From 488ed2863544d6d8819c812bd85a3632d5545d41 Mon Sep 17 00:00:00 2001
From: Nick Craig-Wood <nick@craig-wood.com>
Date: Wed, 15 May 2024 15:55:05 +0100
Subject: [PATCH] fs: fix panic when using --metadata-mapper on large google
 doc files

Before this change, attempting to copy a large google doc while using
the metadata mapper caused a panic. Google doc files use Rcat to
download as they have an unknown size, and when the size of the doc
file got above --streaming-upload-cutoff it used a
object.NewStaticObjectInfo with a `nil` Fs to upload the file which
caused the crash in the metadata mapper code.

This change makes sure that the Fs in object.NewStaticObjectInfo is
never nil, and it returns MemoryFs which is consistent with the Rcat
code when the source is sized below the --streaming-upload-cutoff
threshold.

Fixes #7845
---
 fs/object/object.go      | 3 +++
 fs/object/object_test.go | 1 +
 2 files changed, 4 insertions(+)

diff --git a/fs/object/object.go b/fs/object/object.go
index 93c923681..01b38f57a 100644
--- a/fs/object/object.go
+++ b/fs/object/object.go
@@ -43,6 +43,9 @@ func NewStaticObjectInfo(remote string, modTime time.Time, size int64, storable
 			info.hashes[ht] = ""
 		}
 	}
+	if f == nil {
+		info.fs = MemoryFs
+	}
 	return info
 }
 
diff --git a/fs/object/object_test.go b/fs/object/object_test.go
index 1e5ca75c4..64bb36140 100644
--- a/fs/object/object_test.go
+++ b/fs/object/object_test.go
@@ -34,6 +34,7 @@ func TestStaticObject(t *testing.T) {
 	o = object.NewStaticObjectInfo(remote, now, size, true, nil, nil)
 	_, err = o.Hash(context.Background(), hash.MD5)
 	assert.Equal(t, hash.ErrUnsupported, err)
+	assert.Equal(t, object.MemoryFs, o.Fs())
 
 	hs := map[hash.Type]string{
 		hash.MD5: "potato",