[Libguestfs] [nbdkit PATCH] maint: Improve ./nbdkit handling of --opt=value

[Richard W.M. Jones]

On Tue, Jan 23, 2018 at 09:58:27PM -0600, Eric Blake wrote:
> Although useful for in-tree debugging, the ./nbdkit script was not
> very nice when it comes to using the '--longopt=value' single-string
> form of options, compared to the two-string '--longopt value' form.
> Since we used a glob for the multiple spellings of --exportname and
> --pidfile, the script would try to treat the next argument literally
> instead of recognizing that the argument was already consumed.
> Likewise, the script was not recognizing '--filter=foo'.

Right, this is the reason why all the tests use ‘--filter foo’, which
is annoying and awkward.

> Since the script already relies on bash, we can exploit bash's
> case fallthrough (using ';&' instead of ';;'), to rewrite inline
> --filter=foo without having to duplicate logic.

Nice, I learn a new thing every day ...

> This does NOT try to honor option abbreviations.  If you are testing
> that aspect of getopt_long, don't use this script ;)
> 
> Signed-off-by: Eric Blake <eblake at redhat.com>
> ---
> 
> I'm pushing this one now, as it tripped me up during testing.
> 
>  nbdkit.in | 10 ++++++++++
>  1 file changed, 10 insertions(+)
> 
> diff --git a/nbdkit.in b/nbdkit.in
> index d1caf57..996616d 100644
> --- a/nbdkit.in
> +++ b/nbdkit.in
> @@ -65,6 +65,11 @@ verbose=
>  while [ $# -gt 0 ]; do
>      case "$1" in
>          # Flags that take an argument.  We must not rewrite the argument.
> +	# But make sure globs don't mishandle longopts with =.
> +	--export*=* | --pid*=*)
> +	    args[$i]="$1"
> +	    shift
> +	    ;;
>          -e | --export* | -g | --group | -i | --ip* | -P | --pid* | -p | --port | --run | --selinux-label | -t | --threads | --tls | --tls-certificates | -U | --unix | -u | --user)
>              args[$i]="$1"
>              ((++i))
> @@ -80,6 +85,11 @@ while [ $# -gt 0 ]; do
>              ;;
> 
>          # Filters can be rewritten if purely alphanumeric.
> +	--filter=*)
> +	    tmp=${1#*=}
> +	    shift
> +	    set - --filter "$tmp" "$@"
> +	    ;& # fallthru
>          --filter)
>              args[$i]="--filter"
>              ((++i))

Yup, this is great, ACK.

You might also want to adjust the tests to use ‘--filter=foo’ (no need
to review that change).

Rich.

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