Merge pull request #17060 from nextcloud/backport/16985/stable17

[stable17] Properly initialize the CacheJail for sharing

Author: rullzer

apps/files_sharing/lib/Cache.php

@@ -67,12 +67,12 @@ public function __construct($storage, ICacheEntry $sourceRootInfo) {
 
 		parent::__construct(
 			null,
-			null
+			''
 		);
 	}
 
 	protected function getRoot() {
-		if (is_null($this->root)) {
+		if ($this->root === '') {
 			$absoluteRoot = $this->sourceRootInfo->getPath();
 
 			// the sourceRootInfo path is the absolute path of the folder in the "real" storage
@@ -138,7 +138,7 @@ public function moveFromCache(\OCP\Files\Cache\ICache $sourceCache, $sourcePath,
 
 	protected function formatCacheEntry($entry, $path = null) {
 		if (is_null($path)) {
-			$path = isset($entry['path']) ? $entry['path'] : '';
+			$path = $entry['path'] ?? '';
 			$entry['path'] = $this->getJailedPath($path);
 		} else {
 			$entry['path'] = $path;