery();
 				$changes = [];
 
 				// This loop ensures that any duplicates are overwritten, only the
 				// last change on a node is relevant.
 				while ($row = $stmt->fetch()) {
 					$changes[$row['uri']] = $row['operation'];
 				}
 				$stmt->closeCursor();
 
 				foreach ($changes as $uri => $operation) {
 					switch ($operation) {
 						case 1:
 							$result['added'][] = $uri;
 							break;
 						case 2:
 							$result['modified'][] = $uri;
 							break;
 						case 3:
 							$result['deleted'][] = $uri;
 							break;
 					}
 				}
 			} else {
 				// No synctoken supplied, this is the initial sync.
 				$qb = $this->db->getQueryBuilder();
 				$qb->select('uri')
 					->from('calendarobjects')
 					->where(
 						$qb->expr()->andX(
 							$qb->expr()->eq('calendarid', $qb->createNamedParameter($calendarId)),
 							$qb->expr()->eq('calendartype', $qb->createNamedParameter($calendarType))
 						)
 					);
 				$stmt = $qb->executeQuery();
 				$result['added'] = $stmt->fetchAll(\PDO::FETCH_COLUMN);
 				$stmt->closeCursor();
 			}
 			return $result;
 		}, $this->db);
 	}
 
 	/**