* "var=value exec > file" ignores the assignment?
@ 2015-04-07 15:51 Jun T.
2015-04-08 17:13 ` Bart Schaefer
0 siblings, 1 reply; 5+ messages in thread
From: Jun T. @ 2015-04-07 15:51 UTC (permalink / raw)
To: zsh-workers
If 'exec' has no command arg but has both parameter assignment
and redirection, the assignment seems to be ignored.
The following script outputs "x = 0" into test.log:
#!/usr/local/bin/zsh
setopt POSIX_BUILTINS
x=0
x=1 exec > test.log
echo "x = $x"
'ksh' and 'bash -posix' (or /bin/sh) output "x = 1", which I
guess what POSIX requires.
Moreover, assuming there is no command named 'junk',
x=$(junk) exec > test.log
does NOT issue "command not found: junk" error.
The following patch *seems* to fix these, but I believe this
is at most a partial fix (or regression at the worst).
Either with or without the patch, and either POSIX_BUILTINS is
set or unset, the following outputs "x = 1" (/bin/sh outputs
"x = 0"). But I don't know whether this need be fixed (or how
to fix it if it need be).
x=0
true | x=1 exec | true
echo "x = $x"
diff --git a/Src/exec.c b/Src/exec.c
index 1a6149a..fdb2470 100644
--- a/Src/exec.c
+++ b/Src/exec.c
@@ -3305,6 +3305,13 @@ execcmd(Estate state, int input, int output, int how, int last1)
closemn(mfds, i, REDIR_CLOSE);
if (nullexec) {
+ /*
+ * If nullexec is 2, we have variables to add with the redirections
+ * in place.
+ */
+ if (varspc)
+ addvars(state, varspc, 0);
+ lastval = errflag ? errflag : cmdoutval;
if (nullexec == 1) {
/*
* If nullexec is 1 we specifically *don't* restore the original
@@ -3315,13 +3322,6 @@ execcmd(Estate state, int input, int output, int how, int last1)
zclose(save[i]);
goto done;
}
- /*
- * If nullexec is 2, we have variables to add with the redirections
- * in place.
- */
- if (varspc)
- addvars(state, varspc, 0);
- lastval = errflag ? errflag : cmdoutval;
if (isset(XTRACE)) {
fputc('\n', xtrerr);
fflush(xtrerr);
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: "var=value exec > file" ignores the assignment?
2015-04-07 15:51 "var=value exec > file" ignores the assignment? Jun T.
@ 2015-04-08 17:13 ` Bart Schaefer
2015-04-09 16:13 ` Jun T.
0 siblings, 1 reply; 5+ messages in thread
From: Bart Schaefer @ 2015-04-08 17:13 UTC (permalink / raw)
To: zsh-workers
On Apr 8, 12:51am, Jun T. wrote:
}
} If 'exec' has no command arg but has both parameter assignment
} and redirection, the assignment seems to be ignored.
Hm. This probably comes down to the behavior of "special" built-ins
which are supposed to retain the results of environment assignments.
It's possible (likely?) your patch should add a POSIX_BUILTINS test.
I'm not sure why we skip the XTRACE when nullexec == 1. If your patch
is otherwise correct, there doesn't seem to be any other reason to
distinguish the 1 and 2 cases.
} Either with or without the patch, and either POSIX_BUILTINS is
} set or unset, the following outputs "x = 1" (/bin/sh outputs
} "x = 0"). But I don't know whether this need be fixed (or how
} to fix it if it need be).
}
} x=0
} true | x=1 exec | true
} echo "x = $x"
This is a curious one. Normally zsh would fork off "x=1 exec" so the
assignment would only affect a subshell, but that is apparently short-
circuited because the subshell has nothing else to do. This:
x=0
true | x=1 | true
also assigns so $x == 1 whereas this:
true | { x=1 } | true
which should otherwise be equivalent, leaves $x == 0. Anyway the point
is I don't think the presence of "exec" has anything to do with this
particular behavior.
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: "var=value exec > file" ignores the assignment?
2015-04-08 17:13 ` Bart Schaefer
@ 2015-04-09 16:13 ` Jun T.
2015-04-15 19:52 ` Peter Stephenson
0 siblings, 1 reply; 5+ messages in thread
From: Jun T. @ 2015-04-09 16:13 UTC (permalink / raw)
To: zsh-workers
2015/04/09 02:13, Bart Schaefer <schaefer@brasslantern.com> wrote:
> It's possible (likely?) your patch should add a POSIX_BUILTINS test.
