On Thu, 18 Apr 2013 15:09:27 +0200
Pavel Hrdina <phrd...@redhat.com> wrote:
> On 18.4.2013 14:59, Kevin Wolf wrote:
> > Am 18.04.2013 um 13:52 hat Pavel Hrdina geschrieben:
> >> On 18.4.2013 13:44, Kevin Wolf wrote:
> >>> Am 16.04.2013 um 18:05 hat Pavel Hrdina geschrieben:
> >>>> Later in the patch series we will use this function few times.
> >>>> This will avoid of duplicating the code.
> >>>>
> >>>> Signed-off-by: Pavel Hrdina <phrd...@redhat.com>
> >>>> ---
> >>>> qemu-img.c | 17 +++++++++++------
> >>>> 1 file changed, 11 insertions(+), 6 deletions(-)
> >>>>
> >>>> diff --git a/qemu-img.c b/qemu-img.c
> >>>> index 31627b0..dbacdb7 100644
> >>>> --- a/qemu-img.c
> >>>> +++ b/qemu-img.c
> >>>> @@ -322,6 +322,16 @@ static int add_old_style_options(const char *fmt,
> >>>> QEMUOptionParameter *list,
> >>>> return 0;
> >>>> }
> >>>>
> >>>> +static int qemu_img_handle_error(const char *msg, Error *err)
> >>>> +{
> >>>> + if (error_is_set(&err)) {
> >>>> + error_report("%s: %s", msg, error_get_pretty(err));
> >>>> + error_free(err);
> >>>> + return 1;
> >>>> + }
> >>>> + return 0;
> >>>> +}
> >>>> +
> >>>> static int img_create(int argc, char **argv)
> >>>> {
> >>>> int c;
> >>>> @@ -400,13 +410,8 @@ static int img_create(int argc, char **argv)
> >>>>
> >>>> bdrv_img_create(filename, fmt, base_filename, base_fmt,
> >>>> options, img_size, BDRV_O_FLAGS, &local_err,
> >>>> quiet);
> >>>> - if (error_is_set(&local_err)) {
> >>>> - error_report("%s", error_get_pretty(local_err));
> >>>> - error_free(local_err);
> >>>> - return 1;
> >>>> - }
> >>>>
> >>>> - return 0;
> >>>> + return qemu_img_handle_error("qemu-img create failed", local_err);
> >>>> }
> >>>
> >>> This makes a change to the error message that isn't mentioned in the
> >>> commit message. It should definitely be mentioned there, but I'm not
> >>> even sure if it's a good change. Today you get something like:
> >>>
> >>> $ qemu-img create -f foo test.img
> >>> qemu-img: Unknown file format 'foo'
> >>>
> >>> With the patch applied it becomes:
> >>>
> >>> $ qemu-img create -f foo test.img
> >>> qemu-img: qemu-img create failed: Unknown file format 'foo'
> >>>
> >>> Does this add any useful information or does it just make the error
> >>> message longer? I feel it's the latter.
> >>>
> >>> Kevin
> >>>
> >>
> >> Thanks for pointing this out, it should be
> >> qemu_img_handle_error("create failed", local_err);
> >>
> >> and later in patch series also
> >> qemu_img_handle_error("snapshot create failed", local_err);
> >>
> >> Is that OK after this change?
> >
> > I would in fact leave the error message as it is today. The "create
> > failed" doesn't help me understand the error better. I already know that
> > it's a create command that failed, because it was me who called 'qemu-img
> > create'.
> >
> > Kevin
> >
>
> Yes that's true and make sense, but what if another tool internally uses
> the qemu-img command? I know that the tool could print/return/whatever
> proper error message, but qemu-img could help with that printing more
> information.
Then the tool should prepend any relevant information. We can't guess
all use cases.
