Re: [Qemu-devel] [PATCH v15 02/23] qapi: Guarantee NULL obj on input visitor callback error

[Eric Blake]

On 04/28/2016 07:00 AM, Eric Blake wrote:
>> The commit message lists start_struct(), start_alternate(), next_list(),
>> type_str(), and type_any().  You cover them except for next_list().  Why
>> is that missing?
> 
> Because *obj can be NULL after next_list() if the list is empty.  But
> there may still be a weaker assertion worth having: if err, then *obj
> must be NULL; and if *obj, then err must not be set (weaker in that for
> all the other functions touched, exactly one of the two conditions can
> result, but here, !err and !*obj is valid as a third condition).

Actually, because visit_next_list() can't fail (we removed the errp
argument earlier).  When we finally move the list head allocation into
visit_start_list later in the series (22/23), then we should add the
(weaker) assert there.

> 
> Depending on what else you find later in the series, I may just post a
> fixup for this patch.

Still my plan.

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

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