$0 (or argv[0]) not used in error messages in zsh -c inlinescripts

$0 (or argv[0]) not used in error messages in zsh -c inlinescripts

[Stephane Chazelas]

(minor)

$ zsh -uc 'echo $0; :>/; 0=foo; $1' myinlinescript
myinlinescript
zsh:1: is a directory: /
zsh:1: 1: parameter not set

I expected:

myinlinescript
myinlinescript:1: is a directory: /
foo:1: 1: parameter not set

Like most other Bourne-like shells (except yash) do (except for the assignment
to $0 which none other supports).

Isn't it the whole point of being able to specify $0, so it's
treated as the script's name when using zsh -c?

Note that the interpreter's argv[0] is always ignored in any case.

$ ARGV0=foo zsh -uc 'echo $0; :>/; $1'
foo
zsh:1: is a directory: /
zsh:1: 1: parameter not set

Also applies to:

$ ARGV0=foo zsh -u <<< 'echo $0; :>/; 0=bar; $1'
foo
zsh: is a directory: /
zsh: 1: parameter not set

Modifications to $0 are honoured in:

$ zsh <(<<<'echo "$0"; :>/; 0=foo; :>/')
/proc/self/fd/11
/proc/self/fd/11:1: is a directory: /
foo:1: is a directory: /

Not in:

$ zsh -c '. $1' foobar =(<<<'echo $0; :>/; 0=foo; :>/')
/tmp/zshl53EOM
/tmp/zshl53EOM:1: is a directory: /
/tmp/zshl53EOM:1: is a directory: /


See also:

$ zsh -c 'f() { echo $0; :>/; 0=foo; :>/; }; f'
f
f: is a directory: /
f: is a directory: /


(modified $0 not used in error message).

-- 
Stephane

Re: $0 (or argv[0]) not used in error messages in zsh -c inlinescripts

[Bart Schaefer]

I believe that comes down to this bit of code in zwarning() (utils.c):

    char *prefix = scriptname ? scriptname : (argzero ? argzero : "");
...
        /*
         * scriptname is set when sourcing scripts, so that we get the
         * correct name instead of the generic name of whatever
         * program/script is running.  It's also set in shell functions,
         * so test locallevel, too.
         */
        nicezputs((isset(SHINSTDIN) && !locallevel) ? "zsh" : prefix, stderr);

In parseopts() (init.c) for the -c option there is:

                if (toplevel)
                    scriptname = scriptfilename = ztrdup("zsh");

So because scriptname is always preferred and at toplevel is always
set, you get the observed behavior.

This is all pretty tangled up with POSIX_ARGZERO as well, so I'm not
certain of the correct fix.