3.0.5: eval `resize` messes up

3.0.5: eval `resize` messes up

[Clint Olsen]

Hello:

Is there a known problem with using eval `resize`?  I used to be able to do
this with 3.0.2 (and any other shell).  Is there some setting I might be
missing?  I'm on HP-UX 10.20.

Thanks,

-Clint

Re: 3.0.5: eval `resize` messes up

[Tatsuo Furukawa]

Hi,

Clint> Is there a known problem with using eval `resize`?  I used to
Clint> be able to do this with 3.0.2 (and any other shell).  Is there
Clint> some setting I might be missing?  I'm on HP-UX 10.20.

Is this problem "If you evaluated `resize`, zsh is not measure
terminal size"?

If so, this is normal zsh action. (Your setting is sufficient.)  Zsh
3.0.5 trust LINES and COLUMNS.  If you don't set LINES and COLUMNS,
zsh measures terminal size.  But If you set LINES and COLUMNS, zsh
trusts its value.  Therefore, if you execute "eval 'resize`", you must
always execute "eval `resize`" when terminal size is changed.

I don't know whether this is zsh's feature or bug.  I just read source
code.

-- 
---------------------------------------------------------------
[(hp)]  Hewlett-Packard Japan, Ltd     Tatsuo Furukawa 
                                       tatsuo@kobe.hp.com

Re: 3.0.5: eval `resize` messes up

[Clint Olsen]

On May 18, Tatsuo Furukawa wrote:
> 
> Is this problem "If you evaluated `resize`, zsh is not measure
> terminal size"?
 
Yes.  Resize alone seems to corectly meausre the new window size.

> If so, this is normal zsh action. (Your setting is sufficient.)  Zsh
> 3.0.5 trust LINES and COLUMNS.  If you don't set LINES and COLUMNS, zsh
> measures terminal size.  But If you set LINES and COLUMNS, zsh trusts its
> value.  Therefore, if you execute "eval 'resize`", you must always
> execute "eval `resize`" when terminal size is changed.

Setting LINES and COLUMNS is precisely why I use "eval `resize`".  It seems
to work on every other shell except Zsh.  In fact it worked on Zsh 3.0.2.

-Clint

Re: 3.0.5: eval `resize` messes up

[Bart Schaefer]

On May 18,  4:45pm, Tatsuo Furukawa wrote:
} Subject: Re: 3.0.5: eval `resize` messes up
}
} 3.0.5 trust LINES and COLUMNS.  If you don't set LINES and COLUMNS,
} zsh measures terminal size.  But If you set LINES and COLUMNS, zsh
} trusts its value.
} 
} I don't know whether this is zsh's feature or bug.

It's a feature that has a bug, as far as I'm concerned.  Zsh went from
not believing LINES and COLUMNS when it should have, to believing them
even when it should not.  However, it's very difficult to come up with
an accurate expression for when they ought to be recognized.

On May 18,  1:10am, Clint Olsen wrote:
} Subject: Re: 3.0.5: eval `resize` messes up
}
} Setting LINES and COLUMNS is precisely why I use "eval `resize`".  It
} seems to work on every other shell except Zsh.  In fact it worked on
} Zsh 3.0.2.

Run "resize" without the "eval" wrapper and see what it spits out.  It
may be emitting some syntax that zsh doesn't like.  (And if you still
have 3.0.2 around, run it there too and see it it differs at all.)

-- 
Bart Schaefer                                 Brass Lantern Enterprises
http://www.well.com/user/barts              http://www.brasslantern.com

Re: 3.0.5: eval `resize` messes up

[Clint Olsen]

On May 18, Bart Schaefer wrote:
> } Setting LINES and COLUMNS is precisely why I use "eval `resize`".  It
> } seems to work on every other shell except Zsh.  In fact it worked on
> } Zsh 3.0.2.
> 
> Run "resize" without the "eval" wrapper and see what it spits out.  It
> may be emitting some syntax that zsh doesn't like.  (And if you still
> have 3.0.2 around, run it there too and see it it differs at all.)

Resize spits out the usual:

COLUMNS=77;
LINES=30;
export COLUMNS LINES;

This doesn't change with shell versions.

There are no syntax errors on 3.0.5.  It just plain doesn't respond to the
command.  3.0.2 seems to work fine.

-Clint

Re: 3.0.5: eval `resize` messes up

[Bart Schaefer]

On May 19,  9:40am, Clint Olsen wrote:
} Subject: Re: 3.0.5: eval `resize` messes up
}
} On May 19, Bart Schaefer wrote:
} > 
} > OK, next question ... what exactly does it not do, that 3.0.2 does?
} 
} Eval `resize` no longer sets the window to the new size so that programs
} like less etc. etc. use the correct terminal window size.

Ah!  Now we're getting somewhere.  If you look in Src/utils.c at around
lines 875-885 you'll see that setting the window size now happens only
when COLUMNS and LINES actually change (rather than on every settyinfo()
as it did before) and that it's now conditional upon `interact' being
true.  If you're interested in running the debugger, you could check the
value of the `from' parameter in adjustwinsize() and see whether that
`if (interact && ...)' case is executing.

The first thing I'd check, though, is that configure did its job correctly
so that TIOCGWINSZ is actually defined at that point when compiling utils.c.
The code in adjustwinsize() is definitely working for me on Linux; I tried
this experiment:

zagzig[38] foo=$(resize)
( stretch the xterm to be much bigger than it was )
zagzig[39] vi
( verify that vim is using the new terminal size )
zagzig[40] eval $foo
zagzig[41] unset LINES COLUMNS
zagzig[42] vi
( vim is now using the old, smaller terminal size )

With LINES and COLUMNS unset, the only place vim could have read the smaller
terminal size is from the tty driver, so zsh must have reset it at the time
of the `eval $foo'.

-- 
Bart Schaefer                                 Brass Lantern Enterprises
http://www.well.com/user/barts              http://www.brasslantern.com