Opts -i and -s no longer work together, haven't for while

Opts -i and -s no longer work together, haven't for while

[Bart Schaefer]

Here's zsh-2.4 (wow, ancient):

schaefer[792] src/zsh -si <<<'echo foo'
torch<502> foo
torch<503> % 

(exited -- the % there is the newer zsh printing the end-of-line mark)

But by the time we get to zsh-3.0.5:

schaefer[794] Src/zsh -fsi <<<'echo foo'
torch% 

(the shell is now reading from the terminal and ignores stdin)

I have no idea whether that was intentional.  Bash appears to work like
zsh-2.4 did.  The doc for -i explicitly says

-i
     Force shell to be interactive.  It is still possible to specify a
     script to execute.

but as far as I can tell "zsh -i" always simply sets $@ and never treats
its first argument as a script file.  So this has been broken for about
25 years ...

Re: Opts -i and -s no longer work together, haven't for while

[Bart Schaefer]

On Oct 10, 11:12pm, Bart Schaefer wrote:
}
} But by the time we get to zsh-3.0.5:
} 
} schaefer[794] Src/zsh -fsi <<<'echo foo'
} torch% 
} 
} (the shell is now reading from the terminal and ignores stdin)

So the problem appears to be that ZLE remains enabled whenever the
standard OUTPUT is a terminal, even if the standard INPUT is not,
and having ZLE turned on (as it is by default from sometime after
2.4) overrides everything else, ignores the command line script
file name, and reads from the terminal.

So you have to use "zsh +Z -fi ..." to get the effect I expected.

Do we want to change this, or document it?  We'd have to move the
default setting of opts[USEZLE] from zsh_main() into parseargs(),
I think.

Re: Opts -i and -s no longer work together, haven't for while

[Bart Schaefer]

On Oct 11,  9:52am, Bart Schaefer wrote:
}
} So the problem appears to be that ZLE remains enabled whenever the
} standard OUTPUT is a terminal, even if the standard INPUT is not

It's actually worse than that, it acquires /dev/tty if std(in|out|err)
are redirected, so you really do have to use +Z to make it work.

} Do we want to change this, or document it?  We'd have to move the
} default setting of opts[USEZLE] from zsh_main() into parseargs(),
} I think.

There are a couple of ways to spin this.  We can either disable ZLE
any time the -s option is given, or we can set ZLE from isatty(0)
when -s is given.  The latter is more consistent with the past two
decades of behavior.

Then we have to decide what to do of -Z is explicitly given.  There
is also the effect of SINGLECOMMAND (-t) to consider; it overrides -Z
and turns off prompting as well, unless -i is given along with it.
So I think -s should also take precedence.

So, please give feedback on this patch.  To compare with the previous
behavior, try these test cases:

    zsh -fs <<<setopt		# should work the same before/after
    zsh +Z -fs <<<setopt	# should work the same before/after
    zsh +Z -fis <<<setopt	# should work the same before/after
    zsh -fis <<<setopt		# should differ 
    zsh -Z -fis <<<setopt	# should differ 
    zsh -fist <<<setopt		# differ 
    zsh -fi =(<<<setopt)	# same
    zsh -ft =(<<<setopt)	# same
    zsh -Z -ft =(<<<setopt)	# same
    zsh -fit =(<<<setopt)	# same

diff --git a/Src/init.c b/Src/init.c
index 6d005dc..c4da7a3 100644
--- a/Src/init.c
+++ b/Src/init.c
@@ -243,12 +243,22 @@ parseargs(char **argv, char **runscript)
      */
     opts[MONITOR] = 2;   /* may be unset in init_io() */
     opts[HASHDIRS] = 2;  /* same relationship to INTERACTIVE */
+    opts[USEZLE] = 1;    /* see below, related to SHINSTDIN */
     opts[SHINSTDIN] = 0;
     opts[SINGLECOMMAND] = 0;
 
     if (parseopts(NULL, &argv, opts, &cmd, NULL))
 	exit(1);
 
+    /*
+     * USEZLE remains set if the shell has access to a terminal and
+     * is not reading from some other source as indicated by SHINSTDIN.
+     * SHINSTDIN becomes set below if there is no command argument,
+     * but it is the explicit setting (or not) that matters to USEZLE.
+     */
+    if (opts[SHINSTDIN])
+	opts[USEZLE] = (opts[USEZLE] && isatty(0));
+
     paramlist = znewlinklist();
     if (*argv) {
 	if (unset(SHINSTDIN)) {
@@ -1608,8 +1618,7 @@ zsh_main(UNUSED(int argc), char **argv)
     emulate(zsh_name, 1, &emulation, opts);   /* initialises most options */
     opts[LOGINSHELL] = (**argv == '-');
     opts[PRIVILEGED] = (getuid() != geteuid() || getgid() != getegid());
-    opts[USEZLE] = 1;   /* may be unset in init_io() */
-    /* sets INTERACTIVE, SHINSTDIN and SINGLECOMMAND */
+    /* sets ZLE, INTERACTIVE, SHINSTDIN and SINGLECOMMAND */
     parseargs(argv, &runscript);
 
     SHTTY = -1;

-- 
Barton E. Schaefer

Re: Opts -i and -s no longer work together, haven't for while

[Peter Stephenson]

On Sat, 11 Oct 2014 13:07:08 -0700
Bart Schaefer <schaefer@brasslantern.com> wrote:
> } Do we want to change this, or document it?  We'd have to move the
> } default setting of opts[USEZLE] from zsh_main() into parseargs(),
> } I think.
> 
> There are a couple of ways to spin this.  We can either disable ZLE
> any time the -s option is given, or we can set ZLE from isatty(0)
> when -s is given.  The latter is more consistent with the past two
> decades of behavior.

