bug#25208: 24.5; man output uses wrong width

[Olaf Dietsche <olaf--mail.bug-gnu-emacs@olafdietsche.de>]

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).