Re: [Qemu-devel] [PATCH for-1.5] qmp: add query-drive-mirror-capabilities

[Markus Armbruster]

Luiz Capitulino <address@hidden> writes:

> On Fri, 26 Apr 2013 15:40:25 +0200
> Markus Armbruster <address@hidden> wrote:
>
>> Paolo Bonzini <address@hidden> writes:
>> 
>> > Il 25/04/2013 14:26, Luiz Capitulino ha scritto:
>> >> That's a good point, although I wonder if a command could have a new
>> >> capability that's not mapped to a new argument. IOW, I'd expect most/all
>> >> new capabilities to always be mapped to new arguments.
>> >
>> > A new enum value would also be a new capability, but it's handled better
>> > by enabling introspection of enum values.
>> 
>> An extension that adds neither arguments nor argument values is probably
>> an incompatible change, not a proper extension.  Don't do that then.
>
> I think Paolo is referring to a command that takes an enumeration as
> an argument, eg. transaction.

Extending the enumeration adds argument values, i.e. it's just fine.