Re: [Qemu-devel] [PATCH 04/13] qemu-img: Suppress unhelpful extra errors in convert, resize

[John Snow <jsnow@redhat.com>]

On 02/16/2015 09:44 AM, Markus Armbruster wrote:
> add_old_style_options() for img_convert() and img_resize() use
> qemu_opt_set(), which reports errors with qerror_report_err().  Its
> error messages aren't helpful here, the caller reports one that
> actually makes sense.  Reproducer:
>
>      $ qemu-img convert -B raw in.img out.img
>      qemu-img: Invalid parameter 'backing_file'
>      qemu-img: Backing file not supported for file format 'raw'
>
> Switch to qemu_opt_set_err() to get rid of the unwanted messages.
>
> Signed-off-by: Markus Armbruster <armbru@redhat.com>
> ---
>   qemu-img.c | 16 ++++++++++++----
>   1 file changed, 12 insertions(+), 4 deletions(-)
>
> diff --git a/qemu-img.c b/qemu-img.c
> index 7eea84a..7a806bc 100644
> --- a/qemu-img.c
> +++ b/qemu-img.c
> @@ -338,17 +338,23 @@ static int add_old_style_options(const char *fmt, QemuOpts *opts,
>                                    const char *base_filename,
>                                    const char *base_fmt)
>   {
> +    Error *err = NULL;
> +
>       if (base_filename) {
> -        if (qemu_opt_set(opts, BLOCK_OPT_BACKING_FILE, base_filename)) {
> +        qemu_opt_set_err(opts, BLOCK_OPT_BACKING_FILE, base_filename, &err);
> +        if (err) {
>               error_report("Backing file not supported for file format '%s'",
>                            fmt);
> +            error_free(err);
>               return -1;
>           }
>       }
>       if (base_fmt) {
> -        if (qemu_opt_set(opts, BLOCK_OPT_BACKING_FMT, base_fmt)) {
> +        qemu_opt_set_err(opts, BLOCK_OPT_BACKING_FMT, base_fmt, &err);
> +        if (err) {
>               error_report("Backing file format not supported for file "
>                            "format '%s'", fmt);
> +            error_free(err);
>               return -1;
>           }
>       }
> @@ -2758,6 +2764,7 @@ out:
>
>   static int img_resize(int argc, char **argv)
>   {
> +    Error *err = NULL;
>       int c, ret, relative;
>       const char *filename, *fmt, *size;
>       int64_t n, total_size;
> @@ -2830,8 +2837,9 @@ static int img_resize(int argc, char **argv)
>
>       /* Parse size */
>       param = qemu_opts_create(&resize_options, NULL, 0, &error_abort);
> -    if (qemu_opt_set(param, BLOCK_OPT_SIZE, size)) {
> -        /* Error message already printed when size parsing fails */
> +    qemu_opt_set_err(param, BLOCK_OPT_SIZE, size, &err);
> +    if (err) {
> +        error_report_err(err);

Creates a new warning/failure for me, if basing off of origin/master or 
kevin/block:

   CC    qemu-img.o
/home/bos/jhuston/src/qemu/qemu-img.c: In function ‘img_resize’:
/home/bos/jhuston/src/qemu/qemu-img.c:2844:9: error: implicit 
declaration of function ‘error_report_err’ 
[-Werror=implicit-function-declaration]
          error_report_err(err);
          ^
/home/bos/jhuston/src/qemu/qemu-img.c:2844:9: error: nested extern 
declaration of ‘error_report_err’ [-Werror=nested-externs]
cc1: all warnings being treated as errors
make: *** [qemu-img.o] Error 1
make: *** Waiting for unfinished jobs....


>           ret = -1;
>           qemu_opts_del(param);
>           goto out;
>