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

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?