Demonstration of hard to debug caching problem when device is from no longer valid device graph

disk-devicegraph.xml

<?xml version="1.0"?>
<Devicegraph>
  <Devices>
    <Disk>
      <sid>42</sid>
      <name>/dev/sda</name>
      <sysfs-name>sda</sysfs-name>
      <sysfs-path>/devices/pci0000:00/0000:00:1f.2/ata1/host0/target0:0:0/0:0:0:0/block/sda</sysfs-path>
      <region>
        <length>16777216</length>
        <block-size>512</block-size>
      </region>
      <udev-path>pci-0000:00:1f.2-ata-1.0</udev-path>
      <udev-id>ata-VBOX_HARDDISK_VB3b96ac9d-f9f14bd2</udev-id>
      <udev-id>scsi-0ATA_VBOX_HARDDISK_VB3b96ac9d-f9f14bd2</udev-id>
      <udev-id>scsi-1ATA_VBOX_HARDDISK_VB3b96ac9d-f9f14bd2</udev-id>
      <udev-id>scsi-SATA_VBOX_HARDDISK_VB3b96ac9d-f9f14bd2</udev-id>
      <topology/>
      <range>256</range>
      <transport>SATA</transport>
    </Disk>
  </Devices>
</Devicegraph>

test.rb

require "storage"

env = Storage::Environment.new(1, Storage::ProbeMode_READ_DEVICEGRAPH, Storage::TargetMode_DIRECT)
env.devicegraph_filename = "./disk-devicegraph.xml"

storage = Storage::Storage.new(env)
storage.probe

graph = storage.probed
disk = graph.all_disks.to_a.first

storage.probe # this cause invalidation of disk
disk.name