bug#55070: 28.1; desktop-load doesn't work in -nw (non-gui) emacs

[Eric Swenson]

Thanks. It seems really strange that this should be problematic in -nw 
sessions. I could understand not being able to restore windows between a GUI 
and -nw sessions, but I don’t see why, since windows work perfectly well in a 
single frame in a -nw session that restoring them should be problematic.

Can you explain why this is difficult? In -nw sessions the same commands split 
windows perfectly well. So clearly -nw sessions support window splitting — why 
not restoring? (I think a restriction that requires the saving and restoring 
sessions to be the same kind (either both -nw or both GUI) is a perfectly 
sensible restriction.

-- Eric (KN6SIJ)


> On Apr 23, 2022, at 07:25, Eli Zaretskii <eliz@gnu.org> wrote:
> 
> 
>> 
>> From: Eric Swenson <eric@swenson.org>
>> Date: Sat, 23 Apr 2022 06:52:13 -0700
>> Cc: 55070@debbugs.gnu.org, eric=swenson.org@groups.io
>> 
>> I start emacs with a single frame. I create three windows by doing, for 
>> example, C-x 2, and C-x 3. In each window, I read in a file. Then I invoke 
>> M-x desktop-save, and select a directory. I always use ~/.emacs.d.  Then I 
>> exit emacs with C-x C-c.
>> 
>> Then I renter emacs and invoke C-x desktop-load.
>> 
>> If for both sessions, I invoke emacs with “-Q” only, on either macOS or 
>> Linux with Gnome desktop, everything works fine. However, if I invoke emacs 
>> with “-nw -Q”, when I run M-x desktop-load, I only get a single window with 
>> one of the files loaded. The other two files are loaded into buffers, but 
>> their windows were not restored.
>> 
>> I haven’t tried a case where I ran a GUI session first and saved the desktop 
>> and then ran the non-GUI (-nw) session for the restore, but I’m pretty sure 
>> it would also fail. 
>> 
>> I think the “issue” is that desktop-load doesn’t work in the -nw session.
>> 
>> And yes, you can set up the windows using C-x 4 f <filename> as well as the 
>> explicitly creating a second window and splitting and then loading files 
>> into each. It doesn’t really matter. 
> 
> OK, thanks for the details.  They tell me that what you see is the
> intended behavior: desktop.el doesn't restore frames and windows on
> text-mode terminals.  This is because restoring frames and windows in
> a -nw session is problematic, especially if the desktop was saved from
> a GUI session.
> 
> If this causes a lot of inconvenience, maybe we could have a user
> option to allow restoring the frameset in -nw session, for those who
> only ever use -nw sessions.  But we cannot allow that in general, and
> not by default, IMO.