[stable9] getJailedPath expects $path to have a trailing / (#25703) (#25738)

* getJailedPath expects $path to have a trailing / - fixes #25464

* Adding test case for getPathById including a jailed cache where root is just empty

1 files changed, 3 insertions, 0 deletions

diff --git a/lib/private/files/cache/wrapper/cachejail.php b/lib/private/files/cache/wrapper/cachejail.php
index 65275bcb798..83329bbbd9c 100644
--- a/lib/private/files/cache/wrapper/cachejail.php
+++ b/lib/private/files/cache/wrapper/cachejail.php
@@ -56,6 +56,9 @@ class CacheJail extends CacheWrapper {
 	 * @return null|string the jailed path or null if the path is outside the jail
 	 */
 	protected function getJailedPath($path) {
+		if ($this->root === '') {
+			return $path;
+		}
 		$rootLength = strlen($this->root) + 1;
 		if ($path === $this->root) {
 			return '';