Re: Notes on Generating Python signatures for QMP RPCs

[John Snow]

On Thu, Feb 3, 2022 at 5:04 AM Markus Armbruster <armbru@redhat.com> wrote:
> John Snow <jsnow@redhat.com> writes:
> > On Thu, Jan 27, 2022 at 9:03 AM Markus Armbruster <armbru@redhat.com> wrote:
> >> John Snow <jsnow@redhat.com> writes:

> >> > (7) I have no idea what to do about functions that "may not return".
> >> > The QGA stuff in particular, I believe, is prone to some weirdness
> >> > that violates the core principles of the QMP spec.
> >>
> >> Yes.
> >>
> >> docs/interop/qmp-spec.txt dictates a command sends either a success or
> >> an error response.  Makes sense.
> >>
> >> QGA has a few commands that shut down the guest.  How could such a
> >> command send a success response?  If it sends it before it initiates
> >> shutdown, response transmission races with shutdown.  The easy way out
> >> is violating qmp-spec.txt.  Thus, 'success-response': false.  Just for
> >> QGA.
> >>
> >
> > Oh, whoops, I already have the information we need. O:-)
> > (Assuming that 'success-response' is visible in the introspection data, 
> > anyway.
>
> qapi/introspect.json:
>
>     ##
>     # @SchemaInfoCommand:
>     [...]
>     # TODO: @success-response (currently irrelevant, because it's QGA, not 
> QMP)
>     #
>     # Since: 2.5
>     ##
>     { 'struct': 'SchemaInfoCommand',
>       'data': { 'arg-type': 'str', 'ret-type': 'str',
>                 '*allow-oob': 'bool' } }
>
> The TODO neglects to spell out "and QGA doesn't support introspection so
> far".
>

Oof, ouch, my bones.

What will it take to add introspection to QGA? (Is this GSoC/Outreachy
appropriate?)
(This is not critically important to me, just a backburner thought.)

--js