Re: Exit value of command glob qualifier within for loop

["Benjamin R. Haskell" <zsh@benizi.com>]

On Sun, 27 Jun 2010, Joke de Buhr wrote:

> Hi,
> 
> I'm using a for loop with glob qualifiers to process a list of altered 
> files. It looks like this:
> 
>     for a in *(e:age today:); do some_command $a ; done
> 
> 
> The problem, I've enabled the option PRINT_EXIT_VALUE. Now zsh echoes 
> the line "zsh: exit 1"  for every file which doesn't match the 
> qualifier.
> 
> If I use this (builtin) command zsh reports the exit status as well:
>     print *(e:age today:)
> 
> But if I use this (external) command zsh doesn't:
>     ls *(e:age today:)
> 
> 
> I'm not sure if this behavior is intentional but it sure is annoying.  
> Disabling PRINT_EXIT_VALUE before running these commands doesn't make 
> that much fun. I think zsh shouldn't print the exit value at all.

Maybe not the answer you're hoping for, but with very recent zsh[1], the 
following pair of commands can provide an effect similar to 
PRINT_EXIT_VALUE while specifically excluding a non-zero return status 
when inside a glob qualifier:

# $1 $2 and $3 are possibly-different versions of the command
# $1 seemed fine to me
preexec () { _debug_lastcmd=$1 }

# Print "(command): exit (status)" to stderr,
# unless context contains globqual
TRAPZERR () {
	local ret=$?
	if (( ! $zsh_eval_context[(Ie)globqual] )) ; then
		printf "%s: exit %d\n" $_debug_lastcmd $? >&2
	fi
}

NB. I never use PRINT_EXIT_VALUE, nor do I plan to, so I'm not sure what 
behaviors might be different, behavior-wise.  I suspect that 
PRINT_EXIT_VALUE is finer-grained in its output, for starters.

-- 
Best,
Ben

[1] Anything past git commit 09960dc (master~39 as of right now), which 
is where Peter included his zsh_eval_context patch discussed in:
zsh-workers 27951: http://www.zsh.org/mla/workers/2010/msg00403.html