From mboxrd@z Thu Jan  1 00:00:00 1970
Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43)
	id 1My5CG-0000sp-Nr
	for qemu-devel@nongnu.org; Wed, 14 Oct 2009 10:51:25 -0400
Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43)
	id 1My5CB-0000pa-25
	for qemu-devel@nongnu.org; Wed, 14 Oct 2009 10:51:23 -0400
Received: from [199.232.76.173] (port=39044 helo=monty-python.gnu.org)
	by lists.gnu.org with esmtp (Exim 4.43) id 1My5C9-0000pL-MK
	for qemu-devel@nongnu.org; Wed, 14 Oct 2009 10:51:18 -0400
Received: from mx1.redhat.com ([209.132.183.28]:33132)
	by monty-python.gnu.org with esmtp (Exim 4.60)
	(envelope-from <lcapitulino@redhat.com>) id 1My5C8-00064n-It
	for qemu-devel@nongnu.org; Wed, 14 Oct 2009 10:51:17 -0400
Date: Wed, 14 Oct 2009 11:51:07 -0300
From: Luiz Capitulino <lcapitulino@redhat.com>
Subject: Re: [Qemu-devel] [PATCH 7/9] qdev: Use QError for not found error
Message-ID: <20091014115107.381fb26c@doriath>
In-Reply-To: <877huy6hzm.fsf@pike.pond.sub.org>
References: <1255453026-18637-1-git-send-email-lcapitulino@redhat.com>
	<1255453026-18637-8-git-send-email-lcapitulino@redhat.com>
	<877huy6hzm.fsf@pike.pond.sub.org>
Mime-Version: 1.0
Content-Type: text/plain; charset=US-ASCII
Content-Transfer-Encoding: 7bit
List-Id: qemu-devel.nongnu.org
List-Unsubscribe: <http://lists.nongnu.org/mailman/listinfo/qemu-devel>,
	<mailto:qemu-devel-request@nongnu.org?subject=unsubscribe>
List-Archive: <http://lists.gnu.org/pipermail/qemu-devel>
List-Post: <mailto:qemu-devel@nongnu.org>
List-Help: <mailto:qemu-devel-request@nongnu.org?subject=help>
List-Subscribe: <http://lists.nongnu.org/mailman/listinfo/qemu-devel>,
	<mailto:qemu-devel-request@nongnu.org?subject=subscribe>
To: Markus Armbruster <armbru@redhat.com>
Cc: aliguori@us.ibm.com, qemu-devel@nongnu.org, kraxel@redhat.com

On Wed, 14 Oct 2009 00:34:21 +0200
Markus Armbruster <armbru@redhat.com> wrote:

> Luiz Capitulino <lcapitulino@redhat.com> writes:
> 
> > Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
> > ---
> >  hw/qdev.c |    4 ++--
> >  1 files changed, 2 insertions(+), 2 deletions(-)
> >
> > diff --git a/hw/qdev.c b/hw/qdev.c
> > index 906e897..3ce48f7 100644
> > --- a/hw/qdev.c
> > +++ b/hw/qdev.c
> > @@ -28,6 +28,7 @@
> >  #include "net.h"
> >  #include "qdev.h"
> >  #include "sysemu.h"
> > +#include "qerror.h"
> >  #include "monitor.h"
> >  
> >  static int qdev_hotplug = 0;
> > @@ -176,8 +177,7 @@ DeviceState *qdev_device_add(QemuOpts *opts)
> >      /* find driver */
> >      info = qdev_find_info(NULL, driver);
> >      if (!info) {
> > -        qemu_error("Device \"%s\" not found.  Try -device '?' for a list.\n",
> > -                   driver);
> > +        qemu_error_structed(QERR_QDEV_NFOUND, "{ s: s }", "name", driver);
> >          return NULL;
> >      }
> >      if (info->no_user) {
> 
> And here we pay the price for structured error objects: reporting an
> error becomes more difficult.  The harder you make reporting errors, the
> fewer errors get caught and reported.  Also, the result is harder to
> read.
> 
> If we need the structure, then it's just a price we have to pay.  Do we
> need it?

 Yes, if we want clients to able to determine error causes.

 Of course that we can decide to provide less information, but this
structure has three users (monitor protocol, command-line and monitor),
so adding information for one of them means adding for them all.