Re: [Qemu-devel] [PATCH 2/3] qapi: clear given pointer

["Daniel P. Berrange" <berrange@redhat.com>]

On Wed, Sep 21, 2016 at 02:36:28PM +0400, Marc-André Lureau wrote:
> Some getters already set *obj argument to NULL early, let's do this for
> all for consistent behaviour in case of errors.
> 
> Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>

If we want consistent behaviour, there's plenty more visit methods
that need updating beyond these two.  eg input_type_int64 will
leave '*obj' untouched on error.

In fact if we want to have '*obj' given a NULL value on error,
then it seems we should instead add code to 'qapi-visit-core.c'
to always initialize '*obj' to NULL, instead of doing it in
qmp-input-visitor.c That way all visitor implementations get
the same behaviour

Alternatively, we could say that '*obj' should never be touched
on error paths, in which case we've a bunchof cleanup todo
in qmp_input_visitor to avoid splattering *obj.

Regards,
Daniel
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