From mboxrd@z Thu Jan  1 00:00:00 1970
Received: from eggs.gnu.org ([2001:4830:134:3::10]:57055)
	by lists.gnu.org with esmtp (Exim 4.71)
	(envelope-from <berrange@redhat.com>) id 1bmiir-0001sk-V1
	for qemu-devel@nongnu.org; Wed, 21 Sep 2016 10:42:07 -0400
Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71)
	(envelope-from <berrange@redhat.com>) id 1bmiio-0003YY-Oq
	for qemu-devel@nongnu.org; Wed, 21 Sep 2016 10:42:05 -0400
Received: from mx1.redhat.com ([209.132.183.28]:54112)
	by eggs.gnu.org with esmtp (Exim 4.71)
	(envelope-from <berrange@redhat.com>) id 1bmiio-0003YO-JX
	for qemu-devel@nongnu.org; Wed, 21 Sep 2016 10:42:02 -0400
Date: Wed, 21 Sep 2016 15:41:58 +0100
From: "Daniel P. Berrange" <berrange@redhat.com>
Message-ID: <20160921144158.GT15535@redhat.com>
Reply-To: "Daniel P. Berrange" <berrange@redhat.com>
References: <20160921103629.6410-1-marcandre.lureau@redhat.com>
	<20160921103629.6410-3-marcandre.lureau@redhat.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=utf-8
Content-Disposition: inline
In-Reply-To: <20160921103629.6410-3-marcandre.lureau@redhat.com>
Content-Transfer-Encoding: quoted-printable
Subject: Re: [Qemu-devel] [PATCH 2/3] qapi: clear given pointer
List-Id: <qemu-devel.nongnu.org>
List-Unsubscribe: <https://lists.nongnu.org/mailman/options/qemu-devel>,
	<mailto:qemu-devel-request@nongnu.org?subject=unsubscribe>
List-Archive: <http://lists.nongnu.org/archive/html/qemu-devel/>
List-Post: <mailto:qemu-devel@nongnu.org>
List-Help: <mailto:qemu-devel-request@nongnu.org?subject=help>
List-Subscribe: <https://lists.nongnu.org/mailman/listinfo/qemu-devel>,
	<mailto:qemu-devel-request@nongnu.org?subject=subscribe>
To: =?utf-8?Q?Marc-Andr=C3=A9?= Lureau <marcandre.lureau@redhat.com>
Cc: qemu-devel@nongnu.org, berto@igalia.com, armbru@redhat.com

On Wed, Sep 21, 2016 at 02:36:28PM +0400, Marc-Andr=C3=A9 Lureau wrote:
> Some getters already set *obj argument to NULL early, let's do this for
> all for consistent behaviour in case of errors.
>=20
> Signed-off-by: Marc-Andr=C3=A9 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
--=20
|: http://berrange.com      -o-    http://www.flickr.com/photos/dberrange=
/ :|
|: http://libvirt.org              -o-             http://virt-manager.or=
g :|
|: http://autobuild.org       -o-         http://search.cpan.org/~danberr=
/ :|
|: http://entangle-photo.org       -o-       http://live.gnome.org/gtk-vn=
c :|