From ffd11662babcf0a2d2562ba104a4276ac8b47fd2 Mon Sep 17 00:00:00 2001
From: Nick Craig-Wood <nick@craig-wood.com>
Date: Tue, 31 Jul 2018 11:22:45 +0100
Subject: [PATCH] cache: fix nil pointer deref when using lsjson on cached
 directory

This stops embedding the fs.Directory into the cache.Directory because
it can be nil and implements an ID method which checks the nil status.

See: https://forum.rclone.org/t/runtime-error-with-cache-remote-and-lsjson/6305
---
 backend/cache/directory.go | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/backend/cache/directory.go b/backend/cache/directory.go
index 658dbda72..863612758 100644
--- a/backend/cache/directory.go
+++ b/backend/cache/directory.go
@@ -12,7 +12,7 @@ import (
 
 // Directory is a generic dir that stores basic information about it
 type Directory struct {
-	fs.Directory `json:"-"`
+	Directory fs.Directory `json:"-"` // can be nil
 
 	CacheFs      *Fs    `json:"-"`       // cache fs
 	Name         string `json:"name"`    // name of the directory
@@ -125,6 +125,14 @@ func (d *Directory) Items() int64 {
 	return d.CacheItems
 }
 
+// ID returns the ID of the cached directory if known
+func (d *Directory) ID() string {
+	if d.Directory == nil {
+		return ""
+	}
+	return d.Directory.ID()
+}
+
 var (
 	_ fs.Directory = (*Directory)(nil)
 )