bug#25208: 24.5; man output uses wrong width

bug#25208: 24.5; man output uses wrong width

[Olaf Dietsche]

I use a wide display and Emacs full-screen.

- emacs -Q
- Make the Emacs frame full-screen, so it is wider than high and shows
  only one window.
- M-x man RET ps RET -- any command works

Now the frame will be split into two windows side by side, one showing
the man page of `ps`. The man page will contain long lines, which are
truncated instead of wrapped around. You can see the whole lines, when
you scroll horizontally, of course.

This will not happen, if the frame is already split horizontally in two
equal wide windows. When you move the vertical divider to the left or
right and invoke another man command, you can see, that man always uses
the width of the starting window instead of the target (displaying)
window.




In GNU Emacs 24.5.1 (x86_64-pc-linux-gnu, GTK+ Version 3.18.9)
 of 2016-04-17 on lgw01-04, modified by Debian
Windowing system distributor `The X.Org Foundation', version 11.0.11803000
System Description:	Ubuntu 16.04 LTS

Configured using:
 `configure --build x86_64-linux-gnu --prefix=/usr
 --sharedstatedir=/var/lib --libexecdir=/usr/lib
 --localstatedir=/var/lib --infodir=/usr/share/info
 --mandir=/usr/share/man --with-pop=yes
 --enable-locallisppath=/etc/emacs24:/etc/emacs:/usr/local/share/emacs/24.5/site-lisp:/usr/local/share/emacs/site-lisp:/usr/share/emacs/24.5/site-lisp:/usr/share/emacs/site-lisp
 --build x86_64-linux-gnu --prefix=/usr --sharedstatedir=/var/lib
 --libexecdir=/usr/lib --localstatedir=/var/lib
 --infodir=/usr/share/info --mandir=/usr/share/man --with-pop=yes
 --enable-locallisppath=/etc/emacs24:/etc/emacs:/usr/local/share/emacs/24.5/site-lisp:/usr/local/share/emacs/site-lisp:/usr/share/emacs/24.5/site-lisp:/usr/share/emacs/site-lisp
 --with-x=yes --with-x-toolkit=gtk3 --with-toolkit-scroll-bars
 'CFLAGS=-g -O2 -fstack-protector-strong -Wformat
 -Werror=format-security -Wall' 'CPPFLAGS=-Wdate-time
 -D_FORTIFY_SOURCE=2' 'LDFLAGS=-Wl,-Bsymbolic-functions -Wl,-z,relro''

Important settings:
  value of $LC_MESSAGES: C
  value of $LANG: de_DE.UTF-8
  value of $XMODIFIERS: @im=none
  locale-coding-system: utf-8-unix

Major mode: Lisp Interaction

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Recent messages:
For information about GNU Emacs and the GNU system, type C-h C-a.
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bug#25208: 24.5; man output uses wrong width

[Mark Oteiza]

Olaf Dietsche <olaf--mail.bug-gnu-emacs@olafdietsche.de> writes:

> I use a wide display and Emacs full-screen.
>
> - emacs -Q
> - Make the Emacs frame full-screen, so it is wider than high and shows
>   only one window.
> - M-x man RET ps RET -- any command works
>
> Now the frame will be split into two windows side by side, one showing
> the man page of `ps`. The man page will contain long lines, which are
> truncated instead of wrapped around. You can see the whole lines, when
> you scroll horizontally, of course.
>
> This will not happen, if the frame is already split horizontally in two
> equal wide windows. When you move the vertical divider to the left or
> right and invoke another man command, you can see, that man always uses
> the width of the starting window instead of the target (displaying)
> window.

This was fixed before the latest release in a4b0fffe25. See the bugs
mentioned in this commit (Bug#2588, bug#5054, bug#9084, bug#17831).

bug#25208: 24.5; man output uses wrong width

[Eli Zaretskii]

> From: Olaf Dietsche <olaf--mail.bug-gnu-emacs@olafdietsche.de>
> Date: Thu, 15 Dec 2016 14:08:13 +0100
> 
> I use a wide display and Emacs full-screen.
> 
> - emacs -Q
> - Make the Emacs frame full-screen, so it is wider than high and shows
>   only one window.
> - M-x man RET ps RET -- any command works
> 
> Now the frame will be split into two windows side by side, one showing
> the man page of `ps`. The man page will contain long lines, which are
> truncated instead of wrapped around. You can see the whole lines, when
> you scroll horizontally, of course.
> 
> This will not happen, if the frame is already split horizontally in two
> equal wide windows. When you move the vertical divider to the left or
> right and invoke another man command, you can see, that man always uses
> the width of the starting window instead of the target (displaying)
> window.

This is the intended behavior.  What would you like to see instead?

