[DTrace-devel] [PATCH 19/20] test: allow test options to be set to "-e"

[Kris Van Hees]

On Wed, May 11, 2022 at 10:13:01PM +0100, Nick Alcock via DTrace-devel wrote:
> The curse of echo caught us again.  Using printf keeps the -e, but even
> then we have to doble-quote the argument because one layer of quotes
> will be eaten by the eval, and printf with more args than format string
> args reuses the format string over and over again: if it's %s, this
> effectively squashes the args together with intervening spaces removed.
> 
> Signed-off-by: Nick Alcock <nick.alcock at oracle.com>

Reviewed-by: Kris Van Hees <kris.van.hees at oracle.com>

... but it really should have had a test
    I will add one (in the interest of time)

... and queued for dev, 

> ---
>  runtest.sh | 11 +++++++----
>  1 file changed, 7 insertions(+), 4 deletions(-)
> 
> diff --git a/runtest.sh b/runtest.sh
> index 387907a8df4a..c9a23ba0ad08 100755
> --- a/runtest.sh
> +++ b/runtest.sh
> @@ -177,14 +177,17 @@ extract_options()
>  
>              _pid='$_pid'
>  
> -            # This trick is because printf squashes out spaces, echo -e -e foo
> -            # prints 'foo', and echo -e -- "foo" prints "-- foo".
> +            # This trick is because printf with a straight eval ends up called
> +            # with more args than format string items and squashes out spaces,
> +            # echo -e -e foo prints 'foo', and bash's builtin echo -e -- "foo"
> +            # prints "-- foo".  coreutils echo does the right thing, but is more
> +            # expensive than the builtin printf, so use it only when needed.
>  
>              if [[ -n $val ]]; then
>                  if [[ -n $expand ]]; then
> -                    eval echo ''"$val"
> +                    eval printf "%s" \""$val"\"
>                  else
> -                    echo ''"$val"
> +                    printf "%s" ''"$val"
>                  fi
>              fi
>              return
> -- 
> 2.36.1.263.g194b774378.dirty
> 
> 
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