Merge pull request #5464 from nextcloud/shared-cache-during-init-11

[11] dont die if we try to access the shared cache while setting up the shared storage

apps/files_sharing/lib/Cache.php

@@ -27,6 +27,7 @@
 
 namespace OCA\Files_Sharing;
 
+use OC\Files\Cache\FailedCache;
 use OC\Files\Cache\Wrapper\CacheJail;
 use OCP\Files\Cache\ICacheEntry;
 use OCP\Files\Storage\IStorage;
@@ -66,7 +67,13 @@ public function __construct($storage, ICacheEntry $sourceRootInfo) {
 
 	public function getCache() {
 		if (is_null($this->cache)) {
-			$this->cache = $this->storage->getSourceStorage()->getCache();
+			$sourceStorage = $this->storage->getSourceStorage();
+			if ($sourceStorage) {
+				$this->cache = $sourceStorage->getCache();
+			} else {
+				// don't set $this->cache here since sourceStorage will be set later
+				return new FailedCache();
+			}
 		}
 		return $this->cache;
 	}