Merge pull request #7109 from nextcloud/fix_6898

If for some reason the json can't be decoded it is not cached

lib/private/Template/JSCombiner.php

@@ -119,6 +119,10 @@ class JSCombiner {
 
 			$deps = json_decode($deps, true);
 
+			if ($deps === NULL) {
+				return false;
+			}
+
 			foreach ($deps as $file=>$mtime) {
 				if (!file_exists($file) || filemtime($file) > $mtime) {
 					return false;