Re: z parameter expansion flag is broken?

[Peter Stephenson <p.w.stephenson@xxxxxxxxxxxx>]

On Sat, 09 Sep 2017 04:13:03 +0900 (JST)
Yuya Amemiya <ghostrevery@xxxxxxxxx> wrote:
> Why does z parameter expansion flag remove leading '-' from result?
> 
> in zsh 5.4.1
> 
> ```
> $ echo ${(z):--a}
> a

That's a bug, but the only new feature is that it now additionally affects
"-" because that's tokenized.  The basic effect is old:

% zsh-5.3.1 -f
% setopt nonomatch
% echo ${(z):-foo*bar}
foobar

Because "-" doesn't usually need quoting, it's more noticeable than with
other metacharacters.

Untokenizing before passing to bufferwords() is the easy fix, and the
result can only be better because anything altered would previously
simply have been dumped by the effect noted by Bart.  However, I'm not
at all convinced bufferwords() needs to dump token characters in this
case --- bufferwords() is a hack that originated as a helper for
completion but is now more widely used.  A more elegant solution (not on
the cards) wouldn't use bufferwords() at all.

pws

diff --git a/Src/subst.c b/Src/subst.c
index 5b1bf89..5df2a8b 100644
--- a/Src/subst.c
+++ b/Src/subst.c
@@ -3747,11 +3747,15 @@ paramsubst(LinkList l, LinkNode n, char **str, int qt, int pf_flags,
 
 	if (isarr) {
 	    char **ap;
-	    for (ap = aval; *ap; ap++)
+	    for (ap = aval; *ap; ap++) {
+		untokenize(*ap);
 		list = bufferwords(list, *ap, NULL, shsplit);
+	    }
 	    isarr = 0;
-	} else
+	} else {
+	    untokenize(val);
 	    list = bufferwords(NULL, val, NULL, shsplit);
+	}
 
 	if (!list || !firstnode(list))
 	    val = dupstring("");
diff --git a/Test/D04parameter.ztst b/Test/D04parameter.ztst
index 3c93990..8dbc1e8 100644
--- a/Test/D04parameter.ztst
+++ b/Test/D04parameter.ztst
@@ -2200,3 +2200,10 @@ F:behavior, see http://austingroupbugs.net/view.php?id=888
 >Option
 >Regular text
 >Option
+
+ (setopt nonomatch
+  print ${(z):-foo-bar*thingy?}
+ )
+0:(z) splitting with remaining tokens
+>foo-bar*thingy?
+