recreate an etag within the scanner if the cache contains an empty etag

1 files changed, 7 insertions, 1 deletions

diff --git a/lib/files/cache/scanner.php b/lib/files/cache/scanner.php
index 9d180820e9d..78cab6ed2da 100644
--- a/lib/files/cache/scanner.php
+++ b/lib/files/cache/scanner.php
@@ -97,13 +97,19 @@ class Scanner extends BasicEmitter {
 				}
 				$newData = $data;
 				if ($reuseExisting and $cacheData = $this->cache->get($file)) {
+					// prevent empty etag
+					$etag = $cacheData['etag'];
+					if (empty($etag)) {
+						$etag = $data['etag'];
+					}
+
 					// only reuse data if the file hasn't explicitly changed
 					if (isset($data['mtime']) && isset($cacheData['mtime']) && $data['mtime'] === $cacheData['mtime']) {
 						if (($reuseExisting & self::REUSE_SIZE) && ($data['size'] === -1)) {
 							$data['size'] = $cacheData['size'];
 						}
 						if ($reuseExisting & self::REUSE_ETAG) {
-							$data['etag'] = $cacheData['etag'];
+							$data['etag'] = $etag;
 						}
 					}
 					// Only update metadata that has changed