Re: [Qemu-devel] [PATCH v2 1/2 for-2.12?] qapi: Parameter gl of DisplayType now accept an enum

[Eric Blake]

On 04/12/2018 09:11 AM, Elie Tournier wrote:
> Hello,
> 
> On Tue, Apr 10, 2018 at 03:33:35PM +0200, Gerd Hoffmann wrote:
>>> # @off: Disable OpenGL (default).
> 
> Just to be sure, I have to add @ in front of all parameter, right?

Yes.


>>> You may be in luck - there is no instance of 'window-close' in the
>>> introspection output, which means 'DisplayType' exists only for ease of
>>> command-line parsing and is not currently used by QMP, so tweaks here
>>> are not affecting the command line.
>>
>> Yes, right now the struct is only used to store the parsed command line
>> opts, so no effect on QMP.
>>
>> Plan for the future is to also parse command line options with generic
>> qapi/json code instead of the home-grown parser, but that switch didn't
>> happen yet.
>>
>>> That said, you can STILL name the enum value something smarter than 'on'
>>> IF you make the change now, for 2.12, given that the QAPI type was only
>>> introduced in 2.12 (you only have to worry about backwards compatibility
>>> if 2.11 already parsed gl=on).
>>
>> gl=on is older, so that must continue to work.  Making both "on" and
>> "auto" work isn't a problem for our home-grown parser (aka
>> parse_display() in vl.c).  But having quirks like this makes the switch
>> to generic parser code more difficuilt, so I'd prefer to avoid that ...
> 
> Is it possible to upstream this change before 2.12 release?

At this point, no, we've missed -rc3, and it's not a big enough bug to
warrant needing -rc4 on its own.  And as Gerd said, we already parsed
'gl=on' in 2.11 (the QAPI representation is new to 2.12, but only to
simplify how the existing command line parser was coded), so that's
different than if 2.12 were introducing brand-new content in a form that
should be fixed before it is baked into existing uses.

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3266
Virtualization:  qemu.org | libvirt.org

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