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

[Richard W.M. Jones]

On Wed, Aug 22, 2018 at 01:20:55PM +0200, Pino Toscano wrote:
> On Monday, 20 August 2018 18:02:06 CEST Richard W.M. Jones wrote:
> > -  } else
> > -    rv = Val_none;
> > +  }
> > +  else {
> > +    /* Previously we had a special JSON_parser_null value we could
> > +     * use here, making the returned type (sort of) an option.
> > +     * This is a best effort which is better than crashing /
> > +     * throwing an error.
> > +     */
> > +    rv = caml_alloc (1, JSON_STRING_TAG);
> > +    v = caml_copy_string ("");
> > +    Store_field (rv, 0, v);
> > +  }
> 
> 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?

Rich.

-- 
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
Read my programming and virtualization blog: http://rwmj.wordpress.com
virt-p2v converts physical machines to virtual machines.  Boot with a
live CD or over the network (PXE) and turn machines into KVM guests.
http://libguestfs.org/virt-v2v