Re: [Qemu-devel] [PATCH 4/9] qmp: Clean up qmp_query_spice() #ifndef !CONFIG_SPICE dummy

[Eric Blake <eblake@redhat.com>]

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On 01/13/2015 10:50 AM, Markus Armbruster wrote:
> QMP command query-spice exists only #ifdef CONFIG_SPICE.  Due to QAPI
> limitations, we need a dummy function anyway, but it's unreachable.
> 
> Our current dummy function goes out of its way to produce the exact
> same error as the QMP core does for unknown commands.  Cute, but both
> unclean and unnecessary.  Replace by straight abort().
> 
> Signed-off-by: Markus Armbruster <armbru@redhat.com>
> ---

> + * qmp-commands.hx ensures that QMP command query-spice exists only
> + * #ifdef CONFIG_SPICE.  Necessary for an accurate query-commands
> + * result.  However, the QAPI schema is blissfully unaware of that,
> + * and the QAPI code generator happily generates a dead
> + * qmp_marshal_input_query_spice() that calls qmp_query_spice().
> + * Provide it one, or else linking fails.
> + * FIXME Educate the QAPI schema on CONFIG_SPICE.

There's probably several commands that are only conditionally compiled
in qmp-commands.hx, but where the qapi has no way to express that they
are conditional on how the binary was compiled.  I'm not sure if it
would help the user to document that a command listed in the .json might
not actually exist, but if enhancing the qapi code generator to
understand conditionals made for less maintenance, then that alone would
be worth cleaning up this FIXME.

In the meantime, your patch is just fine.

Reviewed-by: Eric Blake <eblake@redhat.com>

-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org


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