Re: [PATCH v2 2/6] migration: Updated QAPI format for 'migrate' qemu monitor command

[Markus Armbruster]

Daniel P. Berrangé <berrange@redhat.com> writes:

> On Wed, Feb 08, 2023 at 02:17:12PM -0600, Eric Blake wrote:

[...]

>> I'm guessing the reason you didn't go with 'socket': 'SocketAddress'
>> is that SocketAddress is itself a discriminated union, and Markus does
>> not yet have the QAPI generator wired up to support one union as a
>> branch of another larger union?  It leads to extra nesting on the wire
>> [2]
>
> I don't know the backstory on this limitation. Is it something that
> is very difficult to resolve ? I think it is highly desirable to have
> 'socket': 'SocketAddress' here. It would be a shame to introduce this
> better migration API design and then have it complicated by a possibly
> short term limitation of QAPI.

We evolve the QAPI language to satisfy concrete use cases.  If you could
use a language improvement, make a case for it, and we'll see what we
can do within a time frame that works for you.  Better than ugly
work-arounds on the silent assumption the language cannot be adapted.