[Libguestfs] [PATCH 4/4] mltools: JSON: unify JSON_parser type with JSON.json_t.

[Eric Blake]

On 08/22/2018 09:18 AM, Richard W.M. Jones wrote:

>> NACK, this is not correct.  null is a proper type of value in JSON, and
>> thus JSON.json_t must represent it as well.
>>
>> This is even used in other parts, for example the check of backing
>> files of disks (see guestfs_impl_disk_has_backing_file).
> 
> Can you explain more about what a "null" JSON document looks like?

An example: qemu will accept the following substring, as part of 
BlockdevOptionsGenricCOWFormat, when specifically asking qemu to ignore 
the backing information present in a file and instead open the file 
without any backing:

{ "backing": null }

That is, JSON has "null", "true", and "false" as its three bare 
literals, which hold the same semantic weight as literal numbers, 
strings, [] arrays, and {} objects.

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3266
Virtualization:  qemu.org | libvirt.org