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Date: Mon, 29 Jul 2013 17:05:23 -0400
From: Luiz Capitulino <lcapitulino@redhat.com>
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Subject: Re: [Qemu-devel] [PATCH] migration: don't use uninitialized
 variables
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To: Eric Blake <eblake@redhat.com>
Cc: Pawit Pornkitprasan <p.pawit@gmail.com>, qemu-devel@nongnu.org, Ryousei Takano <takano-ryousei@aist.go.jp>, Juan Quintela <quintela@redhat.com>

On Fri, 19 Jul 2013 04:57:51 -0600
Eric Blake <eblake@redhat.com> wrote:

> On 07/18/2013 08:36 PM, Pawit Pornkitprasan wrote:
> > The qmp_migrate method uses the 'blk' and 'inc' parameter without
> > checking if they're valid or not (they may be uninitialized if
> > command is received via QMP)
> > 
> > Signed-off-by: Pawit Pornkitprasan <p.pawit@gmail.com>
> > ---
> >  migration.c | 4 ++--
> >  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> Reviewed-by: Eric Blake <eblake@redhat.com>
> 
> However, wouldn't it be nice if we improved the qapi generator to
> guarantee a sane default value for optional parameters, even when
> has_value is false?

We could do that for bool and pointers, but this wouldn't help
integers and enums. Also, even if we had default values, I guess
I'd enforce a common idiom for handling optionals as this is also
a good practice for preventing bugs.