Probably be good to allow ZLE if there's away of doing it, yes.
 
> Then we have to decide what to do of -Z is explicitly given.  There
> is also the effect of SINGLECOMMAND (-t) to consider; it overrides -Z
> and turns off prompting as well, unless -i is given along with it.
> So I think -s should also take precedence.

From what you're saying, two decades of behaviour haven't done anyone
much use at all when combining -i and -s --- the -s is effectively
ignroed.  So actually I don't think it's all that crucial as long as the
only changes are where both are given, which is what you're suggesting:

>     zsh -fis <<<setopt		# should differ 
>     zsh -Z -fis <<<setopt	# should differ 
>     zsh -fist <<<setopt		# differ 

-s being the part of the business that has been ignored, it's hard to
see how making it take precedence now can break anything that was
working and that logically should have worked.  So it all sounds fine
to me.

pws

Re: Opts -i and -s no longer work together, haven't for while

[Bart Schaefer]

On Oct 12,  6:06pm, Peter Stephenson wrote:
}
} -s being the part of the business that has been ignored, it's hard to
} see how making it take precedence now can break anything that was
} working and that logically should have worked.  So it all sounds fine
} to me.

Here's a revised patch that also fixes a couple of other small items:

I added a bit more detail to the comment in parseargs() because the
comment mentioning init_io() was removed from zsh_main().  

The caller of init_io() expects that shout might become NULL, but the
setvbuf() call in init_io() did not consider that possibility.

The word "interative" in a comment was a typo.

diff --git a/Src/init.c b/Src/init.c
index 6d005dc..68d3612 100644
--- a/Src/init.c
+++ b/Src/init.c
@@ -243,12 +243,24 @@ parseargs(char **argv, char **runscript)
      */
     opts[MONITOR] = 2;   /* may be unset in init_io() */
     opts[HASHDIRS] = 2;  /* same relationship to INTERACTIVE */
+    opts[USEZLE] = 1;    /* see below, related to SHINSTDIN */
     opts[SHINSTDIN] = 0;
     opts[SINGLECOMMAND] = 0;
 
     if (parseopts(NULL, &argv, opts, &cmd, NULL))
 	exit(1);
 
+    /*
+     * USEZLE remains set if the shell has access to a terminal and
+     * is not reading from some other source as indicated by SHINSTDIN.
+     * SHINSTDIN becomes set below if there is no command argument,
+     * but it is the explicit setting (or not) that matters to USEZLE.
+     * USEZLE may also become unset in init_io() if the shell is not
+     * interactive or the terminal cannot be re-opened read/write.
+     */
+    if (opts[SHINSTDIN])
+	opts[USEZLE] = (opts[USEZLE] && isatty(0));
+
     paramlist = znewlinklist();
     if (*argv) {
 	if (unset(SHINSTDIN)) {
@@ -603,7 +615,7 @@ init_shout(void)
 
     if (SHTTY == -1)
     {
-	/* Since we're interative, it's nice to have somewhere to write. */
+	/* Since we're interactive, it's nice to have somewhere to write. */
 	shout = stderr;
 	return;
     }
@@ -616,7 +628,8 @@ init_shout(void)
     /* Associate terminal file descriptor with a FILE pointer */
     shout = fdopen(SHTTY, "w");
 #ifdef _IOFBF
-    setvbuf(shout, shoutbuf, _IOFBF, BUFSIZ);
+    if (shout)
+	setvbuf(shout, shoutbuf, _IOFBF, BUFSIZ);
 #endif
   
     gettyinfo(&shttyinfo);	/* get tty state */
@@ -1608,8 +1621,7 @@ zsh_main(UNUSED(int argc), char **argv)
     emulate(zsh_name, 1, &emulation, opts);   /* initialises most options */
     opts[LOGINSHELL] = (**argv == '-');
     opts[PRIVILEGED] = (getuid() != geteuid() || getgid() != getegid());
-    opts[USEZLE] = 1;   /* may be unset in init_io() */
-    /* sets INTERACTIVE, SHINSTDIN and SINGLECOMMAND */
+    /* sets ZLE, INTERACTIVE, SHINSTDIN and SINGLECOMMAND */
     parseargs(argv, &runscript);
 
     SHTTY = -1;

-- 
Barton E. Schaefer