Re: [PATCH] configure: silence 'shift' error message in version_ge()

[Peter Maydell]

On Fri, 21 Aug 2020 at 16:00, Stefano Garzarella <sgarzare@redhat.com> wrote:
>
> If there are less than 2 arguments in version_ge(), the second shift
> prints this error:
>     ../configure: line 232: shift: shift count out of range
>
> Let's shut it up, since we're expecting this situation.
>
> Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
> ---
>  configure | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/configure b/configure
> index 4e5fe33211..de4bd0df36 100755
> --- a/configure
> +++ b/configure
> @@ -229,7 +229,7 @@ version_ge () {
>          set x $local_ver1
>          local_first=${2-0}
>          # shift 2 does nothing if there are less than 2 arguments
> -        shift; shift
> +        shift; shift 2>/dev/null

POSIX says
https://pubs.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#shift

"If the n operand is invalid or is greater than "$#", this may be
considered a syntax error and a non-interactive shell may exit"

so I think that we need to actually avoid the excess shift,
not just suppress any warning it might print. (I'm not sure
Philippe's "shift || shift" patch can work for that, though,
as the exit status doesn't distinguish "valid shift but don't
do it again" from "valid shift and more args to come".)

thanks
-- PMM