fix(dav): use absolute cutoff for sync token pruning

Signed-off-by: mooons <10822203+mooons@users.noreply.github.com>

Author: mooons

apps/dav/lib/CalDAV/CalDavBackend.php

@@ -3619,11 +3619,13 @@ public function pruneOutdatedSyncTokens(int $keep, int $retention): int {
 			return 0;
 		}
 
+		$cutoff = max(0, time() - $retention);
+
 		$query = $this->db->getQueryBuilder();
 		$query->delete('calendarchanges')
 			->where(
 				$query->expr()->lte('id', $query->createNamedParameter($maxId - $keep, IQueryBuilder::PARAM_INT), IQueryBuilder::PARAM_INT),
-				$query->expr()->lte('created_at', $query->createNamedParameter($retention)),
+				$query->expr()->lte('created_at', $query->createNamedParameter($cutoff, IQueryBuilder::PARAM_INT), IQueryBuilder::PARAM_INT),
 			);
 		return $query->executeStatement();
 	}

apps/dav/lib/CardDAV/CardDavBackend.php

@@ -1496,11 +1496,13 @@ public function pruneOutdatedSyncTokens(int $keep, int $retention): int {
 			return 0;
 		}
 
+		$cutoff = max(0, time() - $retention);
+
 		$query = $this->db->getQueryBuilder();
 		$query->delete('addressbookchanges')
 			->where(
 				$query->expr()->lte('id', $query->createNamedParameter($maxId - $keep, IQueryBuilder::PARAM_INT), IQueryBuilder::PARAM_INT),
-				$query->expr()->lte('created_at', $query->createNamedParameter($retention)),
+				$query->expr()->lte('created_at', $query->createNamedParameter($cutoff, IQueryBuilder::PARAM_INT), IQueryBuilder::PARAM_INT),
 			);
 		return $query->executeStatement();
 	}