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

[Alan Mackenzie]

Hello, Lars.

On Wed, May 04, 2022 at 08:33:52 +0200, Lars Ingebrigtsen wrote:
> Alan Mackenzie <acm@muc.de> writes:

> > Have I missed some vigorous discussion on emacs-devel which concluded
> > that the key binding should be removed?  When I do C-h w
> > completion-at-point, I get told it's not bound to any key.

> emacs -Q, `C-w completion-at-point':

> completion-at-point is on C-M-i, <menu-bar> <lisp-interaction> <Complete Lisp 
> Symbol>

> And C-M-i is a different way to spell M-<tab>.  So perhaps you have some
> local customisations?

OK, so at least there haven't been breaking changes in Emacs in the last
few weeks.

I think my problem lies in terminfo.

I've still got an old system on my machine (about 4 years old), and I
started Emacs 26.1 on it with emacs -Q.  I type

    M-: (lookup-key input-decode-map "\C-\M-i") RET

I get nil.

When I start Emacs 26.1, the same binary, on my up to date system and
type that incantation, I get [backtab].

I think this has happened very recently, within the last couple of weeks
or so.  I don't think the problem is in the kernel, rather it's in some
user-space supporting software close to the kernel.  The comments in
term.c suggest something for "backtab" is loaded from terminfo.

The trouble is, there is no package called "terminfo" on my GNU/Linux.
I don't know where to find it.  Have you any ideas?

My problem might even merit an entry in the PROBLEMS file.

> -- 
> (domestic pets only, the antidote for overdose, milk.)
>    bloggy blog: http://lars.ingebrigtsen.no

-- 
Alan Mackenzie (Nuremberg, Germany).