Thanks.

bug#25208: 24.5; man output uses wrong width

[Olaf Dietsche]

Eli Zaretskii <eliz@gnu.org> writes:

>> From: Olaf Dietsche <olaf--mail.bug-gnu-emacs@olafdietsche.de>
>> Date: Thu, 15 Dec 2016 14:08:13 +0100
>> 
>> I use a wide display and Emacs full-screen.
>> 
>> - emacs -Q
>> - Make the Emacs frame full-screen, so it is wider than high and shows
>>   only one window.
>> - M-x man RET ps RET -- any command works
>> 
>> Now the frame will be split into two windows side by side, one showing
>> the man page of `ps`. The man page will contain long lines, which are
>> truncated instead of wrapped around. You can see the whole lines, when
>> you scroll horizontally, of course.
>> 
>> This will not happen, if the frame is already split horizontally in two
>> equal wide windows. When you move the vertical divider to the left or
>> right and invoke another man command, you can see, that man always uses
>> the width of the starting window instead of the target (displaying)
>> window.
>
> This is the intended behavior.  What would you like to see instead?

Sorry for the incomplete bug report. I would expect to see the man
page's lines properly wrapped in the target window, so I can read it
without the need for scrolling horizontally.

bug#25208: 24.5; man output uses wrong width

[Eli Zaretskii]

> From: Olaf Dietsche <olaf--mail.bug-gnu-emacs@olafdietsche.de>
> Cc: 25208@debbugs.gnu.org
> Date: Thu, 15 Dec 2016 18:20:39 +0100
> 
> > This is the intended behavior.  What would you like to see instead?
> 
> Sorry for the incomplete bug report. I would expect to see the man
> page's lines properly wrapped in the target window, so I can read it
> without the need for scrolling horizontally.

I think if you set truncate-partial-width-windows to nil, you will
have what you want.

But Mark says this was fixed, so maybe I don't understand the issue
well enough.

bug#25208: 24.5; man output uses wrong width

[Olaf Dietsche]

Eli Zaretskii <eliz@gnu.org> writes:

>> From: Olaf Dietsche <olaf--mail.bug-gnu-emacs@olafdietsche.de>
>> Cc: 25208@debbugs.gnu.org
>> Date: Thu, 15 Dec 2016 18:20:39 +0100
>> 
>> > This is the intended behavior.  What would you like to see instead?
>> 
>> Sorry for the incomplete bug report. I would expect to see the man
>> page's lines properly wrapped in the target window, so I can read it
>> without the need for scrolling horizontally.
>
> I think if you set truncate-partial-width-windows to nil, you will
> have what you want.

Setting truncate-partial-width-windows to nil (and truncate-lines to t)
doesn't change the observed behaviour.

This is not a general problem with line truncation. In this case it
isn't Emacs doing the formatting, but the external program `man`. Emacs
does so by setting the COLUMNS environment variable before calling man.

Man will then format according to the given width, which is the width of
the current window before being split in half.

> But Mark says this was fixed, so maybe I don't understand the issue
> well enough.

Whatever might have been fixed more than two years ago (#17831), it
doesn't show up in my Emacs (24.5.1, Ubuntu 16.04).

bug#25208: 24.5; man output uses wrong width

[Eli Zaretskii]

> From: Olaf Dietsche <olaf--mail.bug-gnu-emacs@olafdietsche.de>
> Cc:25208@debbugs.gnu.org
> Date: Thu, 15 Dec 2016 22:31:30 +0100
> 
> This is not a general problem with line truncation. In this case it
> isn't Emacs doing the formatting, but the external program `man`. Emacs
> does so by setting the COLUMNS environment variable before calling man.
> 
> Man will then format according to the given width, which is the width of
> the current window before being split in half.

Right, so I did misunderstand.  Sorry about that.

> > But Mark says this was fixed, so maybe I don't understand the issue
> > well enough.
> 
> Whatever might have been fixed more than two years ago (#17831), it
> doesn't show up in my Emacs (24.5.1, Ubuntu 16.04).

That fix is in Emacs 25.1, not in 24.5, AFAICS.

bug#25208: 24.5; man output uses wrong width

[Olaf Dietsche]

Eli Zaretskii <eliz@gnu.org> writes:

>> From: Olaf Dietsche <olaf--mail.bug-gnu-emacs@olafdietsche.de>
>> Cc:25208@debbugs.gnu.org
>> Date: Thu, 15 Dec 2016 22:31:30 +0100
>> 
>> > But Mark says this was fixed, so maybe I don't understand the issue
>> > well enough.
>> 
>> Whatever might have been fixed more than two years ago (#17831), it
>> doesn't show up in my Emacs (24.5.1, Ubuntu 16.04).
>
> That fix is in Emacs 25.1, not in 24.5, AFAICS.

Ok, thank you for clarifying. I'll have a look.