Re: [Qemu-devel] [PATCH v16 02/24] qapi: Guarantee NULL obj on input visitor callback error

[Eric Blake <eblake@redhat.com>]

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On 04/29/2016 06:10 AM, Eric Blake wrote:
> On 04/29/2016 02:28 AM, Markus Armbruster wrote:
>> Eric Blake <eblake@redhat.com> writes:
>>
>>> Our existing input visitors were not very consistent on errors
>>> in a function taking 'TYPE **obj' (that is, start_struct(),
>>> start_alternate(), type_str(), and type_any(). next_list() is
>>> similar, except that since commit 08f9541, it can't fail).
>>
>> Multiple sentences in a parenthesis, ugh :)
>>
>>     Our existing input visitors were not very consistent on errors in a
>>     function taking 'TYPE **obj'.  These are start_struct(),
>>     start_alternate(), type_str(), and type_any().  next_list() is
>>     similar, but can't fail (see commit since 08f9541).
>>
>> Can touch up on commit.
>>
> 
> Yes, sounds better.

Spoke too soon: "see commit since 08f9541" is too wordy, should be
either "see commit 08f9541" or "since commit 08f9541"

> 
> 
>>> @@ -51,10 +57,16 @@ void visit_start_alternate(Visitor *v, const char *name,
>>>                             GenericAlternate **obj, size_t size,
>>>                             bool promote_int, Error **errp)
>>>  {
>>> +    Error *err = NULL;
>>> +
>>>      assert(obj && size >= sizeof(GenericAlternate));
>>>      if (v->start_alternate) {
>>> -        v->start_alternate(v, name, obj, size, promote_int, errp);
>>> +        v->start_alternate(v, name, obj, size, promote_int, &err);
>>>      }
>>> +    if (v->type == VISITOR_INPUT) {
>>> +        assert(!err != !*obj);
>>
>> Could assert(v->start_alternate && !err != !*obj), to preempt "what if
>> !v->start_alternate" worries.  If you like that, I can do it on commit.
> 
> Can't hurt :)
> 

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


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