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Re: [SOLVED] Libtool/zsh quoting problem: a zsh... bug?
- X-seq: zsh-workers 22238
- From: Andrey Borzenkov <arvidjaar@xxxxxxxxxx>
- To: zsh-workers@xxxxxxxxxx
- Subject: Re: [SOLVED] Libtool/zsh quoting problem: a zsh... bug?
- Date: Sun, 12 Feb 2006 10:46:06 +0300
- In-reply-to: <20060211181440.GA30984@xxxxxxxxxxxxx>
- Mailing-list: contact zsh-workers-help@xxxxxxxxxx; run by ezmlm
- References: <20060209233201.GA5875@fargo> <200602111321.48602.arvidjaar@xxxxxxxxxx> <20060211181440.GA30984@xxxxxxxxxxxxx>
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On Saturday 11 February 2006 21:14, Wayne Davison wrote:
> On Sat, Feb 11, 2006 at 01:21:43PM +0300, Andrey Borzenkov wrote:
> > See this thread: <http://www.zsh.org/mla/workers/2002/msg00542.html>;
> > there was an attempt to fix it in 16949 but apparently it was incomplete
> > and never went in.
>
> I just took a look at that code using Peter's old patch as a start, and
> the assertion that the quotes have been stripped out is not quite true:
> there are still Dnull and Snull characters remaining which indicate that
> there used to be a double- or single-quotes present. This allows us to
> check the string. An overly simple version is this:
>
> --- subst.c 6 Feb 2006 11:57:06 -0000 1.44
> +++ subst.c 11 Feb 2006 18:07:23 -0000
> @@ -2012,6 +2012,8 @@ paramsubst(LinkList l, LinkNode n, char
> */
> multsub(&val, (aspar ? NULL : &aval), &isarr, NULL);
> copied = 1;
> + if (spbreak && (*s == Dnull || *s == Snull))
> + spbreak = 0;
> }
> break;
> case ':':
>
> This will turn off word-splitting if the string started with a single or
> a double quote. This is incomplete because the arg may be something
> more complicated (such as: 'one' 'two' 'three four'), but it seems
> better than what we have now.
>
I am not at all sure that the above is valid in POSIX shell. The word in
${var+word} is a token, and token is delimited by the first blank; so while
you can do ${var+$(any command with blank)} (because command substitution
forms token by itself) you apparently cannot do ${var+foo bar baz}.
That's said, bash accepts the above just fine and correctly preserves quoting:
bash-3.1$ args()
> {
> while [[ $# -gt 0 ]]; do
> echo "$1"
> shift
> done
> }
bash-3.1$ args ${var+"foo bar" baz}
foo bar
baz
So assuming my interpretation is correct, we have two options:
- - turn the above on only is sh (POSIX?) emulation mode on assumption that
multiple words on the right side are invalid anyway
- - attempt to fix it to be compatible with bash i.e. correctly preserve
individual quoted words.
Is it possible to recursively call expansion on rhs word? According to SUS:
"word shall be subjected to tilde expansion, parameter expansion, command
substitution, and arithmetic expansion." so recursively calling expansion
looks the right way to go.
> One question I have is what to do about ${=1:"$@"}? In the patch above,
> I chose to let the double quotes override the '='. If that is not
> desired, change the new "if" to only trigger disallow an spbreak of 2:
>
> + if (spbreak == 1 && (*s == Dnull || *s == Snull))
>
As long as it is documented ...
- -andrey
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