In the following case:
x=$(command) exec > file
we want to execute the 'command' unconditionally, but maybe do not want to
set the value of x if POSIX_BUILTINS is unset.
I wonder what is the easiest way (if any) to achieve this.
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: "var=value exec > file" ignores the assignment?
2015-04-09 16:13 ` Jun T.
@ 2015-04-15 19:52 ` Peter Stephenson
2015-04-15 20:27 ` Peter Stephenson
0 siblings, 1 reply; 5+ messages in thread
From: Peter Stephenson @ 2015-04-15 19:52 UTC (permalink / raw)
To: zsh-workers
On Fri, 10 Apr 2015 01:13:50 +0900
"Jun T." <takimoto-j@kba.biglobe.ne.jp> wrote:
> 2015/04/09 02:13, Bart Schaefer <schaefer@brasslantern.com> wrote:
>
> > It's possible (likely?) your patch should add a POSIX_BUILTINS test.
>
> In the following case:
>
> x=$(command) exec > file
>
> we want to execute the 'command' unconditionally, but maybe do not want to
> set the value of x if POSIX_BUILTINS is unset.
> I wonder what is the easiest way (if any) to achieve this.
This (based on the previous patch) might be good enough. It could
probably do with a couple of tests.
diff --git a/Src/exec.c b/Src/exec.c
index 2ee37d0..2a8185c 100644
--- a/Src/exec.c
+++ b/Src/exec.c
@@ -3305,6 +3305,20 @@ execcmd(Estate state, int input, int output, int how, int last1)
closemn(mfds, i, REDIR_CLOSE);
if (nullexec) {
+ /*
+ * If nullexec is 2, we have variables to add with the redirections
+ * in place. If nullexec is 1, we may have variables but they
+ * need the standard restore logic.
+ */
+ if (varspc) {
+ LinkList restorelist = 0, removelist = 0;
+ if (!isset(POSIXBUILTINS) && nullexec != 2)
+ save_params(state, varspc, &restorelist, &removelist);
+ addvars(state, varspc, 0);
+ if (restorelist)
+ restore_params(restorelist, removelist);
+ }
+ lastval = errflag ? errflag : cmdoutval;
if (nullexec == 1) {
/*
* If nullexec is 1 we specifically *don't* restore the original
@@ -3315,13 +3329,6 @@ execcmd(Estate state, int input, int output, int how, int last1)
zclose(save[i]);
goto done;
}
- /*
- * If nullexec is 2, we have variables to add with the redirections
- * in place.
- */
- if (varspc)
- addvars(state, varspc, 0);
- lastval = errflag ? errflag : cmdoutval;
if (isset(XTRACE)) {
fputc('\n', xtrerr);
fflush(xtrerr);
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: "var=value exec > file" ignores the assignment?
2015-04-15 19:52 ` Peter Stephenson
@ 2015-04-15 20:27 ` Peter Stephenson
0 siblings, 0 replies; 5+ messages in thread
From: Peter Stephenson @ 2015-04-15 20:27 UTC (permalink / raw)
To: zsh-workers
On Wed, 15 Apr 2015 20:52:18 +0100
Peter Stephenson <p.w.stephenson@ntlworld.com> wrote:
> This (based on the previous patch) might be good enough. It could
> probably do with a couple of tests.
Let me know if you've heard this one... That's not what I meant. You
know what I meant.
pws
diff --git a/Test/A04redirect.ztst b/Test/A04redirect.ztst
index 13f1f7c..602341d 100644
--- a/Test/A04redirect.ztst
+++ b/Test/A04redirect.ztst
@@ -538,3 +538,20 @@
print $functions[noredirfn]
0:Output from $functions[] for definition with no redirection
> print This rather boring function has no redirection.
+
+ (x=43
+ x=$(print This should appear, really >&2; print Not used) exec >test.log
+ print x=$x)
+ cat test.log
+0:Assignment with exec used for redirection: no POSIX_BUILTINS
+>x=43
+?This should appear, really
+
+ (setopt POSIX_BUILTINS
+ x=45
+ x=$(print This should appear, too >&2; print And this) exec >test.log
+ print x=$x)
+ cat test.log
+0:Assignment with exec used for redirection: POSIX_BUILTINS
+>x=And this
+?This should appear, too
^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2015-04-15 20:28 UTC | newest]
Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed)
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2015-04-07 15:51 "var=value exec > file" ignores the assignment? Jun T.
2015-04-08 17:13 ` Bart Schaefer
2015-04-09 16:13 ` Jun T.
2015-04-15 19:52 ` Peter Stephenson
2015-04-15 20:27 ` Peter Stephenson
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