Re: [Qemu-devel] [PATCH for-2.10 10/10] migration: Use JSON null instead of "" to reset parameter to default

[Markus Armbruster <armbru@redhat.com>]

Eric Blake <eblake@redhat.com> writes:

> On 07/18/2017 01:39 PM, Markus Armbruster wrote:
>
>>>> +++ b/qapi-schema.json
>>>> @@ -116,6 +116,13 @@
>>>>  { 'command': 'qmp_capabilities' }
>>>>  
>>>>  ##
>>>> +# @StrOrNull:
>>>
>>> A little light on the documentation.
>> 
>> Care to suggest improvements?  I figure the schema is obvious enough
>> without any, but the generated documentation could perhaps use some.
>
> Perhaps:
>
> Specifies a string value or the explicit lack of a string (often used as
> an optional parameter type, where omitting the parameter has different
> semantics than supplying null).
> @s a JSON string
> @n an explicit NULL
>
>
> and certainly worth having
>
> Since: 2.10

What about:

##
# @StrOrNull:
#
# This is a string value or the explicit lack of a string (null
# pointer in C).  Intended for cases when 'optional absent' already
# has a different meaning.
#
# @s: the string value
# @n: no string value
#
# Since: 2.10
##