Merge pull request #50769 from nextcloud/checkStorageIdSetCache

fix(SharedStorage): Check if storage ID is set on cache

apps/files_sharing/lib/SharedStorage.php

@@ -438,16 +438,15 @@ public function getWatcher(string $path = '', ?IStorage $storage = null): IWatch
 		// Get node information
 		$node = $this->getShare()->getNodeCacheEntry();
 		if ($node instanceof CacheEntry) {
-			$storageId = $node->getData()['storage_string_id'];
+			$storageId = $node->getData()['storage_string_id'] ?? null;
 			// for shares from the home storage we can rely on the home storage to keep itself up to date
 			// for other storages we need use the proper watcher
-			if (!(str_starts_with($storageId, 'home::') || str_starts_with($storageId, 'object::user'))) {
+			if ($storageId !== null && !(str_starts_with($storageId, 'home::') || str_starts_with($storageId, 'object::user'))) {
 				$cache = $this->getCache();
 				$this->watcher = parent::getWatcher($path, $storage);
 				if ($cache instanceof Cache) {
 					$this->watcher->onUpdate($cache->markRootChanged(...));
 				}
-
 				return $this->watcher;
 			}
 		}