Re: What's happened to M-<tab> `completion-at-point'?

[Alan Mackenzie]

Hello, Eli.

On Wed, May 04, 2022 at 19:40:01 +0300, Eli Zaretskii wrote:
> > Date: Wed, 4 May 2022 16:34:38 +0000
> > Cc: emacs-devel@gnu.org
> > From: Alan Mackenzie <acm@muc.de>

> > > > Suddenly, my M-<tab> `completion-at-point' isn't working.  Would
> > > > somebody please explain?

> > > If you press "ESC TAB" instead, what does Emacs do then?

> > I get the message

> >     [backtab] is undefined

> And what does "C-h l" show after that?

If I first press ESC TAB and C-h l, followed by C-M-i and C-h l, I get
this:

 ESC TAB ;; nil
 C-h l   ;; view-lossage
 ESC TAB ;; nil
 C-h l   ;; view-lossage

..

I think I've found the problem.  A new version of ncurses was
installed on my machine on 2022-05-01.  It contains a version of
terminfo, specifically /etc/terminfo/l/linux.

The new version is ncurses-6.3_p20211106.  The old version was
ncurses-6.2_p20210619.

So, possibly we need to amend Emacs (? src/term.c) to work properly on
this version of the Linux console.  I don't think this affects any other
type of terminal.  In particular, Emacs works OK for me under XFCE4 on X.

I think I'll be raising a bug report for this.

-- 
Alan Mackenzie (Nuremberg, Germany).