Le 18/11/2009 09:34, David Korn a écrit :
cc: [email protected]
Subject: Re: [ast-developers] Set -o nounset fails when expanding "$@"
--------
That bug was fixed in ksh93t+. It is listed in the RELEASE file as a bug
fix on 09-05-12.
09-05-12 To conform with POSIX, the -u option only checks for unset variables
and subscript elements rather than checking for all parameters.
Hi,
I'm rereading the -developers ml archive, and this change looks wrong to me.
IMHO, "$@" should effectivelly not fail w/ no arg and set -u is set, but
$1 should fail w/ no arg.
in other words, it is important to exit on $1 if unset to make the
distinction on required and optional parameter.
the only reference I found in SUSv4 is :
http://pubs.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#tag_18_25
which says :
*-u*
The shell shall write a message to standard error when it tries to
expand a variable that is not set and immediately exit. An
interactive shell shall not exit.
unfortunatelly, I found no rationale nor other reference.
ex. :
set -u
foo () {
echo "$@"
x=$1 y=${2-}
echo $x:$y
}
foo 1
=> ok
foo
=> should not fail on "$@" which is allowed to be nothing,
but should fail on $1 which is not set but a required parameter,
should not fail on $2 which is an optional parameter.
ksh88 historically fails on "$@"
(d)ash, bash, mksh and zsh do it this way
posh and ksh93 fail nowhere
Regards,
Cyrille Lefevre
--
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